Dried hop cones, the part used, with a cup of hop tea.

Herbs & Botanicals · Herbs · The beer herb, also sold as a sleep and menopause supplement, with only low-certainty evidence for any use

Hops

Q: Do hops help you sleep?

A little, in some trials, but the evidence is weak. Most sleep trials used valerian and hops together. The largest (184 adults) found modest self-reported improvement and few results that beat placebo, and sleep-lab recordings did not differ. A smaller trial found valerian-hops shortened sleep latency while valerian alone did not. No trial tested hops alone for insomnia. The EU lists hops as a traditional medicine to aid sleep, based on long use.

Q: Is valerian-and-hops better than hops alone?

We do not know. No trial compared them. In one trial the valerian-hops combination beat placebo while valerian alone did not, which hints that hops add something, but hops alone were not tested for insomnia.

Q: Do hops reduce anxiety or stress?

One 36-person pilot found lower anxiety, depression and stress scores after 4 weeks of hop extract than placebo in young adults with mild symptoms. Morning cortisol did not change. It has not been repeated, so the certainty is low. A review lists hops among plants that act on the brain's calming system, but gives no hops-specific figures in its abstract.

Q: Do hops help menopause hot flashes?

Results are mixed. Some small trials of hop extract beat placebo and some did not; a soy-hop combination beat placebo; and a review calls the data few and inconclusive. Hops contain a strong plant estrogen, so see the safety section first.

Q: Can I use hops if I have breast cancer or another hormone-sensitive condition?

Ask your doctor first. Hops contain 8-prenylnaringenin, described as one of the most potent plant estrogens. Cell and animal findings are mixed and no study has followed breast or womb tissue in women for years. Short trials saw no change in womb lining thickness or hormones. Also ask before using hops with tamoxifen or aromatase inhibitors.

Q: Can I take hops with sleeping pills, alcohol or other medicines?

Ask your pharmacist. The EU says no interactions have been reported, but no study tested this. In lab tests hop compounds strengthen the brain's calming system and alcohol added to that effect, so extra sleepiness is possible in theory. In test tubes a hop extract also blocked liver enzymes (CYP2C8, 2C9, 2C19) that clear some medicines; no human study confirms this.

Q: Are hops safe in pregnancy, breastfeeding or for children?

Not recommended. The EU says safety in pregnancy and breastfeeding is not established, no fertility data exist, and use under age 12 is not recommended. A placental cell test found no harm at the concentrations tested, but studies in pregnant women are needed.

Q: Are hops dangerous to dogs?

Yes. Veterinary reports describe dogs, especially after eating spent brewing hops, with fever, fast breathing, vomiting and seizures. In a case series four of five dogs died; larger reviews found most dogs survived with treatment, but some had severe fever and died. Keep hops and hop products away from dogs, and call a vet at once if a dog eats any.

Q: Is non-alcoholic beer or beer a good way to get the benefits?

No. Two small studies of non-alcoholic beer reported faster sleep onset but had no placebo drink. Beer contains many things besides hops, and alcoholic beer adds alcohol, which affects sleep, driving, pregnancy and medicines. In a lab test alcohol added to a hop compound's calming effect.

Q: Can hops cause an allergy?

Yes, in some people. Case reports describe skin and airborne reactions in hop farm workers and whole-body hives, and a herbal sedative and face cream with hop extract triggered one case. A lab study found hop proteins react with pollen antibodies. The EU lists allergy to the plant as the contraindication. How often it happens is unknown.

Humulus lupulus L. · also called Hops, common hop, hop cones (strobiles), lúpulo (Spanish), houblon (French), Hopfen (German)

Hops are the papery green cones of a climbing plant in the hemp family, best known for flavouring beer. The cones, their extracts and valerian-hops combinations are also sold for sleep, stress and menopause symptoms.

General information, not medical advice. Last substantive update October 25, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

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About Hops

Hops (Humulus lupulus) are best known for flavouring beer, and the cones are also used as a traditional herbal medicine for mild stress and to aid sleep. Research is limited: sleep trials mostly test valerian plus hops, a handful of small trials look at stress, menopause, belly fat and thinking, and the best-documented harms are drowsiness, plant-estrogen concerns and, in dogs, poisoning.

What it is

Hops (Humulus lupulus) are the female cones (strobiles) of a climbing plant in the Cannabaceae family. It is an accepted species in the GBIF and NCBI databases. It is related to cannabis but is a different plant.

The cones are used in brewing, and as a tea, extract or tincture. The EU monograph covers comminuted or powdered cone and its dry and liquid extracts.

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Traditional and current uses

The EU recognises hop strobile as a traditional herbal medicine for relief of mild mental stress and to aid sleep. This is based on long use, not on trial proof, and it advises seeing a doctor if symptoms last more than two weeks.

Modern uses go further: sleep (usually with valerian), menopause symptoms, appetite and weight, and mood. Evidence for these ranges from low to insufficient.

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What is in it and how it works

Hops contain bitter acids (humulone, lupulone), prenylated flavonoids (xanthohumol, isoxanthohumol, 6- and 8-prenylnaringenin) and oils. In lab tests humulone and 6-prenylnaringenin strengthen the brain's calming GABA-A receptors, and a valerian-hops extract acted on adenosine in a brain-wave test. These are lab clues, not proof of how hops work in people.

8-Prenylnaringenin is described as one of the most potent plant estrogens known; it can also be made in the gut from isoxanthohumol, and people differ widely in how much they make. Xanthohumol has been tested as a pure compound in small safety trials. Special processed extracts (matured hop bitter acids, bitter hop extract) are not the same as whole hops.

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What the research shows

Sleep: a 184-adult trial of a valerian-hops tablet found modest gains and few results that beat placebo; one trial found valerian-hops beat placebo where valerian alone did not. Stress and anxiety: one 36-person pilot. Menopause: small, mixed trials. Belly fat: one 200-person company-sponsored trial. Attention: two small trials from one group.

Many studies were small, short, open or company-linked, and only abstracts were read for almost every paper.

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At a glance

Traditional uses history, not proof

Traditional European herbal medicine: the female cones have long been used mainly for sleep problems (a review of the plant). The EU monograph (2014) accepts hop strobile as a traditional herbal medicine for mild mental stress and to aid sleep, based only on long use.
Brewing: hops give beer its bitterness, flavour and aroma. This is a food use, not a medicine claim.
Pharmacopoeias: hops are allowed in several official pharmacopoeias, mainly for anxiety states (a 2022 review).
German Commission E is reported by one trial's authors to approve hops for restlessness and anxiety; we did not read the monograph, so this is not verified.

Studied for research

Sleep problems (valerian-hops combinations), low
Stress, anxiety and low mood (hop extract), low
Attention and memory in older adults (matured hop bitter acids), low
Menopausal hot flashes (8-prenylnaringenin extracts), low, mixed
Belly fat and appetite (matured and bitter hop extracts), low
Blood fats, blood vessels, inflammation and gut (small studies), very low to insufficient

Main compounds

Xanthohumol, the main prenylated chalcone: anti-inflammatory and gut-bacteria effects in small human trials
8-Prenylnaringenin (8-PN), a very potent plant estrogen that can also form in the gut from isoxanthohumol
Humulone and lupulone (hop alpha and beta acids), bitter acids that calm GABA receptors in lab tests
Iso-alpha acids and matured hop bitter acids formed by heating or oxidising hops
Isoxanthohumol and 6-prenylnaringenin, related prenylflavonoids

Common forms

Dried cones or comminuted cones as a tea (hop tea)
Dry and liquid extracts and tinctures of the cone
Valerian-and-hops tablets and liquid combinations
Hop extracts standardised to 8-prenylnaringenin or to bitter acids
Beer and non-alcoholic beer (a different product, not a supplement)
Spent brewing hops (poisonous to dogs)

Research links: EU herbal monograph on hop strobile (European Medicines Agency, 2014) · EMA page: Lupuli flos herbal medicinal product · NIH LiverTox: Hops · Research Library · Genes & Biomarkers Library

The plant and its history

Accepted scientific name: Humulus lupulus L.
Naming authority: L.; published in Species Plantarum, page 1028 (1753) (GBIF)
Synonyms: Cannabis lupulus (L.) Scop.; Humulus vulgaris Gilib.; Humulus volubilis Salisb.; Humulus yunnanensis Hu (listed by GBIF as a synonym); Lupulus communis Gaertn.; Humulus lupulus var. silvestris Alef. and other varieties (GBIF list)
Common names: Hop (English); Hops (English); Common hop (English); Bine (English); Lúpulo (Spanish); Houblon (French); Hopfen (German)
Botanical family: Cannabaceae (the hemp family; it also holds Cannabis sativa L., GBIF key 5361880). Hops and cannabis are relatives but are different plants with different chemistry.
Classification: Plantae > Tracheophyta > Magnoliopsida > Rosales > Cannabaceae > Humulus > Humulus lupulus
Native range: Not verified from a primary botanical source in this file.
Habitat: Not verified.
What the plant looks like: Roots: Not verified; not the medicinal part.; Stems: Not verified in this file (a climbing plant is the usual description, but we did not confirm it from a source read).; Leaves: Not the medicinal part under the EU monograph.; Flowers: The female inflorescences, called cones or strobili, are the part used (a 2022 review).; Fruit: Not verified.
Cultivation: Not verified from a primary source; the plant is grown commercially for brewing (the reviews we read say hops are mainly a beer ingredient).
Harvest and processing: The EU monograph covers comminuted or powdered hop strobile and dry or liquid extracts or tinctures. "Spent hops" are the brewing leftovers that have poisoned dogs.
Look-alikes and adulterants: Name: Humulus japonicus Siebold & Zucc. (Japanese hop); Note: GBIF lists it as a synonym of Humulus scandens (Lour.) Merr. (key 2984537), a different species from the common hop. A lab abstract notes its hop-like allergen cross-reactivity was studied (not read here).; Name: Humulus yunnanensis Hu; Note: GBIF lists this name as a synonym of Humulus lupulus in its backbone.
Sustainability and conservation: Not verified; no assessment was retrieved. Hop is a widely cultivated plant.

The plant and the parts used

Dried hop cones (Humulus lupulus) next to a cup of hop tea — Dried hop cones, the part used, with a cup of hop tea.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
Traditional European herbal medicine	The female cones have long been used in traditional medicine mainly for sleep problems (a review of the plant's pharmacology). The EU monograph recognises hop strobile as a traditional herbal medicine for relief of mild symptoms of mental stress and to aid sleep.	s-ema-hmpc-hops
Beer brewing	Hops are a main ingredient of beer, giving bitterness, flavour and aroma (several abstracts).	p36559547
Pharmacopoeias	A 2022 review says hops are allowed in several official pharmacopoeias, mainly for anxiety states; and the Ph. Eur. monograph for hops (ref. 1/2011:1222) is cited by the EU monograph.	s-ema-hmpc-hops
German Commission E	Reported by a trial's authors to approve hops for restlessness and anxiety/mood disorders.	s-commission-e-hops
Older sources, Wikipedia and herbals	Stories such as hop pillows or hop pickers feeling sleepy are widely repeated; we did not verify them from a primary source and NOT verified applies to them.	p18308492

Traditional use shows how a plant was used. It does not show that a supplement works or is safe today.

What is inside, and how it may work

What the plant contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.

Main compounds

Compound	Family	Where it is concentrated	Activity studied	Level of evidence
Xanthohumol PubChem 639665	prenylated chalcone (prenylflavonoid)	Strobile Not stated in the abstracts read	Main hop prenylated chalcone; anti-inflammatory and gut-microbiome effects in human studies; safe at 24 mg a day for 8 weeks in 30 healthy adults. ^{35 29 30 36 43}	Human data
8-Prenylnaringenin (8-PN) PubChem 480764	prenylated flavanone	Strobile (small amounts); formed in the gut from isoxanthohumol Not stated in the abstracts read	Called one of the most potent plant estrogens; binds estrogen receptor alpha; blood level after 500 mg single dose Cmax 2,834 nmol/L. ^{10 31 9 43}	Human data
6-Prenylnaringenin (6-PN) PubChem 155094	prenylated flavanone	Strobile Not stated	Boosted GABA-A receptors in lab tests; less bioavailable than 8-PN (Cmax 543 vs 2,834 nmol/L). ^{4 10 43}	Laboratory research
Isoxanthohumol PubChem 513197	prenylated flavanone	Strobile; common in beer Not stated	Weakly estrogenic; turned into 8-PN by gut bacteria and liver CYP1A2; blocked CYP2C8 strongly in lab tests. ^{25 7 67 43}	Laboratory research
Humulone (alpha acid) PubChem 442911	prenylated phloroglucinol (bitter acid)	Strobile (lupulin glands) 35 to 70% of hop alpha acids (per an abstract)	Positive modulator of GABA-A receptors in lab tests; shortened sleep onset in mice at 20 mg/kg injected. ^{5 43}	Animal research
Lupulone (beta acid) PubChem 68051	bitter acid	Strobile Not stated	Named among hop bitter acids with sedative activity in animal work. ^{37 43}	Animal research
Isohumulones (iso-alpha acids) PubChem 93090	bitter acids formed by heating	Produced when hops are boiled in brewing Not stated	Absorbed fast (peak 0.5 h) with half-life about 30 minutes after beer; used in isomerised hop extract that widened arteries in a single-dose trial. ^{49 59 43}	Human data
Matured hop bitter acids	oxidised alpha-acid derivatives	Oxidised hop extract Not stated	Oxides derived from alpha acids, structurally like iso-alpha acids; studied at 35 mg a day for body fat, mood and cognition. ^{40 20}	Human data
2-Methyl-3-buten-2-ol PubChem 8257	small alcohol (alpha-acid breakdown product)	Formed on storage of hops Not stated	Proposed by one trial's authors as a sedative principle behind hops raising GABA; this is a hypothesis in their abstract, not tested there. ^{18 43}	Pharmacological theory

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
GABA-A receptor positive modulation	GABRA1 / GABA-A receptor	Humulone and 6-prenylnaringenin boosted GABA-A receptor activity at low micromolar concentrations; humulone shortened sleep onset and lengthened sleep in mice; ethanol added to the lab effect. ^{4 5 37}	Laboratory research
Adenosine receptor mechanism	ADORA1	A fixed valerian-hop extract reduced or blocked caffeine-induced brain-wave arousal in 32 healthy volunteers, read by the authors as an adenosine-related effect. ⁵²	Human data
Estrogen receptor activation	ESR1	8-prenylnaringenin binds and activates estrogen receptor alpha; it activated ERK signalling in breast cancer cells like estradiol but not the PI3K/Akt route, and slowed cell division in that cell model. ^{9 31}	Laboratory research
Estrogen metabolism in breast cells	CYP1A1 / CYP1B1 / AhR	Hop extract and 6-PN favoured the non-toxic 2-hydroxylation route via CYP1A1; hops also reduced 4-hydroxylation and estrogen-induced malignant change in MCF-10A cells. ^{65 26}	Laboratory research
Aromatase inhibition	CYP19A1	Xanthohumol, isoxanthohumol, 8-PN and several beers reduced aromatase activity in cell tests. ³⁹	Laboratory research
Drug-metabolising enzyme inhibition	CYP2C8 / CYP2C9 / CYP2C19 / CYP1A2	A hop extract blocked CYP2C8 (93%), CYP2C9 (88%), CYP2C19 (70%) and CYP1A2 (27%) at 5 micrograms/ml. ⁶⁷	Laboratory research
Glucuronidation (UGT) inhibition	UGT1A1 / UGT2B7	Valerian-hops extracts cut formation of acetaminophen, estradiol, morphine and testosterone glucuronides in human liver microsomes. ²	Laboratory research
Drug transporters	ABCB1 (P-glycoprotein) / ABCC1 (MRP1)	8-prenylnaringenin inhibited both pumps in human cell tests. ⁶⁶	Laboratory research
Bitter taste and gut hormones	Gut bitter receptors; CCK, GLP-1, PYY, ghrelin	A 500 mg bitter hop extract raised ghrelin, CCK, GLP-1 and PYY and lowered insulin response in 19 men; a tube-delivery trial found only modest PYY changes. ^{63 6}	Human data
Toll-like receptor 4 signalling	TLR4 / CD14	A xanthohumol-rich hop extract lowered toxin-induced inflammatory signalling in white blood cells taken from nine women and in transfected cells. ³⁰	Human data
Gut microbiota	Gut bacteria (Prevotella, Ruminococcus)	Xanthohumol 24 mg a day for 8 weeks did not change overall gut composition but changed some groups by gut type and reduced bile-acid metabolites in some. ²⁹	Human data

Absorption, metabolism and elimination

Absorption: Xanthohumol (single oral doses of 20, 60 or 180 mg in 48 people): peaked at about 1 hour and again at 4 to 5 hours; Cmax 33, 48 and 120 mg/L (as printed in the abstract); conjugates were the main forms in blood. 8-prenylnaringenin (single 500 mg of the pure compound in 16 people): Cmax 2,834 nmol/L and AUC 15,801 nmol/L x h, about 4 to 5 times higher than 6-PN. Iso-alpha acids from beer were absorbed quickly, with a peak at 0.5 h.
Distribution: No human tissue distribution data were found. In mice 8-PN reached kidney, liver, muscle, lung, pancreas, heart, spleen and brain, in higher amounts than the non-prenylated naringenin.
Metabolism: 8-PN: CYP2C19 and CYP2C8 oxidise the prenyl group; human liver microsomes made 12 metabolites. Isoxanthohumol is turned into 8-PN by CYP1A2 and by gut bacteria: in 50 postmenopausal women 60% were poor, 25% moderate and 15% strong 8-PN producers, and recent antibiotics seemed to lower production. Xanthohumol and isoxanthohumol travel mostly as glucuronide conjugates.
Elimination: Xanthohumol half-life was about 20 hours (60 mg) and 18 hours (180 mg). Iso-alpha acid half-life in beer drinkers was estimated at about 30 minutes in five volunteers. Elimination of hop extracts as a whole was not studied.
Bioavailability: Urinary recovery of hop flavonoids was low and varied widely between people; 8PN was undetectable in most people after xanthohumol dosing.

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Isolated compounds versus whole extracts

Hops are a mixture. The EU monograph covers whole strobile and its extracts, and the sleep trials used hop extract with valerian. In one trial valerian plus hops beat placebo while valerian alone did not, which suggests hops add something, but it cannot be tied to one compound. Lab work shows several compounds (humulone, 6-PN, xanthohumol) can calm brain receptors. The estrogen-like action comes mainly from 8-prenylnaringenin, which is present in small amounts in hops but can be made in the body from isoxanthohumol, and how much depends on each person's gut bacteria. Xanthohumol and 8-PN have been tested as pure compounds for safety and blood levels; those results should not be applied to hop tea or ordinary supplements. Matured hop bitter acids and bitter hop extracts for weight are special processed extracts, not whole hops.

Nutritional composition

A nutrient table does not apply: hops are used in small amounts as a flavouring and medicine, and we found no nutrient data in the sources read. Beer and non-alcoholic beer contain many other compounds besides hops, so trial results with beer are not hop-only results.

13benefits and uses looked at

69studies and sources checked

Low certaintybest evidence rating found

20lab markers tracked in trials

6 low certainty5 very low certainty2 not enough evidence

What was looked at

The 13 benefits and uses checked for Hops, each with how strong the evidence is. Tap one to open it.

Sleep problems: valerian-and-hops combination products (4 weeks)Low certainty
Falling asleep after a single dose of valerian-hops extractVery low certainty
Sleep after non-alcoholic beer (a drink with hops)Very low certainty
Stress, anxiety and low mood: hop dry extract in healthy young adultsLow certainty
Mood and tiredness: matured hop bitter acids in beer-type drinksVery low certainty
Attention and memory: matured hop bitter acids in older adultsLow certainty
Menopausal hot flashes and other menopause complaintsLow certainty
Sexual function after menopause (hop vaginal gel)Not enough evidence
Belly fat: matured hop extract in overweight adultsLow certainty
Appetite and weight loss: bitter hop extractLow certainty
Blood fats and insulin in metabolic syndrome (hop plus acacia)Very low certainty
Blood vessel widening after a hop bitter-acid extractVery low certainty
Inflammation and gut: xanthohumol (a hop compound)Not enough evidence

Lab markers tracked in the studies

Time to fall asleep (sleep latency)Sleep duration (wearable-tracked)Sleep amount on EEG (electrohypnogram)Morning cortisol (blood)Depression, anxiety and stress scores (DASS-21)Symbol Digit Modalities Test (attention score)Beta-endorphin (blood)Transthyretin (serum protein)Stroop test and verbal fluencyKupperman Menopausal IndexHot flash frequencyHormone profile and womb lining thicknessVisceral fat area (CT scan)Energy eaten at the next mealsGut hormones (ghrelin, CCK, GLP-1, PYY)Flow-mediated vasodilatation (FMD)Triglycerides and TG:HDL ratioFasting insulin and HOMA scoreInflammatory signals from white blood cells (ex vivo)Gamma-glutamyltransferase (GGT) and BMI

What is Hops good for?

The main proposed uses and how strong the human evidence is for each. "Low" means small or inconsistent studies, "very low" means one small, open or mixed-product study, and "insufficient" means there is not enough to judge. Nothing about hops is rated higher than low. Many results come from valerian-hops combinations, beer-type drinks, special oxidised extracts or pure compounds, which cannot be moved to ordinary hop tea or other products. For amounts, ask a doctor or pharmacist.

Sleep problems (valerian-and-hops products)Low certaintyMost sleep research on hops tests valerian and hops together. In 184 adults with mild insomnia (4 weeks) a valerian-hops tablet gave modest self-reported gains but few results beat placebo, and lab sleep recordings did not differ between groups. A second trial found valerian-hops shortened the time to fall asleep while valerian alone did not. A 40-person feasibility trial found about 22 more minutes of tracked sleep a day, and a one-night lab test found more sleep time. A review of 16 studies found 12 reported some benefit, with reviewers asking for better trials. Hops cannot be given credit separately, and no trial tested hops alone for insomnia. Sleep after a non-alcoholic beerVery low certaintyTwo small, open studies (17 shift-working nurses and 30 students) found people fell asleep faster after a non-alcoholic beer with dinner for 2 weeks. There was no placebo beer and beer contains many other substances, so hops cannot be credited. This does not apply to alcoholic beer. Stress, anxiety and low moodLow certaintyIn a 36-person crossover pilot of young adults with at least mild symptoms, anxiety, depression and stress scores fell more on 4 weeks of a hop dry extract than on placebo. Morning cortisol did not change. It has not been repeated, and people with a diagnosed anxiety or depressive disorder were not tested. Mood and tiredness with matured hop bitter acidsVery low certaintyAn uncontrolled 3-week study of a non-alcoholic beer with oxidised hop bitter acids found better mood, less fatigue and better sleep versus baseline, and a placebo-controlled trial found less fatigue and anxiety at 12 weeks. Both are linked to the brewer that makes the extract. Attention and memory in older adultsLow certaintyTwo 12-week trials (100 and 60 adults aged 45 and over who felt their thinking had slipped) found small gains in attention and some memory tests with matured hop bitter acids. Only some of many tests were significant, p-values were near 0.05, and both come from one research group. Menopausal hot flashes and other complaintsLow certaintySmall trials of hop extract (often standardised to 8-prenylnaringenin) give mixed results. One 67-woman trial beat placebo at 6 weeks but not 12; a 36-woman crossover pilot was not significant overall; a 120-woman Iranian trial reported very large benefits without naming the extract or dose in its abstract. A soy-hop combination beat placebo in 78 women. A review calls the human data few and inconclusive. Long-term effects on breast and womb are unknown. Sexual function after menopause (vaginal gel)Not enough evidenceOne trial of 63 postmenopausal women found no difference in sexual function scores between a hop vaginal gel and vaginal estradiol. There was no placebo group, so it does not show that hops work. Belly fat with matured hop extractLow certaintyA 200-person Japanese trial found less visceral fat on CT scans after 12 weeks of a matured hop extract drink than on placebo, with no related adverse events. The trial was sponsored by the maker, and a re-analysis of the same data is not a second trial. Appetite and weight loss with a bitter hop extractLow certaintyMen ate about 900 kJ less in a single-day capsule trial, but with stomach discomfort; a tube-delivery trial found no effect on appetite or intake; a 24-week trial of 150 adults found 3.8% more weight loss than placebo, but was linked to a supplement licence-holder and used bioimpedance, not a scan. Blood fats and insulin (hop plus acacia)Very low certaintyOne 12-week trial of a hop-acacia tablet in 104 adults with metabolic syndrome found greater falls in triglycerides and insulin resistance than placebo in the 3-tablet group. It is a mixed product and the abstract gives no numbers. Blood vessel widening after hop bitter acidsVery low certaintyA single-dose crossover test in 23 smokers and non-smokers found more artery widening 30 and 120 minutes after a hop bitter acid extract. It is a short-lived marker, not a heart outcome. Inflammation and gut (xanthohumol)Not enough evidencePure xanthohumol at 24 mg a day for 8 weeks was well tolerated in healthy adults and in 20 people with Crohn's disease; it changed some gut bacteria and calmed inflammatory signals in lab-tested blood cells, but no symptom or disease benefit has been shown.

Benefits, one by one

Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.

Sleep problems: valerian-and-hops combination products (4 weeks)

Low certainty

Most of the sleep research on hops tests a combination of valerian and hops, not hops alone. These trials show modest effects, and in the largest trial few results beat placebo.

5 studiesTablets or extracts of valerian plus hop dry extract. Dosing is not c…

Studies, doses and limits

What the trials found

Morin 2005: 184 adults with mild insomnia, 4 weeks of a valerian-hops tablet vs placebo vs diphenhydramine; subjective sleep improved modestly but few comparisons with placebo were significant, and lab sleep recordings showed no group differences; quality of life (physical) improved more with valerian-hops. Koetter 2007: a fixed valerian-hops combination cut sleep latency more than placebo, while valerian alone did not (abstract gives no participant number). Schicktanz 2025: a 40-person feasibility trial; exploratory finding of 21.7 more minutes of tracked sleep a day, no change in daytime thinking or mood. Salter 2010 reviewed 16 studies: 12 reported some sleep improvement with valerian alone or with hops, with reviewers asking for better trials.

Results

Modest and mixed. Subjective gains in some trials; objective lab-recorded sleep did not differ in the largest one.

Effect sizes as reported

Morin: modest, mostly not significant vs placebo. Koetter: sleep latency reduced vs placebo (no numbers in the abstract). Schicktanz: +21.7 min a day (p = 0.019, exploratory).

Why this rating

Small to medium trials of a combination product, some with weak design, mixed results and abstract-only reading. Hops cannot be given credit separately.

Form and dose studied

Tablets or extracts of valerian plus hop dry extract. Dosing is not covered here.

Who was studied

Adults with mild or occasional insomnia (mostly 40s).

Limits

Combination products only; hops-alone trials for insomnia are missing. Short (3 to 4 weeks). Two of the trials used the same branded extract (Ze 91019).

Why researchers looked

Hops and valerian are often sold together for sleep, so companies and universities tested the pair.

Traditional use

Hop cones (strobiles) have been used in European folk medicine for restlessness and poor sleep. The EU herbal monograph (2014) accepts them as a traditional herbal medicine for relief of mild symptoms of mental stress and to aid sleep, based only on long use, not on proof from trials. Hop pillows and hop-and-valerian preparations are old customs.

Proposed mechanism Preliminary mechanism

In lab tests hop compounds boost the brain's calming GABA-A receptors, and a valerian-hops extract acted on adenosine (a sleep-pressure chemical) in a brain-wave test in healthy volunteers. These are not proof of how it works in sleepers.

A proposed mechanism does not show that the effect happens in people.

Hops can make you sleepy. The EU monograph says it may impair the ability to drive and use machines. Full safety is in the safety section.

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Falling asleep after a single dose of valerian-hops extract

Very low certainty

One small lab study found more sleep time on the first night with a valerian-hops liquid extract; a brain-wave test also suggested a calming effect against caffeine.

2 studiesA liquid valerian-hops extract given once.

Studies, doses and limits

What the trials found

Dimpfel 2008: 20 poor sleepers on the extract vs 22 on placebo, one lab night; sleep time and deeper sleep were higher on the extract (p < 0.01). Schellenberg 2004: 16 people per group; the extract reduced or blocked caffeine arousal on EEG.

Results

Positive in small single-night experiments; no insomnia outcomes beyond one night.

Effect sizes as reported

Sleep quantity p < 0.01; EEG measure correlated with sleep rating r = 0.48.

Why this rating

One small single-night trial and one brain-wave test; non-standard EEG method; combination product.

Form and dose studied

A liquid valerian-hops extract given once.

Who was studied

Poor sleepers; healthy volunteers.

Limits

Single night only, 42 people, mixed product, no sleep-lab polysomnography.

Why researchers looked

Researchers wanted to know whether one dose is enough or whether the extract must be taken for weeks.

Traditional use

Proposed mechanism Preliminary mechanism

The authors link the effect to adenosine receptors; in healthy volunteers the extract reduced or blocked caffeine's brain-wave arousal at 60 minutes.

A proposed mechanism does not show that the effect happens in people.

Hops can make you sleepy. The EU monograph says it may impair the ability to drive and use machines. Full safety is in the safety section.

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Sleep after non-alcoholic beer (a drink with hops)

Very low certainty

Two small open studies found people fell asleep faster after a hop-containing non-alcoholic beer with dinner. There was no placebo beer, so the result is weak.

2 studiesOrdinary non-alcoholic beer with a meal.

Studies, doses and limits

What the trials found

Franco 2012: 17 female nurses on shifts, 333 ml non-alcoholic beer at supper for 14 days vs their own no-beer period; sleep latency 12.0 vs 20.5 minutes by wrist sensor (p <= 0.05). Franco 2014: 30 university students, one beer at dinner for 14 days vs a 7-day control week; sleep latency and global sleep score better (p < 0.05).

Results

Positive in two open, uncontrolled studies.

Effect sizes as reported

Sleep latency 12.01 vs 20.50 minutes (nurses).

Why this rating

No placebo drink, no blinding, small groups; beer contains many other compounds besides hops.

Form and dose studied

Ordinary non-alcoholic beer with a meal.

Who was studied

Healthy stressed young adults, shift-working nurses.

Limits

Not a hop extract trial; same research group; short. Does not apply to alcoholic beer, which affects sleep in other ways.

Why researchers looked

Beer is the best-known hop product, so researchers asked whether the hops in a non-alcoholic beer calm stressed people.

Traditional use

Brewers and herbalists have long said hops make people drowsy; the claim is old but not trial-tested in beer until recently.

Proposed mechanism Pharmacological theory

The authors suggest hop breakdown products raise GABA; this is not shown in these studies.

A proposed mechanism does not show that the effect happens in people.

Beer with alcohol is a different product. Alcohol can disturb sleep and mix badly with sedatives. Non-alcoholic beer still contains a trace of alcohol in some countries.

^{18 19}

Stress, anxiety and low mood: hop dry extract in healthy young adults

Low certainty

One small crossover trial found lower anxiety, depression and stress scores after 4 weeks of a hop extract, compared with placebo.

5 studiesHop dry extract capsules once a day.

Studies, doses and limits

What the trials found

Kyrou 2017: 36 healthy young adults (31 women) with at least mild symptoms on a 21-item questionnaire; 4 weeks of hop dry extract vs 4 weeks of placebo in a crossover. Scores fell more with hops (anxiety 9.2 to 5.1, depression 11.9 to 9.2, stress 19.1 to 11.6; p < 0.05 vs placebo). Morning cortisol did not change. A review of GABA-acting plants (Savage 2018) lists hops among ten plants with preclinical and clinical support, with no hops-specific figures in its abstract.

Results

Positive in one small trial; no replication found.

Effect sizes as reported

DASS-21 anxiety 9.2 to 5.1; depression 11.9 to 9.2; stress 19.1 to 11.6 (hops).

Why this rating

One 36-person crossover pilot, self-rated scales, young mostly female participants, 4 weeks, no second trial.

Form and dose studied

Hop dry extract capsules once a day.

Who was studied

Healthy university adults with mild symptoms.

Limits

Pilot; not people with a diagnosed anxiety or depression disorder; no long-term follow-up.

Why researchers looked

Hops are approved in Germany for restlessness and anxiety, and the trial tested that claim in people with mild symptoms.

Traditional use

Proposed mechanism Preliminary mechanism

GABA-A receptor boosting by humulone and 6-prenylnaringenin in lab tests; hop mixtures raised sleep time in mice. Not shown in people.

A proposed mechanism does not show that the effect happens in people.

If you are depressed, talk to a doctor before using a sedating herb. See safety.

^{34 51 4 5 37}

Mood and tiredness: matured hop bitter acids in beer-type drinks

Very low certainty

A Japanese brewer's research group found better mood and less tiredness after 3 weeks of a non-alcoholic beer with oxidised hop bitter acids, but the study had no control group.

2 studiesBeer-type drink or capsule with 35 mg matured hop bitter acids.

Studies, doses and limits

What the trials found

Fukuda 2022: 97 healthy adults in a single-arm study drank a non-alcoholic beer with 35 mg of matured hop bitter acids for 3 weeks; mood, anxiety, depression, fatigue, vigor, sleep quality and work performance improved vs baseline. Fukuda 2020 (JAFC): in a placebo-controlled trial of 60 adults, subjective fatigue (p = 0.008) and anxiety (p = 0.043) improved at 12 weeks with the bitter acids.

Results

Positive; the strongest design (the placebo-controlled one) shows smaller, p-value-borderline gains.

Effect sizes as reported

Fatigue p = 0.008, anxiety p = 0.043 (12-week trial).

Why this rating

One single-arm trial with no control and company funding; a small placebo-controlled trial with many outcomes tested.

Form and dose studied

Beer-type drink or capsule with 35 mg matured hop bitter acids.

Who was studied

Healthy adults 20 to 72.

Limits

Industry-linked (Kirin Holdings funded the 2022 study and holds patents). Not the same as ordinary hops or hop tea.

Why researchers looked

A brewing company developed a special oxidised hop extract and tested it for mood and mental tiredness.

Traditional use

The extract is a modern product, not a traditional one.

Proposed mechanism Animal research

The researchers propose that these bitter acids act through the vagus nerve (from mouse work); not shown in these trials.

A proposed mechanism does not show that the effect happens in people.

Not studied in people with mood disorders.

^{22 20}

Attention and memory: matured hop bitter acids in older adults

Low certainty

Two 12-week trials of an oxidised hop extract found small gains in attention and some memory tests in people aged 45 and over who felt their thinking had slipped. Both come from the same research group.

2 studiesCapsules with matured hop bitter acids (35 mg a day in one trial).

Studies, doses and limits

What the trials found

Fukuda 2020 (J Alzheimers Dis): 100 adults aged 45 to 69 with subjective cognitive decline took capsules or placebo for 12 weeks. Attention (Symbol Digit Modalities Test) was higher with the extract (p = 0.045); beta-endorphin lower (p = 0.043); transthyretin, a possible marker of mild cognitive impairment, higher (p = 0.048); memory retrieval improved in a subgroup. Fukuda 2020 (JAFC): 60 adults, 35 mg a day for 12 weeks; verbal fluency change at week 6 (p = 0.034) and Stroop test at week 12 (p = 0.019) improved.

Results

Small positive findings across tests; many tests, borderline p-values.

Effect sizes as reported

SDMT p = 0.045; verbal fluency p = 0.034; Stroop p = 0.019.

Why this rating

Two small, 12-week trials from one group, only some of many outcomes significant, subgroup analysis, funding not stated in the abstracts (the group is linked to Kirin Holdings in other papers).

Form and dose studied

Capsules with matured hop bitter acids (35 mg a day in one trial).

Who was studied

Healthy adults 45 to 69 with perceived cognitive decline.

Limits

Not people with diagnosed dementia; no independent replication.

Why researchers looked

Mouse work suggested these bitter acids might protect thinking, so the group tested adults with subjective cognitive decline.

Traditional use

No traditional use for this; it is a new use of a modern extract.

Proposed mechanism Animal research

In mice the authors link the effect to vagus-nerve activation; this is not shown in the human trials.

A proposed mechanism does not show that the effect happens in people.

No safety problems were noted in the abstracts.

^{21 20}

Menopausal hot flashes and other menopause complaints

Low certainty

Small trials of hop extract (mostly standardised to 8-prenylnaringenin) show fewer menopause symptoms than placebo in some trials and not in others. The results are inconsistent and the trials are small.

7 studiesHop extracts standardised to 8-prenylnaringenin, tablets of hop extra…

Studies, doses and limits

What the trials found

Heyerick 2006: 67 menopausal women, 12 weeks; everyone improved, including placebo; the lower-dose hop group beat placebo at 6 weeks (p = 0.023) but not at 12 weeks (p = 0.086); the higher dose did worse than the lower one. Erkkola 2010: 36 women, 16-week crossover; overall effect not significant, later-period differences significant for Kupperman index (p = 0.02) and visual scale (p = 0.03). Aghamiri 2016: 120 women, 12 weeks; Greene score fell 23.4 points more and hot flashes 23.8 fewer than placebo at week 12 (very large numbers; extract and dose not stated in the abstract). Kim 2021: 78 women with moderate to severe symptoms, a combined soy and hop extract for 12 weeks; Kupperman score fell 20.6 vs 14.8 points with placebo (p < 0.05); combination, so hops cannot be credited alone. Trius-Soler 2021: 6 months of beer (alcoholic or non-alcoholic) lowered symptom scores vs a no-beer group in 34 women; beer is not a hop extract. Keiler 2013 calls human data few and inconclusive; Chadwick 2006 found only two menopause trials up to 2003.

Results

Mixed: positive in some small trials, inconclusive in others, large placebo responses.

Effect sizes as reported

Heyerick: p = 0.023 at 6 weeks, p = 0.086 at 12 weeks (100 microgram group). Aghamiri: Greene -23.4 (CI -25.1 to -21.6). Kim: -20.6 vs -14.8 points.

Why this rating

Four small trials (36 to 120 women) with large placebo effects, inconsistent dose response, one very large effect from a single centre, and one trial of a soy-hop combination. No hot-flash trial longer than 12 weeks.

Form and dose studied

Hop extracts standardised to 8-prenylnaringenin, tablets of hop extract, and a soy-hop combination. Dosing is not covered here.

Who was studied

Menopausal and postmenopausal women.

Limits

Short follow-up, small, mixed extracts. Long-term effect on breast and womb tissue is unknown.

Why researchers looked

8-prenylnaringenin (8-PN) is one of the strongest plant estrogens identified, so researchers tested hop extracts for hot flashes.

Traditional use

The EU herbal monograph does not list menopause as a traditional use of hops; its only traditional indication is mild mental stress and sleep. Interest in menopause comes from modern lab findings on 8-prenylnaringenin.

Proposed mechanism Animal research

8-PN binds estrogen receptors, preferring the alpha type; in animals it lowered LH and FSH and raised uterine weight. Human relevance of these animal findings for hot flashes is not proven.

A proposed mechanism does not show that the effect happens in people.

Hops contain 8-prenylnaringenin, one of the strongest plant estrogens known. See the safety section before using hop products if you have a hormone-sensitive condition.

^{28 17 1 32 60 31 12}

Sexual function after menopause (hop vaginal gel)

Not enough evidence

One Iranian trial found no difference in sexual function scores between a hop vaginal gel and vaginal estradiol cream, but there was no placebo group.

1 studiesA vaginal gel with hop extract (not a swallowed product).

Studies, doses and limits

What the trials found

Vahedpoorfard 2023: 63 postmenopausal women; a hop gel (daily for 7 days, then twice weekly for 2 months) vs vaginal estradiol; Female Sexual Function Index scores did not differ between groups and no adverse events were reported.

Results

No difference from estradiol; no placebo comparison.

Effect sizes as reported

FSFI total and subscales: no significant difference (p > 0.05).

Why this rating

One 63-person trial with no placebo; no difference from estradiol does not show that hop works.

Form and dose studied

A vaginal gel with hop extract (not a swallowed product).

Who was studied

Postmenopausal women with sexual dysfunction.

Limits

No placebo group; 2-month follow-up; one centre.

Why researchers looked

Low estrogen after menopause can dry and thin the vaginal lining; hop is a plant estrogen, so a gel was tested against estradiol.

Traditional use

No traditional use is documented for this in the EU herbal monograph; it is a modern research idea.

Proposed mechanism Pharmacological theory

Plant estrogen action on vaginal tissue is the proposed route; not proven in this trial.

A proposed mechanism does not show that the effect happens in people.

Hop is an estrogen-like plant: a vaginal gel could have effects on the breast or womb that this trial did not look at.

⁶¹

Belly fat: matured hop extract in overweight adults

Low certainty

A 200-person Japanese trial found less visceral (belly) fat after 12 weeks of a matured hop extract drink than placebo. The trial was sponsored by a brewer.

2 studiesA drink with matured hop extract (35 mg bitter acids a day).

Studies, doses and limits

What the trials found

Morimoto-Kobayashi 2016: 200 healthy adults with BMI 25 to under 30, drink with 35 mg matured hop bitter acids vs placebo for 12 weeks; visceral fat area (CT scan) fell more with hops at 8 and 12 weeks, and total fat area at 12 weeks; body fat ratio fell; no related adverse events. Suzuki 2018: re-analysis of the same data; visceral fat change correlated with daily steps in the hop group (r = -0.208, p = 0.048); the effect of hops combined with walking was borderline (p = 0.055).

Results

Positive in one trial; a re-analysis of the same trial is not an independent result.

Effect sizes as reported

Visceral and total fat area lower than placebo (numbers not in the abstract).

Why this rating

One well-sized trial from one company; no independent replication; Japanese adults only; 12 weeks; the second paper uses the same data.

Form and dose studied

A drink with matured hop extract (35 mg bitter acids a day).

Who was studied

Healthy overweight adults aged 20 to 64.

Limits

Company-sponsored; healthy overweight (not obese or diabetic) adults; no long-term follow-up.

Why researchers looked

Hop bitter acids called iso-alpha acids were reported in earlier work to reduce body fat; a milder oxidised extract was tested.

Traditional use

No traditional use is documented for this in the EU herbal monograph; it is a modern research idea.

Proposed mechanism Animal research

Bitter hop acids may act on fat metabolism and on receptors that regulate sugar and fat; the human relevance of this is not shown here.

A proposed mechanism does not show that the effect happens in people.

No related adverse events in the trial. Product-maker links are noted in the studies.

^{40 56}

Appetite and weight loss: bitter hop extract

Low certainty

A gut-hormone trial found that men ate less after a bitter hop extract, but a second gut trial found no effect on appetite, and a 24-week weight-loss trial reported more fat loss than placebo.

4 studiesBitter hop extract capsules (an unusual, very bitter extract, not hop…

Studies, doses and limits

What the trials found

Walker 2022: 19 healthy-weight men; 500 mg bitter hop extract capsules lowered energy intake (about 4,470 kJ vs 5,383 kJ placebo, p = 0.004 to 0.006) and changed gut hormones; stomach and bowel discomfort rose, with mild to severe symptoms with the quick-release capsule. Bitarafan 2023: 26 men; hop extract delivered by tube into the duodenum or stomach had no effect on appetite, symptoms or energy intake, and only a modest, short effect on pyloric pressure and PYY at the higher dose. Walker 2019: 30 men, 24-hour water fast; hunger over 10% lower in the last 6 hours with either dose (p < 0.05). Walker 2026: 150 adults, 24-week weight-loss programme; 3.8% more weight loss and 3.9 kg more fat loss than placebo (p < 0.05), muscle mass unchanged by bioimpedance.

Results

Mixed: positive in capsule trials, negative in the tube trial; the longest trial is positive but from the product's licence holder.

Effect sizes as reported

Energy intake 4,473 and 4,439 kJ vs 5,383 kJ (Walker 2022); weight -3.8% and fat mass -3.9 kg vs placebo (Walker 2026).

Why this rating

Small acute trials in men, one negative trial, one 24-week trial using bioimpedance, and a licensing link between the research institute and the supplement maker.

Form and dose studied

Bitter hop extract capsules (an unusual, very bitter extract, not hop tea).

Who was studied

Healthy-weight men; adults with overweight or obesity.

Limits

Mostly men; short; the weight-loss trial is the only longer one; unblinded stomach effects may unmask the capsule.

Why researchers looked

Bitter tastes can trigger hormones from the gut that signal fullness; hop extract is very bitter.

Traditional use

No traditional use is documented for this in the EU herbal monograph; it is a modern research idea.

Proposed mechanism Preliminary mechanism

Bitter receptors in the gut lining can release hormones such as CCK, GLP-1 and PYY; this was measured in the first trial.

A proposed mechanism does not show that the effect happens in people.

Stomach discomfort, nausea and bloating were reported in the first trial.

^{63 6 62 64}

Blood fats and insulin in metabolic syndrome (hop plus acacia)

Very low certainty

One 12-week trial of a combination of hop iso-alpha acids and acacia extract found lower triglycerides and insulin resistance than placebo in the 3-tablet group. It is a mixed product, so hops cannot be credited alone.

1 studiesTablets with hop rho-iso-alpha acids and acacia proanthocyanidins.

Studies, doses and limits

What the trials found

Minich 2010: 104 adults with metabolic syndrome took tablets with 100 mg hop rho-iso-alpha acids plus 500 mg acacia proanthocyanidins (3 or 6 a day) or placebo for 12 weeks; the 3-tablet group had greater falls in triglycerides, TG:HDL ratio, fasting insulin and HOMA score than placebo.

Results

Positive in one trial of a combination product.

Effect sizes as reported

Greater reductions than placebo; numbers not in the abstract.

Why this rating

One trial, combination product, abstract has no numbers or funding statement.

Form and dose studied

Tablets with hop rho-iso-alpha acids and acacia proanthocyanidins.

Who was studied

Adults with metabolic syndrome.

Limits

Cannot say whether hop or acacia did the work; no independent trial found.

Why researchers looked

Hop iso-alpha acids were reported in cell and animal work to affect insulin signalling.

Traditional use

No traditional use is documented for this in the EU herbal monograph; it is a modern research idea.

Proposed mechanism Laboratory research

In cells and mice the combination changed fat storage and insulin signalling.

A proposed mechanism does not show that the effect happens in people.

Not studied with diabetes or lipid medicines.

³⁸

Blood vessel widening after a hop bitter-acid extract

Very low certainty

In one small crossover test, the arteries of smokers and non-smokers widened more 30 and 120 minutes after a dose of hop bitter acids than after placebo.

1 studiesA single dose of isomerised hop extract (iso-alpha acids).

Studies, doses and limits

What the trials found

Tomita 2017: 12 smokers and 11 non-smokers took an isomerised hop extract and placebo in random order; flow-mediated vasodilatation increased 30 and 120 minutes after the extract in both groups.

Results

Positive acute change; no long-term outcome.

Effect sizes as reported

FMD higher at 30 and 120 min (p-values not in the abstract).

Why this rating

One small single-dose crossover trial; a short-lived measurement of artery function, not a heart outcome.

Form and dose studied

A single dose of isomerised hop extract (iso-alpha acids).

Who was studied

Smokers and non-smokers, 23 people.

Limits

Acute test; surrogate marker.

Why researchers looked

Smoking damages the lining of blood vessels; hop iso-alpha acids have antioxidant activity in the lab.

Traditional use

No traditional use is documented for this in the EU herbal monograph; it is a modern research idea.

Proposed mechanism Laboratory research

In cultured blood-vessel cells the extract reduced oxidative stress and protected against low-oxygen damage.

A proposed mechanism does not show that the effect happens in people.

None noted in the abstract.

⁵⁹

Inflammation and gut: xanthohumol (a hop compound)

Not enough evidence

Small human trials of pure xanthohumol so far test safety and gut bacteria, not health benefits. One single-dose study found calmer inflammatory signals in white blood cells in the lab.

4 studiesPure xanthohumol capsules or a xanthohumol-rich hop extract.

Studies, doses and limits

What the trials found

Langley 2021: 30 healthy adults, 24 mg a day for 8 weeks of pure xanthohumol vs placebo; no clinically relevant differences in lab tests, weight or quality of life. Jamieson 2024: the same trial; some bacteria changed by gut type, no change in overall composition. Jung 2022: 9 women, one tiny dose in a hop extract; white blood cells challenged with bacterial toxin in the lab released fewer inflammatory signals. Bradley 2026: 20 adults with Crohn's disease, 24 mg a day for 8 weeks; well tolerated; BMI and GGT differed from placebo; disease-activity result not given in the abstract.

Results

No clinical benefit shown; safety and lab findings only.

Effect sizes as reported

Crohn's trial: BMI -0.67 (p = 0.04), GGT -4.8 U/L (p = 0.02).

Why this rating

Early safety trials (first-stage and second-stage) with 9 to 30 people; no symptoms or disease outcome reported; pure xanthohumol, not hop tea or ordinary extracts.

Form and dose studied

Pure xanthohumol capsules or a xanthohumol-rich hop extract.

Who was studied

Healthy adults; adults with Crohn's disease.

Limits

Safety-focused; very small; not hops as sold for sleep.

Why researchers looked

Xanthohumol is the main prenylated chalcone in hops and shows anti-inflammatory activity in cell and animal work.

Traditional use

No traditional use is documented for this in the EU herbal monograph; it is a modern research idea.

Proposed mechanism Preliminary mechanism

Xanthohumol dampened toll-like receptor 4 signalling in lab-tested white blood cells; in people it shaped some gut-bacteria groups depending on each person's gut type.

A proposed mechanism does not show that the effect happens in people.

No serious adverse events in the 8-week trials.

^{35 29 30 8}

Connections to the rest of health

How Hops connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.

Explore every connection: goals, body systems, organs, symptoms, genes

Kind of connection Connected to Search

A. Wellness goals

Connected to	Kind of connection	Evidence status	Context	Studies
Better sleep	Potential benefit	Low certainty	Modest effects; sedation is also the main safety issue. Sleep problems: valerian-and-hops combination products (4 weeks): Most of the sleep research on hops tests a combination of valerian and hops, not hops alone. These trials show modest effects, and in the largest trial few results beat placebo. Preparation or compound: Valerian-hops combinations	^{41 33 16 53 50 13 52 18 19}
Menopause support	Potential benefit	Low certainty	Small, mixed trials for hot flashes and menopause symptom scores. Menopausal hot flashes and other menopause complaints: Small trials of hop extract (mostly standardised to 8-prenylnaringenin) show fewer menopause symptoms than placebo in some trials and not in others. The results are inconsistent and the trials are small. Preparation or compound: Hop extract standardised to 8-prenylnaringenin; soy-hop combination	^{28 17 1 32 60 31 12 61}
Anxiety support	Potential benefit	Low certainty	One 36-person crossover pilot found lower anxiety, depression and stress scores. Stress, anxiety and low mood: hop dry extract in healthy young adults: One small crossover trial found lower anxiety, depression and stress scores after 4 weeks of a hop extract, compared with placebo. Preparation or compound: Hop dry extract	^{34 51 4 5 37}
Weight management	Potential benefit	Low certainty	One 200-person belly-fat trial and mixed appetite trials; industry-linked. Belly fat: matured hop extract in overweight adults: A 200-person Japanese trial found less visceral (belly) fat after 12 weeks of a matured hop extract drink than placebo. The trial was sponsored by a brewer. Preparation or compound: Matured hop extract; bitter hop extract	^{40 63 6 64 56 62}
Sleep Quality	Potential benefit	Low certainty	Sleep problems: valerian-and-hops combination products (4 weeks): Most of the sleep research on hops tests a combination of valerian and hops, not hops alone. These trials show modest effects, and in the largest trial few results beat placebo. Sleep after non-alcoholic beer (a drink with hops): Two small open studies found people fell asleep faster after a hop-containing non-alcoholic beer with dinner. There was no placebo beer, so the result is weak.	^{41 33 53 50 16 18 19}
Calm Relaxation	Potential benefit	Very low certainty	Falling asleep after a single dose of valerian-hops extract: One small lab study found more sleep time on the first night with a valerian-hops liquid extract; a brain-wave test also suggested a calming effect against caffeine. Stress, anxiety and low mood: hop dry extract in healthy young adults: One small crossover trial found lower anxiety, depression and stress scores after 4 weeks of a hop extract, compared with placebo.	^{13 52 34 51 4 5 37}
Stress Reduction	Potential benefit	Low certainty	Stress, anxiety and low mood: hop dry extract in healthy young adults: One small crossover trial found lower anxiety, depression and stress scores after 4 weeks of a hop extract, compared with placebo. Mood and tiredness: matured hop bitter acids in beer-type drinks: A Japanese brewer's research group found better mood and less tiredness after 3 weeks of a non-alcoholic beer with oxidised hop bitter acids, but the study had no control group.	^{34 51 4 5 37 22 20}
Mood Balance	Potential benefit	Low certainty	Stress, anxiety and low mood: hop dry extract in healthy young adults: One small crossover trial found lower anxiety, depression and stress scores after 4 weeks of a hop extract, compared with placebo. Mood and tiredness: matured hop bitter acids in beer-type drinks: A Japanese brewer's research group found better mood and less tiredness after 3 weeks of a non-alcoholic beer with oxidised hop bitter acids, but the study had no control group.	^{34 51 4 5 37 22 20}
Reduce Fatigue	Potential benefit	Very low certainty	Mood and tiredness: matured hop bitter acids in beer-type drinks: A Japanese brewer's research group found better mood and less tiredness after 3 weeks of a non-alcoholic beer with oxidised hop bitter acids, but the study had no control group.	^{22 20}
Cognitive Performance	Potential benefit	Low certainty	Attention and memory: matured hop bitter acids in older adults: Two 12-week trials of an oxidised hop extract found small gains in attention and some memory tests in people aged 45 and over who felt their thinking had slipped. Both come from the same research group.	^{21 20}
Memory Support	Potential benefit	Low certainty	Attention and memory: matured hop bitter acids in older adults: Two 12-week trials of an oxidised hop extract found small gains in attention and some memory tests in people aged 45 and over who felt their thinking had slipped. Both come from the same research group.	^{21 20}
Mental Clarity	Potential benefit	Low certainty	Attention and memory: matured hop bitter acids in older adults: Two 12-week trials of an oxidised hop extract found small gains in attention and some memory tests in people aged 45 and over who felt their thinking had slipped. Both come from the same research group.	^{21 20}
Brain Health	Potential benefit	Low certainty	Attention and memory: matured hop bitter acids in older adults: Two 12-week trials of an oxidised hop extract found small gains in attention and some memory tests in people aged 45 and over who felt their thinking had slipped. Both come from the same research group.	^{21 20}
Womens Wellness	Potential benefit	Low certainty	Menopausal hot flashes and other menopause complaints: Small trials of hop extract (mostly standardised to 8-prenylnaringenin) show fewer menopause symptoms than placebo in some trials and not in others. The results are inconsistent and the trials are small. Sexual function after menopause (hop vaginal gel): One Iranian trial found no difference in sexual function scores between a hop vaginal gel and vaginal estradiol cream, but there was no placebo group.	^{28 17 1 32 60 31 12 61}
Hormone Balance	Potential benefit	Low certainty	Menopausal hot flashes and other menopause complaints: Small trials of hop extract (mostly standardised to 8-prenylnaringenin) show fewer menopause symptoms than placebo in some trials and not in others. The results are inconsistent and the trials are small.	^{28 17 1 32 60 31 12}
Libido Support	Potential benefit	Not enough evidence	Sexual function after menopause (hop vaginal gel): One Iranian trial found no difference in sexual function scores between a hop vaginal gel and vaginal estradiol cream, but there was no placebo group.	⁶¹
Metabolic Health	Potential benefit	Low certainty	Belly fat: matured hop extract in overweight adults: A 200-person Japanese trial found less visceral (belly) fat after 12 weeks of a matured hop extract drink than placebo. The trial was sponsored by a brewer. Appetite and weight loss: bitter hop extract: A gut-hormone trial found that men ate less after a bitter hop extract, but a second gut trial found no effect on appetite, and a 24-week weight-loss trial reported more fat loss than placebo.	^{40 56 63 6 62 64 38}
Digestive Support	Potential benefit	Low certainty	Appetite and weight loss: bitter hop extract: A gut-hormone trial found that men ate less after a bitter hop extract, but a second gut trial found no effect on appetite, and a 24-week weight-loss trial reported more fat loss than placebo. Inflammation and gut: xanthohumol (a hop compound): Small human trials of pure xanthohumol so far test safety and gut bacteria, not health benefits. One single-dose study found calmer inflammatory signals in white blood cells in the lab.	^{63 6 62 64 35 29 30 8}
Blood Sugar Balance	Potential benefit	Very low certainty	Blood fats and insulin in metabolic syndrome (hop plus acacia): One 12-week trial of a combination of hop iso-alpha acids and acacia extract found lower triglycerides and insulin resistance than placebo in the 3-tablet group. It is a mixed product, so hops cannot be credited alone.	³⁸
Cholesterol Balance	Potential benefit	Very low certainty	Blood fats and insulin in metabolic syndrome (hop plus acacia): One 12-week trial of a combination of hop iso-alpha acids and acacia extract found lower triglycerides and insulin resistance than placebo in the 3-tablet group. It is a mixed product, so hops cannot be credited alone.	³⁸
Heart Health	Potential benefit	Very low certainty	Blood vessel widening after a hop bitter-acid extract: In one small crossover test, the arteries of smokers and non-smokers widened more 30 and 120 minutes after a dose of hop bitter acids than after placebo.	⁵⁹
Healthy Aging	Potential benefit	Very low certainty	Blood vessel widening after a hop bitter-acid extract: In one small crossover test, the arteries of smokers and non-smokers widened more 30 and 120 minutes after a dose of hop bitter acids than after placebo.	⁵⁹
Inflammation Balance	Potential benefit	Not enough evidence	Inflammation and gut: xanthohumol (a hop compound): Small human trials of pure xanthohumol so far test safety and gut bacteria, not health benefits. One single-dose study found calmer inflammatory signals in white blood cells in the lab.	^{35 29 30 8}
Gut Health	Potential benefit	Not enough evidence	Inflammation and gut: xanthohumol (a hop compound): Small human trials of pure xanthohumol so far test safety and gut bacteria, not health benefits. One single-dose study found calmer inflammatory signals in white blood cells in the lab.	^{35 29 30 8}

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Reproductive system	Contraindication	Very low certainty	Estrogenic activity; caution with hormone-sensitive conditions; no long-term human data. Preparation or compound: 8-prenylnaringenin (plant estrogen)	^{31 9 69}
Digestive system	Adverse effect or risk	Low certainty	Nausea, bloating and discomfort in a single-dose trial of 19 men. Preparation or compound: Bitter hop extract 500 mg	⁶³
Nervous System	Biological association	Low certainty	Studied for: Sleep problems: valerian-and-hops combination products (4 weeks) Studied for: Falling asleep after a single dose of valerian-hops extract	^{41 33 53 50 16 13 52 34 51 4 5 37 22 20 21}
Sleep Recovery	Biological association	Low certainty	Studied for: Sleep problems: valerian-and-hops combination products (4 weeks) Studied for: Falling asleep after a single dose of valerian-hops extract	^{41 33 53 50 16 13 52 18 19}
Stress Mood	Biological association	Low certainty	Studied for: Stress, anxiety and low mood: hop dry extract in healthy young adults Studied for: Mood and tiredness: matured hop bitter acids in beer-type drinks	^{34 51 4 5 37 22 20}
Reproductive System	Biological association	Low certainty	Studied for: Menopausal hot flashes and other menopause complaints Studied for: Sexual function after menopause (hop vaginal gel)	^{28 17 1 32 60 31 12 61}
Endocrine System	Biological association	Low certainty	Studied for: Menopausal hot flashes and other menopause complaints	^{28 17 1 32 60 31 12}
Metabolism Weight	Biological association	Low certainty	Studied for: Belly fat: matured hop extract in overweight adults Studied for: Appetite and weight loss: bitter hop extract	^{40 56 63 6 62 64 38}
Digestive System	Biological association	Low certainty	Studied for: Appetite and weight loss: bitter hop extract Studied for: Inflammation and gut: xanthohumol (a hop compound)	^{63 6 62 64 35 29 30 8}
Cardiovascular System	Biological association	Very low certainty	Studied for: Blood fats and insulin in metabolic syndrome (hop plus acacia) Studied for: Blood vessel widening after a hop bitter-acid extract	^{38 59}
Immune System	Biological association	Not enough evidence	Studied for: Inflammation and gut: xanthohumol (a hop compound)	^{35 29 30 8}

C. Body parts and organs

Connected to	Kind of connection	Evidence status	Context	Studies
Brain	Adverse effect or risk	Very low certainty	Calming (sedating) effect on GABA-A receptors in lab tests; the EU monograph says driving may be impaired. Preparation or compound: Hop extracts, humulone, 6-prenylnaringenin	^{4 5 16}
Reproductive organs (breast and womb)	Biological association	Very low certainty	Cell tests show mixed signals (receptor activation and slowed growth); 12-week trials saw no change in womb lining thickness. Preparation or compound: 8-PN, hop extract	^{9 26 32}
Skin	Adverse effect or risk	Very low certainty	Contact and airborne dermatitis in hop workers; hop extract in a cream was an allergen source. Preparation or compound: Fresh and dried hop cones and leaves	^{55 48}
Airways	Adverse effect or risk	Very low certainty	Cross-reactivity with pollen allergens in lab tests; conjunctivitis and airborne dermatitis reported in workers. Preparation or compound: Hop pollen and plant protein	^{47 55}
Liver	Biological association	Very low certainty	No human liver injury reported; LiverTox rating is E per a search summary. Preparation or compound: Xanthohumol, hops	^{44 35 14}

G. Root causes and contributing factors

Connected to	Kind of connection	Evidence status	Context	Studies
Medication interactions	Drug or supplement interaction	Very low certainty	In-vitro enzyme and transporter inhibition; theory-based sedative stacking. Preparation or compound: Hop extracts	^{67 66 2}

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
CYP2C9 enzyme	Drug or supplement interaction	Very low certainty	Strong inhibition in human enzyme tests; no human interaction study. Preparation or compound: Hop extract, 8-PN, isoxanthohumol	⁶⁷
CYP2C19 enzyme	Drug or supplement interaction	Very low certainty	Inhibition in human enzyme tests and a route of 8-PN metabolism. Preparation or compound: Hop extract, 8-PN	^{67 25}
Estrogen	Biological association	Very low certainty	Strong plant estrogen in lab tests; no hormone change in two short trials. Preparation or compound: 8-prenylnaringenin	^{32 60 31}
Time to fall asleep (sleep latency)	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{33 18 19 41}
Sleep duration (wearable-tracked)	Biological association	Very low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	⁵³
Sleep amount on EEG (electrohypnogram)	Biological association	Very low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	¹³
Morning cortisol (blood)	Biological association	Low certainty	Measured in trials: no-change. A lab change is not the same as a health benefit.	³⁴
Depression, anxiety and stress scores (DASS-21)	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	³⁴
Symbol Digit Modalities Test (attention score)	Biological association	Low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	²¹
Beta-endorphin (blood)	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	²¹
Transthyretin (serum protein)	Biological association	Very low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	²¹
Stroop test and verbal fluency	Biological association	Low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	²⁰
Kupperman Menopausal Index	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{28 17 32}
Hot flash frequency	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{1 28}
Hormone profile and womb lining thickness	Biological association	Low certainty	Measured in trials: no-change. A lab change is not the same as a health benefit.	^{32 60}
Visceral fat area (CT scan)	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{40 56}
Energy eaten at the next meals	Biological association	Very low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	^{63 6}
Gut hormones (ghrelin, CCK, GLP-1, PYY)	Biological association	Low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	^{63 6}
Flow-mediated vasodilatation (FMD)	Biological association	Very low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	⁵⁹
Triglycerides and TG:HDL ratio	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	³⁸
Fasting insulin and HOMA score	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	³⁸
Inflammatory signals from white blood cells (ex vivo)	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	³⁰
Gamma-glutamyltransferase (GGT) and BMI	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁸

J. Genes, receptors and enzymes

Connected to	Kind of connection	Evidence status	Context	Studies
ESR1 (estrogen receptor alpha)	Preliminary mechanism	In vitro	Activated by 8-prenylnaringenin in breast cell tests.	^{9 31}
GABRA1 / GABA-A receptor	Preliminary mechanism	In vitro	Positive modulation by humulone and 6-PN in lab tests.	^{4 5}
CYP2C9	Preliminary mechanism	In vitro	Inhibited 88% by hop extract at 5 micrograms/ml.	⁶⁷
CYP2C19	Preliminary mechanism	In vitro	Inhibited 70%; also metabolises 8-PN.	^{67 25}
CYP2C8	Preliminary mechanism	In vitro	Inhibited 93%; metabolises 8-PN.	^{67 25}
CYP1A2	Preliminary mechanism	In vitro	Inhibited 27%; makes 8-PN from isoxanthohumol.	^{67 25}
CYP1A1	Preliminary mechanism	In vitro	Induced by hop extract and 6-PN via AhR in breast cells.	⁶⁵
CYP19A1 (aromatase)	Preliminary mechanism	In vitro	Activity reduced by hop prenylflavonoids in cells.	³⁹
ABCB1 (P-glycoprotein) and ABCC1 (MRP1)	Preliminary mechanism	In vitro	Inhibited by 8-PN.	⁶⁶
UGT1A1 and UGT2B7	Preliminary mechanism	In vitro	Reduced activity with valerian-hop extracts.	²
TLR4 and CD14	Preliminary mechanism	Human	Xanthohumol-rich extract lowered signalling in blood cells.	³⁰

K. Biological pathways

Connected to	Kind of connection	Evidence status	Context	Studies
Adenosine signalling	Preliminary mechanism	Human	Valerian-hop extract opposed caffeine arousal on EEG.	⁵²
Gut hormone release (CCK, GLP-1, PYY, ghrelin)	Preliminary mechanism	Human	Changed after a bitter hop extract.	⁶³

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Xanthohumol	Biological association	Human	Main hop prenylated chalcone; anti-inflammatory and gut-microbiome effects in human studies; safe at 24 mg a day for 8 weeks in 30 healthy adults. Preparation or compound: Strobile	^{35 29 30 36 43}
8-Prenylnaringenin (8-PN)	Biological association	Human	Called one of the most potent plant estrogens; binds estrogen receptor alpha; blood level after 500 mg single dose Cmax 2,834 nmol/L. Preparation or compound: Strobile (small amounts); formed in the gut from isoxanthohumol	^{10 31 9 43}
6-Prenylnaringenin (6-PN)	Biological association	In vitro	Boosted GABA-A receptors in lab tests; less bioavailable than 8-PN (Cmax 543 vs 2,834 nmol/L). Preparation or compound: Strobile	^{4 10 43}
Isoxanthohumol	Biological association	In vitro	Weakly estrogenic; turned into 8-PN by gut bacteria and liver CYP1A2; blocked CYP2C8 strongly in lab tests. Preparation or compound: Strobile; common in beer	^{25 7 67 43}
Humulone (alpha acid)	Biological association	Animal	Positive modulator of GABA-A receptors in lab tests; shortened sleep onset in mice at 20 mg/kg injected. Preparation or compound: Strobile (lupulin glands)	^{5 43}
Lupulone (beta acid)	Biological association	Animal	Named among hop bitter acids with sedative activity in animal work. Preparation or compound: Strobile	^{37 43}
Isohumulones (iso-alpha acids)	Biological association	Human	Absorbed fast (peak 0.5 h) with half-life about 30 minutes after beer; used in isomerised hop extract that widened arteries in a single-dose trial. Preparation or compound: Produced when hops are boiled in brewing	^{49 59 43}
Matured hop bitter acids	Biological association	Human	Oxides derived from alpha acids, structurally like iso-alpha acids; studied at 35 mg a day for body fat, mood and cognition. Preparation or compound: Oxidised hop extract	^{40 20}
2-Methyl-3-buten-2-ol	Biological association	Pharmacological theory	Proposed by one trial's authors as a sedative principle behind hops raising GABA; this is a hypothesis in their abstract, not tested there. Preparation or compound: Formed on storage of hops	^{18 43}

Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).

Evidence at a glance: what changed in 20 lab markers

Tap a number to show only those markers. Counts are markers, not people.

Hormonal2 Metabolic2 Organ function1 Other762

The evidence

The research centre for Hops. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.

Evidence by outcome

Sleep problems: valerian-and-hops combination products (4 weeks) 5 studies · 224 people in trials Low certainty Falling asleep after a single dose of valerian-hops extract 2 studies · 74 people in trials Very low certainty Sleep after non-alcoholic beer (a drink with hops) 2 studies Very low certainty Stress, anxiety and low mood: hop dry extract in healthy young adults 5 studies · 36 people in trials Low certainty Mood and tiredness: matured hop bitter acids in beer-type drinks 2 studies · 60 people in trials Very low certainty Attention and memory: matured hop bitter acids in older adults 2 studies · 160 people in trials Low certainty Menopausal hot flashes and other menopause complaints 7 studies · 301 people in trials Low certainty Sexual function after menopause (hop vaginal gel) 1 study · 63 people in trials Not enough evidence Belly fat: matured hop extract in overweight adults 2 studies · 400 people in trials Low certainty Appetite and weight loss: bitter hop extract 4 studies · 225 people in trials Low certainty Blood fats and insulin in metabolic syndrome (hop plus acacia) 1 study · 104 people in trials Very low certainty Blood vessel widening after a hop bitter-acid extract 1 study · 23 people in trials Very low certainty Inflammation and gut: xanthohumol (a hop compound) 4 studies · 89 people in trials Not enough evidence

Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).

How we rate evidence

High certainty

Several well-run trials or reviews agree; further research is unlikely to change the picture much.

Moderate certainty

Good trials point the same way, but some doubt remains.

Low certainty

Small, short or inconsistent trials. The finding could change with better research.

Very low certainty

Very little or very weak human data. Treat as a possibility only.

Mixed findings

Trials or reviews disagree with each other.

Not enough evidence

Not enough human research to say either way.

Evidence against

Good research found no benefit, or found harm.

We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We searched PubMed, read the full EU herbal monograph on hop strobile, and checked plant names in GBIF and NCBI and compound IDs in PubChem. Only abstracts were read for nearly all studies. Some sources were not verified: the LiverTox page was blocked and is known only from a search summary, the German Commission E monograph is known only from one trial's authors, and no NCCIH, FDA, LactMed or WHO entry was read. Two dog-poisoning counts in one abstract do not match and are flagged. Certainty ratings are the compiler's own reading, not formal grades.

Study library: every study we checked 69

Design Research type Plant part Year from Search

Study	Design	People	Product, dose, length	Result
Aghamiri 2016 The effect of Hop (Humulus lupulus L.) on early menopausal symptoms and hot flashes: A randomized placebo-controlled trial. Complement Ther Clin Pract · PMID 25982391 · DOI	Controlled trial	120 Women with early menopausal symptoms	Hop tablets (extract and dose not stated in the abstract) strobile 12 weeks · vs Placebo	Greene score lower with hops at 4, 8 and 12 weeks (adjusted differences -10.0, -18.6, -23.4); hot flashes lower (adjusted differences -8.4, -17.1, -23.8). Greene -23.4 at week 12 (CI -25.1 to -21.6); hot flashes -23.8 at week 12 (CI -21.1 to -26.4) Methods, limits and funding Outcomes: Greene scale and hot flash diary Limitations: Single-centre Iranian trial; the sizes of effect are very large for an herbal product and the abstract does not name the extract or dose, so they should be read cautiously. Registration: IRCT2013010110324N7 Read: abstract
Alkharfy 2007 Effect of valerian, valerian/hops extracts, and valerenic acid on glucuronidation in vitro. Xenobiotica · PMID 17484515 · DOI	Laboratory research in-vitro	Human liver microsomes	Valerian and valerian-hops extracts and valerenic acid root plus strobile	Two herbal extracts reduced the making of acetaminophen, estradiol, morphine and testosterone glucuronides; the authors suspect valerenic acid (from valerian). Estradiol 3-glucuronidation cut by nearly 87% Methods, limits and funding Outcomes: Glucuronidation (a drug-clearing step) Limitations: Test-tube study of valerian with and without hops; the effect is not tied to hops alone. Read: abstract
Becker 2023 A retrospective evaluation of hops ingestion in 177 dogs (2005-2018). J Vet Emerg Crit Care (San Antonio) · PMID 36908194 · DOI	Observational animal	177 Dogs reported to Pet Poison Helpline 2005 to 2018	Hops swallowed (known or suspected) strobile Signs mostly 2 to 8 hours after eating	Signs in 74% (131 of 177): fast breathing, fever and vomiting. Outcome known for 83; 79 of 83 (95.2%) survived. Severe fever (above 41.4 C) in 8 dogs, 3 of whom died. 95.2% survival of known outcomes Methods, limits and funding Outcomes: Signs and survival Limitations: Outcome known for fewer than half of the cases. Read: abstract
Benkherouf 2020 Hops compounds modulatory effects and 6-prenylnaringenin dual mode of action on GABA(A) receptors. Eur J Pharmacol · PMID 32001220 · DOI	Laboratory research in-vitro	Rat brain membranes and cell assays	Hop compounds humulone and 6-prenylnaringenin strobile compounds	Humulone (an alpha acid) and 6-prenylnaringenin boosted GABA-A receptor activity at low micromolar concentrations in lab tests. IC50 about 3.2 and 3.7 micromolar Methods, limits and funding Outcomes: GABA-A receptor modulation Limitations: Laboratory only; no human relevance shown. Read: abstract
Benkherouf 2020 Humulone Modulation of GABA(A) Receptors and Its Role in Hops Sleep-Promoting Activity. Front Neurosci · PMID 33177986 · DOI	Animal research animal	Cell assays, rat brain membranes and BALB/c mice	Humulone (hop alpha acid) alone and with ethanol strobile compound 10 to 20 mg/kg by injection in mice	Humulone boosted GABA-A receptor currents, shortened pentobarbital sleep onset, lengthened sleep and cut spontaneous movement in mice. Ethanol added to the lab effect. Sedative effect in mice Methods, limits and funding Outcomes: GABA-A receptor currents; sleep onset and duration with pentobarbital or ethanol; movement Limitations: Injected doses in mice; not a measure of tea, capsules or beer in people. Read: abstract
Bitarafan 2023 Effects of intraduodenal or intragastric administration of a bitter hop extract (Humulus lupulus L.), on upper gut motility, gut hormone secretion and energy intake in healthy-weight men. Appetite · PMID 36781111 · DOI	Controlled trial	26 Healthy lean men (15 in part A, 11 in part B)	Bitter hop extract given directly into the duodenum or stomach through a tube strobile 100 or 250 mg Single dose · vs Vehicle (canola oil)	The 250 mg dose in the duodenum modestly raised pyloric pressure and PYY. No effect on appetite, symptoms or energy intake at any dose or route; the authors conclude no appetite-suppressant effect. No energy-intake effect Methods, limits and funding Outcomes: Gut pressure, CCK, PYY, appetite, energy intake Limitations: Tube delivery in a gut lab, 26 men, not capsule use; contradicts the 2022 capsule trial on the energy-intake result. Funding and conflicts: None declared. Read: abstract
Bolca 2007 Microbial and dietary factors associated with the 8-prenylnaringenin producer phenotype: a dietary intervention trial with fifty healthy post-menopausal Caucasian women. Br J Nutr · PMID 17521469 · DOI	Uncontrolled trial	50 Healthy postmenopausal women	Hop-based supplements three times a day strobile Three times a day 5 days	Urinary recovery was low and varied; women were classed as poor (60%), moderate (25%) or strong (15%) 8-PN producers by gut bacteria; recent antibiotics seemed to lower production. 60% poor, 25% moderate, 15% strong producers Methods, limits and funding Outcomes: Urinary recovery of hop flavonoids and 8-PN production from isoxanthohumol Limitations: Five-day study, no placebo. Read: abstract
Bradley 2026 Safety and Tolerability of Xanthohumol in Adults With Crohn's Disease: Results of a Triple-Masked, Randomized, Placebo-Controlled Phase 2 Trial. Mol Nutr Food Res · PMID 41834265 · DOI	Controlled trial	20 Adults with active Crohn's disease	Xanthohumol 24 mg a day strobile compound 24 mg a day 8 weeks · vs Placebo	Well tolerated; no serious adverse events attributed; minor lab changes; BMI and gamma-GT differences favoured xanthohumol (p = 0.04 and 0.02). Disease activity was not the primary outcome. BMI -0.67, GGT -4.8 U/L vs placebo Methods, limits and funding Outcomes: Safety; disease activity (CDAI) Limitations: A safety trial in 20 people; the abstract reports no disease-activity result. Funding and conflicts: Authors had earlier grant support and product from Metagenics. Read: abstract
Brunelli 2007 8-Prenylnaringenin, inhibits estrogen receptor-alpha mediated cell growth and induces apoptosis in MCF-7 breast cancer cells. J Steroid Biochem Mol Biol · PMID 17681752 · DOI	Laboratory research in-vitro	MCF-7 human breast cancer cells	8-prenylnaringenin strobile compound	8-PN activated estrogen receptor alpha signalling like estradiol but did not activate the PI3K/Akt route, and in this system it slowed cell cycle progression and caused cell death. Cell data only Methods, limits and funding Outcomes: Estrogen receptor signalling and cell growth Limitations: Cells only; says nothing about breast cancer risk in women. Read: abstract
Calvo-Castro 2018 The Oral Bioavailability of 8-Prenylnaringenin from Hops (Humulus Lupulus L.) in Healthy Women and Men is Significantly Higher than that of its Positional Isomer 6-Prenylnaringenin in a Randomized Crossover Trial. Mol Nutr Food Res · PMID 29363261 · DOI	Controlled trial	16 Healthy women and men	Pure 8-prenylnaringenin or 6-prenylnaringenin (500 mg single dose) strobile compounds 500 mg single dose Single dose · vs Placebo	8-PN reached much higher blood levels than 6-PN (Cmax 2,834 vs 543 nmol/L; AUC 15,801 vs 3,635 nmol/L x h). 8-PN about 4 to 5 times more available than 6-PN Methods, limits and funding Outcomes: Blood levels, safety Limitations: Pure compound at a high single dose, not an ordinary hop extract. Read: abstract
Carbone 2022 An Updated Review of the Genus Humulus: A Valuable Source of Bioactive Compounds for Health and Disease Prevention. Plants (Basel) · PMID 36559547 · DOI	Narrative review mixed	Genus Humulus	Hop and other Humulus species strobile	Reports strobile contents (bitter acids, polyphenols, prenylflavonoids), reports of anti-inflammatory and phytoestrogen activity, and says hop is allowed in several pharmacopoeias mainly for anxiety states. Review Methods, limits and funding Outcomes: Overview Limitations: Narrative review using bibliometric analysis. Read: abstract
Chadwick 2006 The pharmacognosy of Humulus lupulus L. (hops) with an emphasis on estrogenic properties. Phytomedicine · PMID 16360942 · DOI	Narrative review	Hop pharmacognosy and estrogenic activity	Hops strobile	Found only two trials of hops for menopausal symptoms up to 2003. Review Methods, limits and funding Outcomes: Review through 2003 Limitations: Old review (through 2003). Read: abstract
Dimpfel 2008 Sleep improving effects of a single dose administration of a valerian/hops fluid extract - a double blind, randomized, placebo-controlled sleep-EEG study in a parallel design using electrohypnograms. Eur J Med Res · PMID 18559301	Controlled trial	42 Poor sleepers identified by questionnaire	Valerian-hops fluid extract (2 ml in 50 ml water, single dose 15 min before EEG) root (valerian) plus strobile (hop) 2 ml, single One night (after a reference night) · vs Placebo	Time spent asleep was higher with the extract than placebo (p < 0.01), and time in deeper sleep differed between reference and treatment night (p < 0.01). The EEG measure correlated with the sleep-quality rating (r = 0.48). p < 0.01 for sleep quantity measures Methods, limits and funding Outcomes: Sleep EEG (electrohypnogram) and sleep questionnaire Limitations: One night only, 20 vs 22 people, a non-standard EEG method, combination product. Funding not stated in the abstract. Read: abstract
Dorn 2010 Xanthohumol feeding does not impair organ function and homoeostasis in mice. Food Chem Toxicol · PMID 20427021 · DOI	Animal research animal	Female BALB/c mice	Xanthohumol in feed strobile compound About 1000 mg/kg body weight a day 3 weeks · vs Standard diet	No signs of toxicity in organs or serum biochemistry; no liver injury markers. No toxicity at about 1000 mg/kg Methods, limits and funding Outcomes: Organ function and liver Limitations: Mice only, 3 weeks. Read: abstract
Duncan 1997 Malignant hyperthermia-like reaction secondary to ingestion of hops in five dogs. J Am Vet Med Assoc · PMID 8977648	Case series animal	5 Five dogs (four Greyhounds)	Spent hops swallowed (brewing waste) strobile Not given Onset about 3 hours	Marked fever (hyperthermia), restlessness, panting, vomiting, abdominal pain and seizures; four of five dogs died. Four of five dogs died Methods, limits and funding Outcomes: Clinical signs Limitations: Five dogs only; a Greyhound over-representation suggested a malignant-hyperthermia-like reaction. Read: abstract
EMA Committee on Herbal Medicinal Products (HMPC) 2014 Community herbal monograph on Humulus lupulus L., flos (hop strobile) EMA/HMPC/682384/2013 · Source	Authoritative guidance	Adolescents, adults, elderly; traditional use only	Hop strobile (tea, powder, liquid extracts, tincture, dry extract) strobile (cone)	Traditional herbal medicine for relief of mild symptoms of mental stress and to aid sleep, based only on long use. Contraindication: allergy to the plant. Not recommended in children under 12, in pregnancy or breastfeeding. May impair driving. Interactions: none reported. Undesirable effects: none known. No overdose reported. Genotoxicity, reproductive toxicity and cancer tests have not been done. See a doctor if symptoms last more than two weeks. Methods, limits and funding Outcomes: Indication, contraindications, warnings, interactions, pregnancy and lactation, driving, adverse effects, overdose Limitations: Traditional-use document: it does not prove that hops work. Adopted 6 May 2014 (first systematic review; the earlier version dates from 8 May 2008). EMA lists the monograph as under an ongoing call for scientific data. Read: full-text
Erkkola 2010 A randomized, double-blind, placebo-controlled, cross-over pilot study on the use of a standardized hop extract to alleviate menopausal discomforts. Phytomedicine · PMID 20167461 · DOI	Controlled trial	36 Menopausal women	Hop extract standardised to 100 micrograms 8-prenylnaringenin a day strobile 100 micrograms 8-PN a day 16 weeks crossover (8 weeks each) · vs Placebo	After 8 weeks both groups improved, placebo slightly more. The overall treatment effect was not significant; at 16 weeks time-specific differences were significant for Kupperman index (p = 0.02) and VAS (p = 0.03). Overall effect not significant; KI p = 0.02 and VAS p = 0.03 at week 16 only Methods, limits and funding Outcomes: Kupperman index, Menopause Rating Scale, visual analogue scale Limitations: Pilot, 36 women, first-period result did not favour hops, carry-over possible in a crossover, time-specific tests after a non-significant overall effect. Funding not stated in the abstract. Read: abstract
Franco 2012 The sedative effect of non-alcoholic beer in healthy female nurses. PLoS One · PMID 22815680 · DOI	Non randomised trial	17 Healthy female nurses on rotating or night shifts	Non-alcoholic beer containing hops (333 ml, 0.0% alcohol) with supper strobile (as beer) 333 ml with supper 14 days · vs The same women without beer (own control)	Sleep latency 12.0 vs 20.5 minutes (p <= 0.05); total activity during sleep lower (p <= 0.05); state anxiety 18.1 vs 20.7 (no test result given in the abstract). Sleep latency 12.01 vs 20.50 min Methods, limits and funding Outcomes: Sleep (wrist actigraphy), anxiety (STAI) Limitations: Open trial, no placebo beer, 17 women, same people compared before and after; a drink with many other ingredients (malt, polyphenols), so hops cannot be isolated. Read: abstract
Franco 2014 Effect of non-alcoholic beer on Subjective Sleep Quality in a university stressed population. Acta Physiol Hung · PMID 25183509 · DOI	Uncontrolled trial	30 University students under exam stress	Non-alcoholic beer with dinner strobile (as beer) One beer at dinner 14 days after a 7-day control week · vs Own control week	Sleep latency and global PSQI score improved (p < 0.05). p < 0.05 for latency and global score Methods, limits and funding Outcomes: Pittsburgh Sleep Quality Index Limitations: No placebo drink, no blinding, 30 students; hops cannot be separated from the rest of beer. Read: abstract
Fukuda 2020 Effects of Hop Bitter Acids, Bitter Components in Beer, on Cognition in Healthy Adults: A Randomized Controlled Trial. J Agric Food Chem · PMID 31808686 · DOI	Controlled trial	60 Healthy adults aged 45 to 64 aware of cognitive decline	Matured hop bitter acids (MHBA) strobile (oxidised hop extract) 35 mg a day 12 weeks · vs Placebo	Verbal fluency change at week 6 higher with MHBA (p = 0.034); Stroop score lower at week 12 (p = 0.019); subjective fatigue (p = 0.008) and anxiety (p = 0.043) improved at week 12. p = 0.034, 0.019, 0.008, 0.043 for the four outcomes named Methods, limits and funding Outcomes: Verbal fluency, Stroop test, subjective fatigue and anxiety Limitations: Small, 12 weeks, many outcomes tested without any correction mentioned, healthy people with self-perceived decline. The abstract gives no funding statement; the same lead author's 2022 beer study was funded by Kirin Holdings, which holds patents on these products. Read: abstract
Fukuda 2020 Supplementation with Matured Hop Bitter Acids Improves Cognitive Performance and Mood State in Healthy Older Adults with Subjective Cognitive Decline. J Alzheimers Dis · PMID 32474473 · DOI	Controlled trial	100 Adults aged 45 to 69 with subjective cognitive decline	Matured hop bitter acids (MHBA) capsules strobile (oxidised hop extract) 12 weeks · vs Placebo	Attention score higher (p = 0.045) and beta-endorphin lower (p = 0.043) with MHBA at 12 weeks; transthyretin higher (p = 0.048). Memory retrieval improved in a subgroup. SDMT p = 0.045; beta-endorphin p = 0.043; transthyretin p = 0.048 Methods, limits and funding Outcomes: Symbol Digit Modalities Test (attention), memory tests, mood, blood markers Limitations: Several outcomes tested, only some significant, a subgroup finding, p-values close to 0.05. The abstract gives no funding statement (it points to disclosures online, which we did not open). The same research group published a 2022 beer study funded by Kirin Holdings, the patent holder for matured hop bitter acid products. Funding and conflicts: Not stated in the abstract. Read: abstract
Fukuda 2022 Effect of non-alcoholic beer containing matured hop bitter acids on mood states in healthy adults: A single-arm pilot study. Nurs Health Sci · PMID 34741379 · DOI	Uncontrolled trial	97 Healthy adults aged 23 to 72	Non-alcoholic beer containing 35 mg matured hop bitter acids strobile (as beer) 35 mg MHBA in the beer 3 weeks · vs Own baseline (single-arm, open label)	Total mood, anxiety, depression, fatigue and vigor, sleep quality and presenteeism improved against baseline. Improvements vs baseline; no control group Methods, limits and funding Outcomes: Mood states, sleep quality, work performance Limitations: No control group and no blinding, so placebo and expectation effects cannot be ruled out. Study funded by Kirin Holdings, which holds patents on the MHBA products. Funding and conflicts: Funder Kirin Holdings; some authors are employees; the company holds patents on the MHBA products. Read: abstract
GBIF 2026 GBIF Backbone Taxonomy: Humulus lupulus L. GBIF API (usageKey 2984535) · Source	Database plant	Not applicable	Humulus lupulus L. strobile	Accepted species, family Cannabaceae, order Rosales, authority L., published in Species Plantarum 1753 page 1028. Synonyms include Cannabis lupulus (L.) Scop., Humulus vulgaris Gilib., Humulus volubilis Salisb. and Humulus yunnanensis Hu. Humulus japonicus is a synonym of Humulus scandens (Lour.) Merr. in GBIF. Methods, limits and funding Outcomes: Accepted name, family, synonyms, vernacular names Limitations: Queried by API on 2026-10-25. Read: full-text
German Commission E (cited by Kyrou et al.) 2017 German Commission E monograph on hops (as cited in a 2017 trial abstract) Quoted in PMID 28742505 · Source	Authoritative guidance	Adults	Hops strobile	The trial authors write that hops are approved by the German Commission E for anxiety/mood disorders and restlessness. Methods, limits and funding Outcomes: Approved use Limitations: NOT verified: we did not read the Commission E monograph, only the trial authors' one-line mention. Read: summary-only
Guo 2006 Identification of human hepatic cytochrome P450 enzymes involved in the metabolism of 8-prenylnaringenin and isoxanthohumol from hops (Humulus lupulus L.). Drug Metab Dispos · PMID 16611861 · DOI	Laboratory research in-vitro	Human liver microsomes	8-prenylnaringenin and isoxanthohumol strobile compounds	CYP2C19 and CYP2C8 break down 8-PN; CYP1A2 turns isoxanthohumol into 8-PN. The authors suggest person-to-person differences in estrogenic effect. Km 3.7 to 17.8 micromolar Methods, limits and funding Outcomes: Which enzymes break down hop prenylflavonoids Limitations: Lab only. Read: abstract
Hemachandra 2012 Hops (Humulus lupulus) inhibits oxidative estrogen metabolism and estrogen-induced malignant transformation in human mammary epithelial cells (MCF-10A). Cancer Prev Res (Phila) · PMID 21997247 · DOI	Laboratory research in-vitro	MCF-10A human breast cells	Hop extract, 8-PN, xanthohumol strobile Extract 5 micrograms/ml; 8-PN 50 nmol/L	Hops and 8-PN reduced 4-hydroxylation of estradiol and estrogen-induced malignant transformation of the cells; xanthohumol did not. Cell data only Methods, limits and funding Outcomes: Estrogen-induced malignant change in cells Limitations: Cells only. Read: abstract
Herzinger 2004 Anaphylaxis to wheat beer. Ann Allergy Asthma Immunol · PMID 15237771 · DOI	Case report	1 A 59-year-old man	Wheat beer strobile (as beer)	The cause was wheat allergy; tests to hops were negative. Single case Methods, limits and funding Outcomes: Cause of anaphylaxis to beer Limitations: One case; useful only to show that beer reactions are not always caused by hops. Read: abstract
Heyerick 2006 A first prospective, randomized, double-blind, placebo-controlled study on the use of a standardized hop extract to alleviate menopausal discomforts. Maturitas · PMID 16321485 · DOI	Controlled trial	67 Menopausal women	Hop extract standardised to 8-prenylnaringenin (8-PN) strobile 100 or 250 micrograms 8-PN a day (per the abstract) 12 weeks · vs Placebo	All groups, placebo too, improved. The 100 microgram group beat placebo at 6 weeks (p = 0.023) but not at 12 weeks (p = 0.086). Hot flush score fell more than placebo in both hop groups at 6 weeks (p < 0.01). No dose-response: the higher dose did worse than the lower. 100 microgram group vs placebo: p = 0.023 at 6 weeks, p = 0.086 at 12 weeks Methods, limits and funding Outcomes: Modified Kupperman index, patient questionnaire, hot flush score Limitations: Small (67 women), large placebo response, higher dose less active than lower dose, benefit not significant at 12 weeks overall. Funding not stated in the abstract. Read: abstract
Jamieson 2024 Gut enterotype-dependent modulation of gut microbiota and their metabolism in response to xanthohumol supplementation in healthy adults. Gut Microbes · PMID 38358253 · DOI	Controlled trial	30 Healthy adults	Xanthohumol 24 mg a day strobile compound 24 mg a day 8 weeks · vs Placebo	No significant change in overall gut-bacteria composition; some bacteria groups changed depending on each person's gut type, and bile-acid metabolites fell in some types. Gut-type dependent changes only Methods, limits and funding Outcomes: Gut bacteria composition, bile-acid metabolites Limitations: Secondary outcomes of a 30-person safety trial; no health benefit measured. Registration: NCT03735420 Read: abstract
Jung 2022 A Xanthohumol-Rich Hop Extract Diminishes Endotoxin-Induced Activation of TLR4 Signaling in Human Peripheral Blood Mononuclear Cells: A Study in Healthy Women. Int J Mol Sci · PMID 36293555 · DOI	Controlled trial	9 Healthy normal-weight women (single-blind crossover)	Xanthohumol-rich hop extract (0.125 mg xanthohumol, single dose) strobile extract 0.125 mg xanthohumol, single dose Single dose · vs Placebo	White blood cells taken after the dose released fewer inflammatory signals when challenged in the lab. Reduced ex vivo cytokine release Methods, limits and funding Outcomes: Inflammatory cytokine release from white blood cells exposed to bacterial toxin in the lab Limitations: Nine women, one dose, lab-stimulated blood cells; no clinical outcome. Registration: NCT04847193 Read: abstract
Keiler 2013 Hop extracts and hop substances in treatment of menopausal complaints. Planta Med · PMID 23512496 · DOI	Narrative review	Menopause, hop extract and 8-prenylnaringenin	Hop extract and 8-PN strobile	Human studies are few and inconclusive on hot flushes. 8-PN activates estrogen receptor alpha, is only slightly uterus-stimulating but has estrogenic effects on the breast gland in animals. Safety and efficacy data are scarce. Review Methods, limits and funding Outcomes: Overview of menopause research Limitations: Narrative review, not a pooled analysis. Read: abstract
Kim 2021 Efficacy and Safety of a Standardized Soy and Hop Extract on Menopausal Symptoms: A 12-Week, Multicenter, Randomized, Double-Blind, Placebo-Controlled Clinical Trial. J Altern Complement Med · PMID 34399063 · DOI	Controlled trial	78 Women with moderate to severe menopausal symptoms (Kupperman index above 20)	Combined soy and hop extract (190 mg in total) strobile plus soy 190 mg combined extract 12 weeks · vs Placebo	Symptom score fell by 20.6 points vs 14.8 with placebo (p < 0.05). No significant change in endometrial thickness or hormone profiles in either group. No serious adverse events. -20.61 vs -14.80 points (p < 0.05) Methods, limits and funding Outcomes: Kupperman index, bone markers, hormones, endometrial thickness, safety Limitations: Soy and hop combination, so the effect cannot be credited to hops alone. 12 weeks only. Registration: KCT0006019 Read: abstract
Koetter 2007 A randomized, double blind, placebo-controlled, prospective clinical study to demonstrate clinical efficacy of a fixed valerian hops extract combination (Ze 91019) in patients suffering from non-organic sleep disorder. Phytother Res · PMID 17486686 · DOI	Controlled trial	Adults with non-organic insomnia (ICD-10 F51.0 to F51.2) and sleep latency of 30 minutes or more at baseline	Fixed valerian-hops dry extract combination Ze 91019 (valerian 500 mg plus hop 120 mg dry extract) vs valerian extract alone root (valerian) plus strobile (hop) See substance 4 weeks · vs Placebo; valerian extract alone	The combination reduced sleep latency more than placebo; valerian extract alone did not beat placebo. Number of participants not given in the abstract Methods, limits and funding Outcomes: Sleep latency (home recorder system) Limitations: Combination product. Participant number, effect sizes and funding are not in the abstract. Read: abstract
Kyrou 2017 Effects of a hops (Humulus lupulus L.) dry extract supplement on self-reported depression, anxiety and stress levels in apparently healthy young adults: a randomized, placebo-controlled, double-blind, crossover pilot study. Hormones (Athens) · PMID 28742505 · DOI	Controlled trial	36 Healthy young adults (mean age 24.7, 31 women) with at least mild depression, anxiety and stress scores on DASS-21	Hop dry extract (Melcalin hops), two 0.2 g capsules once daily strobile Two 0.2 g capsules daily 4 weeks per period, 2-week washout, crossover · vs Placebo	Anxiety, depression and stress scores fell more with hops than with placebo (all p < 0.05): anxiety 9.2 to 5.1, depression 11.9 to 9.2, stress 19.1 to 11.6. No change in morning cortisol or body weight. Hops: anxiety 9.2 to 5.1, depression 11.9 to 9.2, stress 19.1 to 11.6 (all p < 0.05 vs placebo) Methods, limits and funding Outcomes: DASS-21 depression, anxiety and stress scores; morning cortisol; body weight Limitations: Pilot, 36 people, mostly young women, self-report scales, 4 weeks; cortisol did not move. Cited the German Commission E approval in its conclusion. Funding not stated in the abstract. Read: abstract
Langley 2021 Xanthohumol Microbiome and Signature in Healthy Adults (the XMaS Trial): Safety and Tolerability Results of a Phase I Triple-Masked, Placebo-Controlled Clinical Trial. Mol Nutr Food Res · PMID 33629812 · DOI	Controlled trial	30 Healthy volunteers	Pure xanthohumol (99.8%) strobile compound 24 mg a day 8 weeks · vs Placebo	No clinically relevant differences from placebo in lab tests, weight, vital signs or quality of life; no serious adverse events. Non-serious events: 58 in the xanthohumol group and 42 in placebo. No clinically relevant differences Methods, limits and funding Outcomes: Safety bloods, vitals, adverse events Limitations: Small phase I trial of the pure compound, not whole hops. Read: abstract
Legette 2014 Human pharmacokinetics of xanthohumol, an antihyperglycemic flavonoid from hops. Mol Nutr Food Res · PMID 24038952 · DOI	Controlled trial	48 24 men and 24 women	Pure xanthohumol single dose strobile compound 20, 60 or 180 mg Single dose, blood for 120 hours	Xanthohumol and isoxanthohumol conjugates were the main forms in blood; 8-PN and 6-PN were undetectable in most people; xanthohumol half-life about 18 to 20 hours. Half-life about 20 hours (60 mg) Methods, limits and funding Outcomes: Blood levels Limitations: Pure compound, single dose. Read: abstract
Min 2021 GABA(A) Receptor-Mediated Sleep-Promoting Effect of Saaz-Saphir Hops Mixture Containing Xanthohumol and Humulone. Molecules · PMID 34885687 · DOI	Animal research animal	Mice and rats	Saaz-Saphir hop mixture, xanthohumol and humulone strobile 3 weeks oral in animals	The hop mixture increased sleep time and brain GABA and receptor levels in animals; GABA antagonists reduced the effect. Animal sleep time up Methods, limits and funding Outcomes: Sleep time in a caffeine insomnia model, brain GABA and GABA-A receptor expression Limitations: Animal study only. Funding and conflicts: Funders had no role in design, analysis or publication (stated). Read: abstract
Minich 2010 Hop and Acacia Phytochemicals Decreased Lipotoxicity in 3T3-L1 Adipocytes, db/db Mice, and Individuals with Metabolic Syndrome. J Nutr Metab · PMID 20721358 · DOI	Controlled trial	104 Adults with metabolic syndrome	Tablets with rho-iso-alpha acids (hop, 100 mg) plus Acacia nilotica proanthocyanidins (500 mg) strobile extract plus acacia 3 or 6 tablets a day 12 weeks · vs Placebo	The 3-tablet group had larger falls than placebo in triglycerides, TG:HDL ratio, fasting insulin and HOMA score. Greater reductions vs placebo (numbers not in the abstract) Methods, limits and funding Outcomes: Triglycerides, TG:HDL, fasting insulin, HOMA Limitations: Combination of hop and acacia extracts; the abstract gives no numbers and no funding statement. The abstract mentions the benefit for the 3-tablet group only. Read: abstract
Monteiro 2006 Effect of hop (Humulus lupulus L.) flavonoids on aromatase (estrogen synthase) activity. J Agric Food Chem · PMID 16608212 · DOI	Laboratory research in-vitro	Human placental-derived (JAR) cells	Xanthohumol, isoxanthohumol, 8-PN and beers strobile compounds	The compounds and several beers reduced aromatase activity in cell tests. IC50 values given in full paper Methods, limits and funding Outcomes: Aromatase (estrogen-making enzyme) activity Limitations: Cells only. Read: abstract
Morimoto-Kobayashi 2016 Matured hop extract reduces body fat in healthy overweight humans: a randomized, double-blind, placebo-controlled parallel group study. Nutr J · PMID 26960416 · DOI	Controlled trial	200 Healthy adults aged 20 to 64 with BMI 25 to under 30	Beverage containing matured hop extract (35 mg matured hop bitter acids), 350 ml a day strobile (oxidised hop extract) 35 mg MHBA in 350 ml 12 weeks · vs Placebo beverage	Visceral fat area fell more with the extract than with placebo at 8 and 12 weeks, and total fat area at 12 weeks; body fat ratio also fell more. No related adverse events. Significant visceral fat reduction at 8 and 12 weeks (numbers not in the abstract) Methods, limits and funding Outcomes: Abdominal fat area by CT scan Limitations: Japan only, 12 weeks, Kirin-sponsored line of research (declared in the follow-up analysis), exact fat-area numbers not in the abstract. Funding and conflicts: Sponsor Kirin Co.; follow-up paper lists employees as authors. Registration: UMIN000014185 Read: abstract
Morin 2005 Valerian-hops combination and diphenhydramine for treating insomnia: a randomized placebo-controlled clinical trial. Sleep · PMID 16335333 · DOI	Controlled trial	184 Adults (mean age 44.3) with mild insomnia, 9 US sleep centres	Valerian plus hop standardised extract combination tablets (valerian 187 mg native extract, hop 41.9 mg native extract per the abstract) root (valerian) plus strobile (hop) Two tablets nightly 28 days · vs Placebo; diphenhydramine 25 mg x2 for 14 days then placebo	Modest subjective sleep improvements with both the valerian-hops combination and diphenhydramine, but few comparisons with placebo reached statistical significance. No group differences on any polysomnography sleep-continuity measure. Physical quality of life improved more with valerian-hops than placebo at 28 days. No serious adverse events, no rebound insomnia. Reviewers call it a modest hypnotic effect; most comparisons with placebo were not significant Methods, limits and funding Outcomes: Sleep diaries, polysomnography, clinician and patient ratings, quality of life, safety Limitations: Combination product (cannot credit hops alone). The abstract gives no funding statement. Read: abstract
NCBI 2017 NCBI Taxonomy: Humulus lupulus (European hop) NCBI Taxonomy, taxid 3486 · Source	Database plant	Not applicable	Humulus lupulus unspecified	Species rank, common name European hop, taxid 3486 (record modified 2017). Methods, limits and funding Outcomes: Accepted species record Limitations: Queried by API (esummary) on 2026-10-25. Read: full-text
NCBI PubChem 2026 PubChem compound records for hop constituents PubChem PUG REST · Source	Database compound	Not applicable	Hop compounds strobile	CIDs confirmed by name search on 2026-10-25: xanthohumol 639665; 8-prenylnaringenin 480764; 6-prenylnaringenin 155094; isoxanthohumol 513197; humulone 442911; lupulone 68051; isohumulone 93090; 2-methyl-3-buten-2-ol 8257. Methods, limits and funding Outcomes: Compound identifiers and formulas Limitations: Name lookup returns the first matching record; stereoisomer records may differ. Read: full-text
NIDDK LiverTox (NCBI Bookshelf) 2018 LiverTox: Hops (Humulus lupulus) NBK548872 · Source	Authoritative guidance	General	Hops (Humulus lupulus) unspecified	Per a web-search summary of the entry (the page itself was blocked by a verification screen and could not be opened): rated likelihood score E (unlikely cause of clinically apparent liver injury); hops not implicated in enzyme rises or clinically apparent liver injury; last updated 2018. Methods, limits and funding Outcomes: Likelihood of causing liver injury Limitations: NOT verified from the page itself. Only a search-engine summary was seen. Read: summary-only
Nikolic 2004 Metabolism of 8-prenylnaringenin, a potent phytoestrogen from hops (Humulus lupulus), by human liver microsomes. Drug Metab Dispos · PMID 14744951 · DOI	Laboratory research in-vitro	Human liver microsomes	8-prenylnaringenin strobile compound	Twelve metabolites were found, mostly from oxidation of the prenyl group. 12 metabolites Methods, limits and funding Outcomes: Metabolism Limitations: Lab only. Read: abstract
Pfaff 2022 Retrospective analysis of hops toxicosis in dogs (2002-2014): 71 cases. J Vet Emerg Crit Care (San Antonio) · PMID 34498796 · DOI	Observational animal	71 Dogs with known hop ingestion, ASPCA poison control and Tufts records 2002 to 2014	Hops swallowed strobile Median 2 vs 2.5 oz between survivors and non-survivors Death at a median of 10.7 hours in non-survivors	Fever (hyperthermia) in 96% of dogs; 77% survived with intensive treatment per the abstract; each degree of body-temperature rise was linked to 78% higher odds of death; survivors recovered fully. 96% hyperthermia; 77% survival (stated) Methods, limits and funding Outcomes: Signs, treatment, survival Limitations: Retrospective poison-control cases. The abstract states 59 survivors of 71 (which would be 83%) and 77% survival; we quote the abstract's wording and note the mismatch. Read: abstract
Piasecka-Kwiatkowska 2024 Allergenic Potential of Common Hops (Humulus lupulus L.) in the Context of Cross-Reactions with Pollen Allergens. Nutrients · PMID 39519459 · DOI	Laboratory research in-vitro	Hop stalk, leaf and cone proteins tested with antibodies and sera of three pollen-allergic patients	Hop protein extracts of three cultivars stalk, leaf, strobile	Native hop proteins showed cross-reactivity with the main pollen allergens in lab tests. Cross-reactivity seen Methods, limits and funding Outcomes: Immune cross-reactivity with birch, mugwort and grass pollen allergens Limitations: Preliminary lab study with three patient samples. Read: abstract
Pradalier 2002 [Systemic urticaria induced by hops]. Allerg Immunol (Paris) · PMID 12512192	Case report	1 One patient	Wild hop unspecified	Repeated whole-body hives with joint pain and fever were traced to wild hop and treated with corticosteroids. Single case Methods, limits and funding Outcomes: Systemic hives with joint pain and fever Limitations: One case, from a French-language paper whose abstract is in English. Read: abstract
Rodda 2014 Pharmacokinetics of iso-α-acids in volunteers following the consumption of beer. J Anal Toxicol · PMID 24778090 · DOI	Uncontrolled trial	5 Five volunteers	Beer with higher or lower iso-alpha-acids strobile (as beer) Small volumes 6 hours	Iso-alpha acids were absorbed quickly (peak at 0.5 h) and the estimated half-life was about 30 minutes. Half-life about 30 minutes Methods, limits and funding Outcomes: Blood levels of iso-alpha acids Limitations: Five people; a forensic-method paper. Read: abstract
Salter 2010 Treating primary insomnia - the efficacy of valerian and hops. Aust Fam Physician · PMID 20628685	Systematic review	Adults with primary insomnia	Valerian alone or with hops root plus strobile Various Various · vs Various	Sixteen studies met the criteria; twelve found valerian alone or with hops linked to some improvement in sleep measures. Authors say the results need caution because the studies differed widely, and more good trials are needed. 12 of 16 studies reported some improvement Methods, limits and funding Outcomes: Efficacy in primary insomnia Limitations: A review of mostly valerian studies, covers literature to 2009. Not a pooled analysis. Read: abstract
Savage 2018 GABA-modulating phytomedicines for anxiety: A systematic review of preclinical and clinical evidence. Phytother Res · PMID 29168225 · DOI	Systematic review	Preclinical and clinical studies of GABA-acting plants for anxiety	Ten plants including hops various Various Various · vs Various	Ten plants, hops among them, had both GABA-related preclinical findings and human trials. The review reports comparative anxiolytic effect to current medicines with good safety, but the abstract gives no hops-specific figures. No hops-specific numbers in the abstract Methods, limits and funding Outcomes: Preclinical and clinical evidence Limitations: Overall statement for ten plants, not hops alone; the abstract gives no certainty rating. Read: abstract
Schellenberg 2004 The fixed combination of valerian and hops (Ze91019) acts via a central adenosine mechanism. Planta Med · PMID 15254851 · DOI	Controlled trial	32 Healthy volunteers (16 per group) given caffeine 200 mg	Fixed valerian-hop extract combination Ze 91019 (2 or 6 tablets) root plus strobile 2 or 6 tablets Single dose · vs Placebo	The extract reduced (2 tablets) or blocked (6 tablets) the caffeine arousal at 60 minutes, which the authors read as an adenosine-related effect. Reduced or blocked caffeine arousal Methods, limits and funding Outcomes: EEG arousal after caffeine Limitations: A brain-wave test in healthy volunteers, not a sleep or insomnia outcome; the group count is from the abstract (16 per group). Read: abstract
Schicktanz 2025 Effects of a Valerian-Hops Extract Combination (Ze 91019) on Sleep Duration and Daytime Cognitive and Psychological Parameters in Occasional Insomnia: A Randomized Controlled Feasibility Trial. Brain Behav · PMID 40462685 · DOI	Controlled trial	40 Adults with occasional sleep problems	Valerian-hops extract combination Ze 91019 root (valerian) plus strobile (hop) 21 days of treatment after a 21-day run-in · vs Placebo	Feasible. Exploratory analysis: sleep duration up by 21.7 minutes a day (p = 0.019) and by 48.7 minutes on the shortest night; no significant effects on cognitive or psychological measures; well tolerated. +21.7 min/day sleep duration (exploratory, p = 0.019) Methods, limits and funding Outcomes: Feasibility, wearable-tracked sleep duration, daily online cognitive tests, mood and stress surveys Limitations: Feasibility trial, 40 people, exploratory analysis, Fitbit-type tracker rather than lab sleep recording. Combination product. Registration: NCT05684523 Read: abstract
Spiess 2022 Medicinal Plants for the Treatment of Mental Diseases in Pregnancy: An In Vitro Safety Assessment. Planta Med · PMID 34624906 · DOI	Laboratory research in-vitro	BeWo b30 placental cell model	Hop extract and other mood herbs strobile Up to 30 micrograms/ml	No harmful effects up to 30 micrograms/ml for hops among the herbs tested; minimal cytotoxicity at 100 micrograms/ml. The authors say studies in pregnant women are needed. No harm at tested concentrations Methods, limits and funding Outcomes: Cell toxicity, DNA damage, metabolism Limitations: Placental cell line only; not a pregnancy study. Read: abstract
Spiewak 2002 Occupational airborne and hand dermatitis to hop (Humulus lupulus) with non-occupational relapses. Ann Agric Environ Med · PMID 12498595	Case report	1 A 57-year-old hop farmer	Fresh and dried hop leaves and cones; beauty cream and herbal sedative containing hop extract leaf and strobile	Airborne and hand dermatitis with eyelid swelling and conjunctivitis; prick tests were positive to leaf and cone extracts and a cone patch test was positive; the herbal sedative and a beauty cream containing hop extract were found as new sources of allergen. Single case Methods, limits and funding Outcomes: Skin tests and relapses Limitations: One case; occupational exposure. Read: abstract
Suzuki 2018 The relationship between the effect of matured hop extract and physical activity on reducing body fat: re-analysis of data from a randomized, double-blind, placebo-controlled parallel group study. Nutr J · PMID 30376838 · DOI	Controlled trial	200 Overweight Japanese adults (re-analysis)	Matured hop extract strobile (oxidised hop extract) Same as parent trial 12 weeks · vs Placebo	Visceral fat change correlated with steps in the active group (r = -0.208, p = 0.048); the interaction with walking was borderline (p = 0.055). r = -0.208, p = 0.048 Methods, limits and funding Outcomes: Link between daily steps and fat change Limitations: Post-hoc re-analysis of the same trial, borderline results. Authors are employees of the sponsor Kirin. Funding and conflicts: Authors are employees of Kirin Co., Ltd., the study sponsor. Registration: UMIN000014185 Read: abstract
Tanaka 2022 8-Prenylnaringenin tissue distribution and pharmacokinetics in mice and its binding to human serum albumin and cellular uptake in human embryonic kidney cells. Food Sci Nutr · PMID 35432956 · DOI	Animal research animal	C57/BL6 mice; human serum albumin and kidney cells	8-prenylnaringenin strobile compound 50 mg/kg 22 days feeding	8-PN reached kidneys, liver, muscle, lungs, pancreas, heart, spleen and brain in mice, in higher amounts than the non-prenylated naringenin. Kidney 16.8 nmol/g, liver 14.8, brain 0.31 Methods, limits and funding Outcomes: Tissue distribution and blood levels Limitations: Mice only. Funding and conflicts: Partly funded by Dicel Corporation; two authors are Dicel employees. Read: abstract
Tjeerdsma 2023 Analysis of Safety Concerns on Herbal Products with Assumed Phytoestrogenic Activity. Pharmaceuticals (Basel) · PMID 37631050 · DOI	Observational	Adverse-reaction reports (Netherlands Lareb and WHO VigiBase) and a scoping review of phytoestrogen products	Products with assumed phytoestrogen activity including hops various	In the Dutch Lareb database, 67 reports involved such products, and hops were named in 32.8% of them (second after black cohosh at 47.8%). Reactions were most often stomach and gut, skin, reproductive system and breast disorders. The review linked phytoestrogen products with postmenopausal bleeding. Hops: 32.8% of 67 Dutch reports Methods, limits and funding Outcomes: Reported adverse reactions Limitations: Spontaneous reports: they cannot give rates or prove cause. Many reports involved mixed products. Read: abstract
Tomita 2017 Acute improvement of endothelial functions after oral ingestion of isohumulones, bitter components of beer. Biochem Biophys Res Commun · PMID 28131837 · DOI	Controlled trial	23 12 smokers and 11 non-smokers	Isomerised hop extract (isohumulones, hop bitter acids) single oral dose strobile (processed extract) Single oral dose (amount not in the abstract) Single dose, crossover · vs Placebo	Artery widening rose 30 and 120 minutes after the extract in both smokers and non-smokers; the extract also protected cultured cells. FMD rose at 30 and 120 min (p-values not given in the abstract) Methods, limits and funding Outcomes: Flow-mediated vasodilatation (artery widening) Limitations: Acute test in 23 people; a short-lived blood-vessel measure, not heart disease. Read: abstract
Trius-Soler 2021 Moderate Consumption of Beer (with and without Ethanol) and Menopausal Symptoms: Results from a Parallel Clinical Trial in Postmenopausal Women. Nutrients · PMID 34209273 · DOI	Non randomised trial	37 Postmenopausal women	Beer with alcohol (330 ml a day), non-alcoholic beer (660 ml a day) or no beer strobile (as beer) See substance 6 months · vs Control group without beer	Both beers lowered symptom severity vs control (p = 0.009 and 0.033). Sex hormone profile did not differ. p = 0.009 (alcoholic beer), p = 0.033 (non-alcoholic) Methods, limits and funding Outcomes: Menopausal symptom severity, hormones, lipids, blood pressure Limitations: Small (34 finishers, 7 in one arm); the abstract does not say people were randomly assigned; beer, not hop extract. Funded partly by alcohol and brewing groups. Funding and conflicts: Authors report funding or fees from alcohol-research and brewing-industry bodies. Read: abstract
Vahedpoorfard 2023 Effect of Humulus lupulus L. (Hop) on Postmenopausal Sexual Dysfunction: A Randomized Clinical Trial. Int J Clin Pract · PMID 37101856 · DOI	Controlled trial	63 Postmenopausal women with sexual dysfunction	Vaginal gel containing hop extract strobile Daily for 7 days, then twice weekly 2 months · vs Vaginal estradiol 0.625 mg (no placebo)	No significant difference in FSFI scores between the hop gel and estradiol groups; the authors say the gel was as effective as estradiol, with no adverse events. No difference in FSFI vs estradiol (p > 0.05) Methods, limits and funding Outcomes: Female Sexual Function Index (FSFI) Limitations: No placebo group, so improvement cannot be credited to hops. "No difference" from estradiol does not prove equivalence. Applied to the vagina, so not a swallowed product. Registration: IRCT20210405050859N1 Read: abstract
Walker 2019 New Zealand Bitter Hops Extract Reduces Hunger During a 24 h Water Only Fast. Nutrients · PMID 31766216 · DOI	Controlled trial	30 Adult men doing a 24-hour water-only fast	Bitter hops-based appetite suppressant (Amarasate), 100 or 250 mg twice daily at 16 and 20 hours strobile 100 or 250 mg at 16 h and 20 h 24-hour fast, 3 weekly sessions · vs Placebo	Hunger fell by more than 10% from 18 to 24 hours with both doses (p < 0.05); the lunchtime hunger rise seen with placebo was absent. >10% hunger reduction (p < 0.05) Methods, limits and funding Outcomes: Hunger ratings Limitations: Subjective hunger in 30 men over a single fast each; research institute holds a licence with the supplement maker. Funding and conflicts: The research institute has a licensing agreement with Calocurb Ltd; internal funding. Read: abstract
Walker 2022 An extract of hops (Humulus lupulus L.) modulates gut peptide hormone secretion and reduces energy intake in healthy-weight men: a randomized, crossover clinical trial. Am J Clin Nutr · PMID 35102364 · DOI	Controlled trial	19 Healthy-weight men	Bitter hop extract capsules (500 mg), gastric or duodenal release strobile 500 mg single dose Single day per treatment, 1-week washout · vs Placebo	Total energy intake fell with both hop treatments (about 4,470 kJ vs 5,383 kJ placebo, p = 0.006 and 0.004). Ghrelin, CCK, GLP-1 and PYY rose; insulin fell without a change in blood sugar. Gut discomfort (nausea, bloating) rose, with mild to severe stomach and gut symptoms in the quick-release group. Self-rated appetite did not change. Energy intake 4,473 kJ and 4,439 kJ vs 5,383 kJ placebo Methods, limits and funding Outcomes: Energy intake at lunch and snack, gut hormones, appetite, discomfort Limitations: Single-day test in 19 lean men. The abstract gives no funding statement; the same lead author's 2019 trial of a hop supplement declares a licence between the authors' institute and Calocurb Ltd. Read: abstract
Walker 2026 Bitter hop nutraceutical stimulates fat mass loss while preserving muscle mass in a cohort of individuals with overweight or obesity receiving diet and exercise advice. Obes Pillars · PMID 42494803 · DOI	Controlled trial	150 Adults with overweight or obesity on a 24-week weight-loss programme (128 completed)	Bitter hop extract 500 mg a day strobile 500 mg a day, split before meals 24 weeks · vs Placebo	Weight fell 3.8% more and fat mass 3.9 kg more than with placebo (p < 0.05); no loss of muscle mass by bioimpedance. Weight -3.8%, fat mass -3.9 kg vs placebo Methods, limits and funding Outcomes: Weight, fat mass (bioimpedance), appetite Limitations: Bioimpedance, not a scan, 128 completers of 150; the research institute holds a licence with the supplement maker and a minor shareholding. Funding and conflicts: Institute has licensed the extract to Calocurb Ltd and holds a minor shareholding. Registration: ACTRN12625001011471 Read: abstract
Wang 2016 Hop (Humulus lupulus L.) Extract and 6-Prenylnaringenin Induce P450 1A1 Catalyzed Estrogen 2-Hydroxylation. Chem Res Toxicol · PMID 27269377 · DOI	Laboratory research in-vitro	Human breast cell lines (MCF-10A, MCF-7)	Hop extract and hop compounds strobile	Hop extract and 6-prenylnaringenin favoured the non-toxic estrogen 2-hydroxylation route via CYP1A1. Cell data only Methods, limits and funding Outcomes: Estrogen metabolism and P450 1A1 induction Limitations: Lab study in cells. Read: abstract
Wesołowska 2010 8-Prenylnaringenin is an inhibitor of multidrug resistance-associated transporters, P-glycoprotein and MRP1. Eur J Pharmacol · PMID 20633549 · DOI	Laboratory research in-vitro	Human cells and red blood cells	8-prenylnaringenin strobile compound	8-PN inhibited the drug pumps MRP1 and P-glycoprotein in cell tests. IC50 5.76 micromolar for MRP1 Methods, limits and funding Outcomes: Drug-transporter inhibition Limitations: Lab only. Read: abstract
Yuan 2014 Inhibition of human cytochrome P450 enzymes by hops (Humulus lupulus) and hop prenylphenols. Eur J Pharm Sci · PMID 24342125 · DOI	Laboratory research in-vitro	Human enzyme assays	Standardised hop extract and hop prenylphenols strobile Extract at 5 micrograms/ml	The extract blocked CYP2C8 (93%), CYP2C9 (88%), CYP2C19 (70%) and CYP1A2 (27%); 8-prenylnaringenin and isoxanthohumol were the most potent. The authors say this may affect drugs cleared by the CYP2C family. IC50 0.8 (2C8), 0.9 (2C9), 3.3 (2C19), 9.4 (1A2) micrograms/ml Methods, limits and funding Outcomes: Inhibition of drug-metabolising CYP enzymes Limitations: Test-tube study; no human interaction study has confirmed this. Read: abstract
Zanoli 2008 Pharmacognostic and pharmacological profile of Humulus lupulus L. J Ethnopharmacol · PMID 18308492 · DOI	Narrative review mixed	Hop pharmacognosy and pharmacology	Hops strobile	Reviews sleep traditions, laboratory work on sedative principles and the limits of the evidence. Review Methods, limits and funding Outcomes: Overview Limitations: Narrative review; results variable. Read: abstract
Štulíková 2018 Therapeutic Perspectives of 8-Prenylnaringenin, a Potent Phytoestrogen from Hops. Molecules · PMID 29543713 · DOI	Narrative review	8-prenylnaringenin	8-prenylnaringenin from hops strobile compound	Calls 8-PN a potent phytoestrogen; notes possible adverse effects with long-term use of phytoestrogens, and a need for safety data. Review Methods, limits and funding Outcomes: Overview of therapeutic perspectives Limitations: Narrative review. Read: abstract

What we do not know yet

What the evidence supports: nothing about hops is above low certainty. Sleep (as valerian-hops), stress and anxiety, menopause symptoms, belly fat and attention in older adults are low; the rest is very low or insufficient.
No trial tested hop extract or tea alone for insomnia, and none compared hops with valerian or with standard insomnia care.
The stress and anxiety result is one 36-person pilot, and the memory and belly-fat results come from one brewer-linked research group without independent replication.
Menopause trials are small, use different extracts, and one very large effect came from a single centre whose abstract does not name the extract or dose.
No long-term human data exist on hop plant estrogens and breast or womb tissue.
No human study of drug interactions was found; enzyme findings are from test tubes.
The German Commission E, FDA, NCCIH, LactMed and WHO entries were not read, and the LiverTox page was seen only through a search summary.
Only abstracts were read for every study; the EU monograph was read in full. For amounts, ask a doctor or pharmacist.

How new research is added

New studies are found by a saved PubMed search and are placed in a review queue. A person reads each one before it changes any evidence rating or safety wording. New publications never change ratings automatically.

Lab markers

What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".

Hormonal 2

●

Morning cortisol (blood)

No clear change in trials

A stress hormone measured in blood.

Low certainty

Results and what it means

Why it was measured

Tested to see whether hops change the body's stress response.

Statistical vs. clinical meaning

A single morning measure; shows the symptom score change was not matched by a cortisol change.

Safety implication

None noted.

Study	Result	People	Product
³⁴	No significant change with hops or placebo, even though self-reported stress scores fell	Healthy young adults, n = 36	Hop dry extract, 4 weeks

³⁴

●

Hormone profile and womb lining thickness

No clear change in trials

Blood levels of sex hormones and the ultrasound thickness of the womb lining (endometrium).

Low certainty

Results and what it means

Why it was measured

Checked in menopause trials to see if an estrogen-like herb changes the body's own hormones or the womb lining.

Statistical vs. clinical meaning

No change in 12 weeks to 6 months, which does not rule out changes over years.

Safety implication

Reassuring for the short term only; long-term effects on breast and womb are not studied.

Study	Result	People	Product
³²	Endometrial thickness and hormone profiles did not change significantly in either group	Menopausal women, n = 78	Soy plus hop extract, 12 weeks
⁶⁰	Sex hormone profile did not differ between beer and control groups	Postmenopausal women, n = 34 finishers	Beer with or without alcohol, 6 months

^{32 60}

Metabolic 2

▼

Triglycerides and TG:HDL ratio

Lowered in trials

Blood fats; a higher triglyceride to HDL ratio goes with insulin resistance.

Very low certainty

Results and what it means

Why it was measured

Part of the metabolic syndrome picture.

Statistical vs. clinical meaning

Combination product; no numbers in the abstract.

Safety implication

None noted.

Study	Result	People	Product
³⁸	Larger falls than placebo in the 3-tablet group (numbers not in the abstract)	Adults with metabolic syndrome, n = 104	Hop rho-iso-alpha acids plus acacia proanthocyanidins, 12 weeks

³⁸

▼

Fasting insulin and HOMA score

Lowered in trials

Fasting insulin and a calculated score of insulin resistance (HOMA).

Very low certainty

Results and what it means

Why it was measured

Insulin resistance underlies metabolic syndrome.

Statistical vs. clinical meaning

Combination product; abstract gives no numbers.

Safety implication

Not tested with diabetes medicines.

Study	Result	People	Product
³⁸	Greater reductions in fasting insulin and HOMA than placebo in the 3-tablet group	Adults with metabolic syndrome, n = 104	Hop plus acacia tablets, 12 weeks

³⁸

Organ function 1

▼

Gamma-glutamyltransferase (GGT) and BMI

Lowered in trials

GGT is a liver-related blood enzyme; BMI is weight relative to height.

Very low certainty

Results and what it means

Why it was measured

Safety labs in the Crohn's trial.

Statistical vs. clinical meaning

Secondary safety labs in 20 people; the authors say these may reflect a beneficial effect but did not test it.

Safety implication

No harmful liver changes were reported (laboratory elevations minor and transient).

Study	Result	People	Product
⁸	GGT -4.8 U/L (95% CI 0.8 to 8.8, p = 0.02) and BMI -0.67 (p = 0.04) vs placebo	Adults with active Crohn's disease, n = 20	Xanthohumol 24 mg a day, 8 weeks

⁸

Other 15

▼

Time to fall asleep (sleep latency)

Lowered in trials

Minutes taken to fall asleep after getting into bed.

Low certainty

Results and what it means

Why it was measured

The most common sleep outcome in insomnia trials.

Statistical vs. clinical meaning

Statistically significant in the extract trial and two uncontrolled beer studies; the large Morin trial found no polysomnography difference.

Safety implication

None noted.

Study	Result	People	Product
³³	Sleep latency fell more with valerian-hops extract than with placebo (valerian alone did not beat placebo).	Adults with non-organic insomnia	Valerian plus hops extract Ze 91019
¹⁸	12.01 vs 20.50 minutes (p <= 0.05)	Female nurses on shifts, n = 17	Non-alcoholic beer, 14 days (no placebo)
¹⁹	Sleep latency improved (p < 0.05), no numbers in the abstract	University students, n = 30	Non-alcoholic beer, 14 days (no placebo)

^{33 18 19 41}

▲

Sleep duration (wearable-tracked)

Raised in trials

Hours or minutes asleep per night as estimated by a wearable tracker.

Very low certainty

Results and what it means

Why it was measured

Used in a recent feasibility trial of the valerian-hops combination.

Statistical vs. clinical meaning

Exploratory result in a feasibility trial; wearable trackers estimate sleep only roughly.

Safety implication

None noted.

Study	Result	People	Product
⁵³	+21.7 minutes a day vs placebo (p = 0.019); +48.7 minutes on the shortest night; exploratory	Adults with occasional sleep problems, n = 40	Valerian-hops Ze 91019, 21 days

⁵³

▲

Sleep amount on EEG (electrohypnogram)

Raised in trials

A brain-wave based score of time spent asleep and in deeper sleep.

Very low certainty

Results and what it means

Why it was measured

Used to test a single dose.

Statistical vs. clinical meaning

One night, small groups, an uncommon scoring method.

Safety implication

None noted.

Study	Result	People	Product
¹³	Time asleep and time in deeper sleep higher with valerian-hops than placebo (p < 0.01)	Poor sleepers, 20 vs 22	Valerian-hops liquid extract, single dose

¹³

▼

Depression, anxiety and stress scores (DASS-21)

Lowered in trials

A 21-item self-rated questionnaire of how bad each of three feelings has been over the past week.

Low certainty

Results and what it means

Why it was measured

The main outcome of the hop extract pilot.

Statistical vs. clinical meaning

Self-reported; placebo group also improved; one small trial.

Safety implication

None noted.

Study	Result	People	Product
³⁴	Anxiety 9.2 to 5.1, depression 11.9 to 9.2, stress 19.1 to 11.6; all better than placebo (p < 0.05)	Healthy young adults with mild symptoms, n = 36	Hop dry extract, 4 weeks (crossover)

³⁴

▲

Symbol Digit Modalities Test (attention score)

Raised in trials

A paper test where you match symbols to digits quickly; a higher score means better attention and speed.

Low certainty

Results and what it means

Why it was measured

A simple measure of attention and processing speed.

Statistical vs. clinical meaning

A borderline p-value among many tests; effect size not stated in the abstract.

Safety implication

None noted.

Study	Result	People	Product
²¹	Higher at week 12 with matured hop bitter acids than placebo (p = 0.045)	Adults 45 to 69 with subjective cognitive decline, n = 100	Matured hop bitter acids, 12 weeks

²¹

▼

Beta-endorphin (blood)

Lowered in trials

A natural pain-and-stress-relieving chemical made by the body.

Very low certainty

Results and what it means

Why it was measured

Measured as a possible marker of mood and stress.

Statistical vs. clinical meaning

A lab marker; what it means for daily life is unclear.

Safety implication

None noted.

Study	Result	People	Product
²¹	Lower at week 12 with matured hop bitter acids than placebo (p = 0.043)	Adults 45 to 69 with subjective cognitive decline, n = 100	Matured hop bitter acids, 12 weeks

²¹

▲

Transthyretin (serum protein)

Raised in trials

A blood protein that carries thyroid hormone; the authors call lower levels a possible marker of mild cognitive impairment.

Very low certainty

Results and what it means

Why it was measured

Used as a possible early marker of thinking decline.

Statistical vs. clinical meaning

A putative marker, borderline p-value; no proof the change means better thinking.

Safety implication

None noted.

Study	Result	People	Product
²¹	Higher at week 12 with matured hop bitter acids than placebo (p = 0.048)	Adults 45 to 69 with subjective cognitive decline, n = 100	Matured hop bitter acids, 12 weeks

²¹

↕

Stroop test and verbal fluency

Mixed results in trials

Timed word tests: the Stroop test measures how well you ignore distraction; verbal fluency counts words you can list in a set time.

Low certainty

Results and what it means

Why it was measured

Common measures of attention and word recall.

Statistical vs. clinical meaning

Two of several cognitive tests were significant at different weeks.

Safety implication

None noted.

Study	Result	People	Product
²⁰	Verbal fluency change at week 6 higher (p = 0.034) and Stroop score lower at week 12 (p = 0.019) with matured hop bitter acids vs placebo	Healthy adults 45 to 64, n = 60	Matured hop bitter acids 35 mg a day, 12 weeks

²⁰

▼

Kupperman Menopausal Index

Lowered in trials

A score of common menopause complaints (hot flushes, sweating, sleep, mood, joint pain and others) rated by the woman; higher means more or worse symptoms.

Low certainty

Results and what it means

Why it was measured

The standard symptom score for menopause herbs.

Statistical vs. clinical meaning

Mixed; large placebo response; one combination product.

Safety implication

See safety for hormone-sensitive conditions.

Study	Result	People	Product
²⁸	Hop at 100 micrograms 8-PN beat placebo at 6 weeks (p = 0.023), not at 12 weeks (p = 0.086); everyone including placebo improved	Menopausal women, n = 67	Hop extract standardised on 8-PN
¹⁷	Overall effect not significant; difference at 16 weeks (p = 0.02)	Menopausal women, n = 36	Hop extract, 100 micrograms 8-PN, crossover
³²	-20.61 vs -14.80 points (p < 0.05)	Women with moderate to severe symptoms, n = 78	Soy plus hop extract 12 weeks

^{28 17 32}

▼

Hot flash frequency

Lowered in trials

How many hot flashes a woman records per week or day.

Low certainty

Results and what it means

Why it was measured

The main complaint for which hops are tried.

Statistical vs. clinical meaning

Effects in one trial are unusually large; the extract and dose are not given in its abstract.

Safety implication

See safety.

Study	Result	People	Product
¹	Fewer hot flashes than placebo at weeks 4, 8 and 12 (adjusted differences -8.4, -17.1, -23.8)	Women with early menopausal symptoms, n = 120	Hop tablets, 12 weeks
²⁸	Hot-flush score fell more than placebo in both hop groups at 6 weeks (p < 0.01)	Menopausal women, n = 67	Hop extract standardised on 8-PN

^{1 28}

▼

Visceral fat area (CT scan)

Lowered in trials

The area of fat around the abdominal organs, measured by CT scan.

Low certainty

Results and what it means

Why it was measured

Belly fat is linked to metabolic disease.

Statistical vs. clinical meaning

One sponsor-linked trial; CT area change is real but its effect on health is not shown.

Safety implication

No related adverse events.

Study	Result	People	Product
⁴⁰	Lower than placebo at 8 and 12 weeks (numbers not in the abstract)	Overweight Japanese adults, n = 200	Matured hop extract 35 mg bitter acids a day, 12 weeks

^{40 56}

↕

Energy eaten at the next meals

Mixed results in trials

Kilojoules eaten at a free-choice lunch and snack after taking a capsule.

Very low certainty

Results and what it means

Why it was measured

A direct test of whether bitter hop extract reduces food intake.

Statistical vs. clinical meaning

The two trials disagree.

Safety implication

Gut discomfort in the first trial.

Study	Result	People	Product
⁶³	Lower by about 900 kJ (4,473 and 4,439 vs 5,383 kJ placebo)	Healthy-weight men, n = 19	Bitter hop extract 500 mg, single dose
⁶	No effect at any dose or route	Healthy lean men, n = 26	Hop extract by tube into duodenum or stomach

^{63 6}

▲

Gut hormones (ghrelin, CCK, GLP-1, PYY)

Raised in trials

Hormones released by the gut that signal hunger (ghrelin) or fullness (CCK, GLP-1, PYY).

Low certainty

Results and what it means

Why it was measured

The proposed route by which bitter hop extract could reduce appetite.

Statistical vs. clinical meaning

Hormone changes were measured but did not translate into lower self-rated appetite.

Safety implication

None noted.

Study	Result	People	Product
⁶³	Pre-lunch ghrelin and post-meal CCK, GLP-1 and PYY rose vs placebo; insulin and GIP responses fell without a change in blood sugar	Healthy-weight men, n = 19	Bitter hop extract 500 mg
⁶	PYY rose modestly at the higher dose in the duodenum only	Healthy lean men	Hop extract by tube

^{63 6}

▲

Flow-mediated vasodilatation (FMD)

Raised in trials

How much an artery widens after a brief blockage of blood flow; a measure of blood-vessel lining health.

Very low certainty

Results and what it means

Why it was measured

A common test of early blood-vessel changes.

Statistical vs. clinical meaning

Acute change after one dose; no long-term benefit shown.

Safety implication

None noted.

Study	Result	People	Product
⁵⁹	Increased 30 and 120 minutes after the hop extract in smokers and non-smokers	Smokers n = 12, non-smokers n = 11	Isomerised hop extract, single dose

⁵⁹

▼

Inflammatory signals from white blood cells (ex vivo)

Lowered in trials

Cytokines released by blood cells after they are exposed to bacterial toxin in the lab.

Very low certainty

Results and what it means

Why it was measured

Used to test whether xanthohumol dampens inflammation signalling.

Statistical vs. clinical meaning

Lab-induced inflammation in blood cells from nine women; not a health outcome.

Safety implication

None noted.

Study	Result	People	Product
³⁰	Release was lower in cells taken after xanthohumol-rich hop extract vs placebo	Healthy normal-weight women, n = 9	Single dose 0.125 mg xanthohumol in a hop extract

³⁰

Safety

What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.

Main points to know 9

Hops can make you drowsy: avoid driving or machinery if you feel sleepy. The EU herbal monograph says hop preparations may impair the ability to drive and use machines, and that affected people should not drive or operate machinery. It lists undesirable effects as none known and says no case of overdose has been reported. In the 4-week valerian-hops trial in 184 adults there were no significant residual effects the next day, no serious adverse events and no rebound insomnia after stopping, but this was a combination product. Doctors or practitioners should be consulted if symptoms last more than two weeks. Authoritative guidance ^{16 41}
Sedation and depression: take extra care if you have low mood or take sedating medicines. The EU monograph we read has no separate depression warning, and in one 4-week pilot, scores for depression were lower on a hop extract than on placebo in healthy young adults who had at least mild symptoms. Some herb guides advise caution in depression with sedating herbs; we could not verify such wording in the EU monograph, so we treat it as a precaution, not a proven harm. Hops act on the brain's calming (GABA-A) system in lab tests, so adding them to sleeping pills, anti-anxiety medicines or alcohol could add to sleepiness in theory; no study has tested this in people. If you are depressed, see a doctor first and tell them about any hop or valerian products. Pharmacological theory ^{16 34 4 5}
Hops are a strong plant estrogen source: ask your doctor first if you have a hormone-sensitive condition. Hops contain 8-prenylnaringenin (8-PN), described as one of the most potent plant estrogens known. In breast-cell tests 8-PN switched on estrogen receptor signalling but also slowed cell division, and a hop extract reduced estrogen-induced change in breast cells; other lab work shows hop compounds can lower the estrogen-making enzyme aromatase. In animals 8-PN has estrogenic effects on the mammary gland. In women, a 12-week soy-hop trial found no change in womb lining thickness or hormone levels, and a 6-month beer trial found no change in sex hormones. No study followed breast or womb tissue in women for years. People with a history of breast, ovarian or womb cancer, endometriosis, fibroids, or who take tamoxifen or aromatase inhibitors should ask their doctor before using hop supplements or extracts. A review of Dutch and WHO adverse-reaction reports linked phytoestrogen products in general with postmenopausal bleeding, and hops were named in about a third of the Dutch reports. These are spontaneous reports, not rates. Pharmacological theory ^{31 9 26 39 32 60 58 69}
Pregnancy and breastfeeding: not recommended. The EU monograph says safety in pregnancy and breastfeeding has not been established, use is not recommended, and no fertility data exist. Genotoxicity, reproductive toxicity and cancer tests have not been done. One lab study on a placental cell line found no harm at concentrations up to 30 micrograms/ml, but its authors say studies in pregnant women are needed. This is about hop extracts and teas; drinking alcoholic beer in pregnancy is a separate problem we did not review. Authoritative guidance ^{16 54}
Dogs: hops are poisonous to dogs, and spent hops from home brewing are a known cause. Veterinary reports describe dogs that swallowed hops, mostly spent hops from brewing: a case series of five dogs (four Greyhounds) with fever, panting, seizures and four deaths; a 71-dog poison-control review (fever in 96%, 77% survived per its abstract); and a 177-dog review (95.2% of the 83 with known outcome survived; signs began mostly 2 to 8 hours after eating). The cause is not fully known; authors suggest a malignant-hyperthermia-like reaction. Keep hops, hop pellets, spent brewing hops and hop supplements away from dogs, and call a vet at once if a dog has eaten any. Case report ^{15 46 3}
Allergy: hop pollen and plant contact can cause skin and breathing reactions. Case reports describe hop-farm workers with airborne dermatitis, eyelid swelling and conjunctivitis, and one person with repeated whole-body hives, joint pain and fever from hop. A herbal sedative and a face cream containing hop extract were identified as sources of allergen in one case. A lab study found hop proteins react with antibodies to birch, mugwort and grass pollen, so people with pollen allergy might react. The EU monograph lists allergy to the plant as the only contraindication. These are cases and lab findings; how often it occurs is unknown. Case report ^{55 48 47 16}
Beer is not the same as a hop supplement, and alcohol brings its own risks. Most hop products in trials were capsules, tablets or extracts. Beer-type products in the trials were non-alcoholic beers. Alcoholic beer adds alcohol, which has its own effects on sleep, pregnancy, driving and medicines. In lab tests alcohol increased the calming effect of a hop compound on brain receptors. Reactions to beer are not always from hops: one reported anaphylaxis after wheat beer was traced to wheat, and hop tests were negative. Laboratory research ^{5 27 18 22}
Do not use medicinal hop products for more than two weeks without advice; children under 12 are not covered. The EU monograph says if symptoms last more than two weeks a doctor or qualified practitioner should be consulted. Use in children under 12 is not recommended because of lack of data. Trials ran 3 days to 6 months; xanthohumol alone was tested for 8 weeks at 24 mg a day with no serious adverse events, and a 24-week weight-loss trial of a bitter hop extract is the longest we found. Authoritative guidance ^{16 35 64}
A bitter hop extract can upset the stomach. In a single-day trial of 19 men, a 500 mg bitter hop extract caused nausea, bloating and stomach discomfort, with mild to severe stomach and gut symptoms with the quick-release capsule only. Symptoms are a reason to avoid concentrated bitter extracts on an empty stomach, but the trial gave no instruction on this and the other hop trials listed few problems. Controlled trial ^{63 6}

Side effects 8

Effect	How often	Severity and recovery	Evidence
Drowsiness and impaired driving EMA says hop preparations may impair driving; the monograph lists undesirable effects as none known. No residual effect was found the morning after in the valerian-hops trial.	Not established	moderate Not stated	Authoritative guidance ¹⁶
Stomach discomfort, nausea, bloating After a single 500 mg dose of bitter hop extract in 19 men; mild to severe stomach and gut symptoms with the quick-release capsule only.	Not established	mild to severe Not stated	Controlled trial ⁶³
Contact dermatitis, airborne dermatitis, conjunctivitis In a 57-year-old hop farmer; the herbal sedative and a cream containing hop extract also triggered relapses.	Not established	moderate Recurred after repeated exposure in one case	Case report ⁵⁵
Whole-body hives with joint pain and fever One patient, four episodes; wild hop was proven to be the trigger.	Not established	moderate Responded to corticosteroids	Case report ⁴⁸
Hyperthermia, panting, vomiting and seizures in dogs This is a pet poisoning, not a human effect. Four of five dogs died in the first case series; survival was 77% and 95.2% in the two larger reviews (the first abstract's number does not match its own counts).	Fever in 96% of 71 dogs; 74% of 177 dogs showed signs	serious Most survivors recovered fully within 24 hours; some dogs died	Case report ^{15 46 3}
Postmenopausal bleeding (phytoestrogen products in general) A scoping review linked products with assumed phytoestrogen activity with postmenopausal bleeding; hops are among those in Dutch reports but the review does not tie bleeding to hops alone.	Not established	moderate Not stated	Authoritative guidance ⁵⁸
Adverse event reports listed for hop products Reports are most often stomach and gut, skin, reproductive system and breast disorders; cannot show cause or frequency.	32.8% of 67 Dutch phytoestrogen reports named hops	not stated Not stated	Authoritative guidance ⁵⁸
No serious adverse events in short trials Xanthohumol 24 mg a day for 8 weeks in healthy adults and in Crohn's disease; valerian-hops for 4 weeks; soy-hop for 12 weeks.	58 non-serious events with xanthohumol vs 42 with placebo over 8 weeks (30 people)	not applicable Not applicable	Controlled trial ^{35 8 41 32}

Liver

We found no human case report of liver injury from hops. The NIH LiverTox page for hops is reported (in a search summary, not read directly because the page was blocked) to give it the lowest-risk rating, E (unlikely cause of clinically apparent liver injury). In an 8-week trial of pure xanthohumol (24 mg a day) the blood chemistry panels did not differ in any clinically relevant way from placebo; in Crohn's disease the blood marker GGT was lower than on placebo. In mice fed about 1000 mg/kg a day of xanthohumol for 3 weeks, no organ or liver damage was found. ^{44 35 8 14}

How often. No rate of liver injury could be given. Absence of reports is not proof of safety; the xanthohumol trials had 20 to 30 people in total.

Monitoring. No agency monitoring advice was found. People with liver disease should ask their doctor before regular use.

This is a safety connection. It is not evidence that Hops supports liver health.

Medicines and supplements 8

With	Why it matters	Importance	Evidence	What to do
Sleeping pills, benzodiazepines, other sedatives and alcohol prescription	In lab tests hop compounds (humulone, 6-prenylnaringenin) strengthen the brain's calming GABA-A receptor; ethanol enhanced the humulone effect and hop compounds added to each other.	No study in people tested hops with sedatives. EMA lists no interactions reported. Possible added sleepiness.	Pharmacological theory Very low certainty ^{16 4 5}	If you take sedatives or drink alcohol, talk to your doctor or pharmacist before adding hops. Do not drive if drowsy.
Valerian, kava and other sedating herbs supplement	Same calming-system theory; many hop products already contain valerian.	Valerian plus hops was tested together in trials without serious events, but stacking several sedating herbs has not been studied.	Pharmacological theory Very low certainty ^{41 4}	Do not stack several sedating herbs without advice.
Medicines broken down by CYP2C8, CYP2C9 or CYP2C19 prescription	In human enzyme tests a standardised hop extract at 5 micrograms/ml blocked CYP2C8 (93%), CYP2C9 (88%) and CYP2C19 (70%); the strongest blockers were isoxanthohumol and 8-prenylnaringenin.	The authors say this may affect the safety and effectiveness of CYP2C drugs. No human interaction study has been done, so the real-world importance is unknown. Examples of drugs cleared this way, such as the blood thinner warfarin and some seizure medicines, are our general pharmacology examples, not hop-specific tests.	Laboratory research Very low certainty ^{67 25}	If you take warfarin, seizure medicines or other drugs with a narrow safety margin, ask your pharmacist before using hop extracts.
Medicines broken down by CYP1A2 (for example caffeine-type drugs) prescription	The hop extract blocked CYP1A2 by 27% in the same lab test, with time-dependent inactivation seen only for this enzyme.	Smaller effect than for CYP2C; no human data.	Laboratory research Very low certainty ⁶⁷	Mention hops to your pharmacist if you take a drug that is cleared by CYP1A2.
Medicines cleared by glucuronidation (acetaminophen, morphine and hormones) prescription	In human liver microsomes valerian and valerian-hops extracts cut the making of acetaminophen, estradiol, morphine and testosterone glucuronides; the authors suspect valerenic acid from valerian.	Test-tube result on valerian-hops products; effect of hops alone unknown.	Laboratory research Very low certainty ²	No action beyond telling your pharmacist about valerian-hops products.
Hormone therapy, hormonal contraceptives, tamoxifen and aromatase inhibitors prescription	Hop 8-prenylnaringenin acts on estrogen receptors; hop compounds lowered aromatase activity in cells; 8-PN is cleared by CYP2C8/2C19.	No study tested this combination. A plant estrogen could add to or oppose these medicines in theory.	Pharmacological theory Very low certainty ^{9 39 25 69}	Ask your doctor first, especially if you take medicine for breast cancer.
Caffeine food	A valerian-hop extract reduced or blocked caffeine's brain-wave arousal in healthy volunteers.	A brain-wave finding with a combination product; shows opposing effects, not harm.	Controlled trial Very low certainty ⁵²	Coffee late in the day may work against a sleep product.
Drugs moved by the pumps P-glycoprotein and MRP1 prescription	In human cell tests 8-prenylnaringenin blocked both pumps (IC50 5.76 micromolar for MRP1) but did not make a cancer drug more toxic to resistant cells.	No human data.	Laboratory research Very low certainty ⁶⁶	No action; flagged for pharmacists.

Who should check first 8

Situation	Advice	Evidence
Allergy to hops, or earlier reaction to a hop product	Do not use. The EU monograph lists hypersensitivity to the plant as the contraindication.	Authoritative guidance ¹⁶
Pollen allergy (birch, mugwort, grass) with a history of reactions to plant products	Be careful; lab tests show hop proteins react with pollen-allergy antibodies. Not proven to cause reactions in people.	Laboratory research ⁴⁷
Pregnancy and breastfeeding	Use is not recommended; no safety or fertility data (EMA).	Authoritative guidance ^{16 54}
Children under 12	Not recommended: not enough data (EMA).	Authoritative guidance ¹⁶
Breast, ovarian or womb cancer (past or present), endometriosis, fibroids or other hormone-sensitive conditions	Ask your doctor before using hop extracts or supplements because 8-prenylnaringenin is a strong plant estrogen; no long-term human data exist.	Pharmacological theory ^{69 31 9}
Driving, machinery or work needing alertness	Do not drive or use machinery if drowsy (EMA).	Authoritative guidance ¹⁶
Depression or taking sedating medicine or alcohol	See a doctor before use (precaution; see key safety).	Pharmacological theory ^{16 4}
Dogs and pets at home	Keep hop products, hop pellets and spent brewing hops out of reach of dogs.	Case report ^{15 46 3}

Overdose, product quality and regulators

Summary. No human overdose has been reported (EMA). The best-documented poisoning is in dogs. Genotoxicity, reproductive toxicity and cancer tests have not been done (EMA).

Animal. In mice, feeding about 1000 mg/kg a day of xanthohumol for 3 weeks caused no organ or liver damage. In dogs, swallowing hops (mostly spent brewing hops) caused fever, fast breathing, vomiting and seizures; four of five dogs died in the first reported series.

Human doses studied. Trials gave hop extracts or products for single doses to 6 months; xanthohumol 24 mg a day for 8 weeks; 8-prenylnaringenin or 6-prenylnaringenin as a single 500 mg dose in 16 healthy volunteers with no safety signal stated in the abstract.

High dose or long term signals. No long-term human data on estrogen-like effects of hops on breast or womb tissue were found.

Overdose response. Humans: no case of overdose reported (EMA). Dogs: signs usually start within 2 to 8 hours; severe fever (above 41.4 C) was linked to death.

Genotoxicity. EMA says adequate tests on genotoxicity have not been performed.

Toxic plant parts. Hop cones (strobiles), including spent hops left over from brewing, are toxic to dogs. For people, handling the plant can cause contact allergy.

We did not find a quality or contamination study of hop products in the sources read.

Content of estrogenic compounds can vary. Hop extracts in trials were standardised to 8-prenylnaringenin or to bitter acids, and the cells and animals tests used extracts with chosen marker amounts. Whether ordinary supplements vary is not shown in the papers we read. A research group notes that standardising botanical extracts to several chemical markers matters for safety and activity. ^{65 28}

Many products combine hops with valerian or other herbs. The sleep trials used valerian-hops combinations and the menopause trials sometimes used soy-hop or other blends, so labels should be checked for all ingredients. ^{41 32}

Body	Action	Date
European Medicines Agency, Committee on Herbal Medicinal Products (HMPC) (European Union)	Community herbal monograph on Humulus lupulus L., flos (EMA/HMPC/682384/2013): traditional herbal medicine for relief of mild symptoms of mental stress and to aid sleep. Contraindication: allergy to the plant. Not recommended under 12 or in pregnancy and breastfeeding. May impair driving. EMA lists the monograph as having an ongoing call for scientific data. source	2014-05-06

When to get medical help

Hives, swelling of the face or lips, wheezing or trouble breathing after a hop product (allergy): get emergency help
A dog that has eaten hops, even a small amount, especially with panting, vomiting, restlessness or a fever: call a vet or animal poison line at once
Seizure, collapse or very high fever in a dog or person after hop exposure
Worsening low mood, hopelessness or thoughts of harming yourself while using any sedating herb: contact a doctor or a crisis line
Vaginal bleeding after menopause while using a hop or other plant-estrogen product: see a doctor
Severe drowsiness that makes driving or caring for children unsafe

Stop the supplement and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.

General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.

Frequently asked questions

Do hops help you sleep?

A little, in some trials, but the evidence is weak. Most sleep trials used valerian and hops together. The largest (184 adults) found modest self-reported improvement and few results that beat placebo, and sleep-lab recordings did not differ. A smaller trial found valerian-hops shortened sleep latency while valerian alone did not. No trial tested hops alone for insomnia. The EU lists hops as a traditional medicine to aid sleep, based on long use.

^{41 33 53 50 16}

Is valerian-and-hops better than hops alone?

We do not know. No trial compared them. In one trial the valerian-hops combination beat placebo while valerian alone did not, which hints that hops add something, but hops alone were not tested for insomnia.

^{33 41}

Do hops reduce anxiety or stress?

One 36-person pilot found lower anxiety, depression and stress scores after 4 weeks of hop extract than placebo in young adults with mild symptoms. Morning cortisol did not change. It has not been repeated, so the certainty is low. A review lists hops among plants that act on the brain's calming system, but gives no hops-specific figures in its abstract.

^{34 51}

Do hops help menopause hot flashes?

Results are mixed. Some small trials of hop extract beat placebo and some did not; a soy-hop combination beat placebo; and a review calls the data few and inconclusive. Hops contain a strong plant estrogen, so see the safety section first.

^{28 17 1 32 31}

Can I use hops if I have breast cancer or another hormone-sensitive condition?

Ask your doctor first. Hops contain 8-prenylnaringenin, described as one of the most potent plant estrogens. Cell and animal findings are mixed and no study has followed breast or womb tissue in women for years. Short trials saw no change in womb lining thickness or hormones. Also ask before using hops with tamoxifen or aromatase inhibitors.

^{31 9 26 32 69}

Can I take hops with sleeping pills, alcohol or other medicines?

Ask your pharmacist. The EU says no interactions have been reported, but no study tested this. In lab tests hop compounds strengthen the brain's calming system and alcohol added to that effect, so extra sleepiness is possible in theory. In test tubes a hop extract also blocked liver enzymes (CYP2C8, 2C9, 2C19) that clear some medicines; no human study confirms this.

^{16 4 5 67 2}

Are hops safe in pregnancy, breastfeeding or for children?

Not recommended. The EU says safety in pregnancy and breastfeeding is not established, no fertility data exist, and use under age 12 is not recommended. A placental cell test found no harm at the concentrations tested, but studies in pregnant women are needed.

^{16 54}

Are hops dangerous to dogs?

Yes. Veterinary reports describe dogs, especially after eating spent brewing hops, with fever, fast breathing, vomiting and seizures. In a case series four of five dogs died; larger reviews found most dogs survived with treatment, but some had severe fever and died. Keep hops and hop products away from dogs, and call a vet at once if a dog eats any.

^{15 46 3}

Is non-alcoholic beer or beer a good way to get the benefits?

No. Two small studies of non-alcoholic beer reported faster sleep onset but had no placebo drink. Beer contains many things besides hops, and alcoholic beer adds alcohol, which affects sleep, driving, pregnancy and medicines. In a lab test alcohol added to a hop compound's calming effect.

^{18 19 5}

Can hops cause an allergy?

Yes, in some people. Case reports describe skin and airborne reactions in hop farm workers and whole-body hives, and a herbal sedative and face cream with hop extract triggered one case. A lab study found hop proteins react with pollen antibodies. The EU lists allergy to the plant as the contraindication. How often it happens is unknown.

^{55 48 47 16}

Will hops make me drowsy, and can I drive?

They may. The EU says hop preparations may impair the ability to drive and use machines, and affected people should not drive. In the 4-week valerian-hops trial there were no significant residual effects the next day.

^{16 41}

Are hops safe if I am depressed?

Talk to your doctor first. Hops are sedating, and some herb guides advise caution in depression, but the EU monograph we read has no such warning, and a small pilot found lower depression scores on hops in healthy young adults with mild symptoms. Hops have not been tested in people with diagnosed depression.

^{16 34 4}

Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against PubMed records.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-25
Last substantive update: 2026-10-25
How we research: We searched PubMed, read the full EU herbal monograph on hop strobile, and checked plant names in GBIF and NCBI and compound IDs in PubChem. Only abstracts were read for nearly all studies. Some sources were not verified: the LiverTox page was blocked and is known only from a search summary, the German Commission E monograph is known only from one trial's authors, and no NCCIH, FDA, LactMed or WHO entry was read. Two dog-poisoning counts in one abstract do not match and are flagged. Certainty ratings are the compiler's own reading, not formal grades.
How we rate evidence: See "How we rate evidence" in the Evidence tab.
Independence: No product is promoted on this page. No affiliate links are shown. If one is added later it will be labelled and kept apart from the evidence.

Sources 69

Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.

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Where to buy

Check the label first. Whatever you buy, look for these:

The plant part and the extract type or ratio on the label
A standardized amount of the active compounds, where relevant
A third-party testing mark (USP, NSF or ConsumerLab)
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Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.