Stinging nettle (Urtica dioica) leaf.

Nettle Tea

Q: Is nettle tea caffeine-free?

Nettle is not a true tea from the tea plant. No source we read lists caffeine as a constituent of nettle leaf, and the EMA report names caffeic acid esters (a different compound) and traces of nicotine. We did not find a direct caffeine measurement for nettle tea, so this rests on the published constituent list.

Q: Does nettle tea work as a water pill?

Nettle leaf is a traditional water-increasing herb, and the EU accepts it for flushing the urinary tract in minor complaints on long use only. No human trial of the tea measured urine output. In rats, an extract given into a vein raised urine. The EU says not to use it if you have been told to limit fluids.

Q: Does nettle tea help with hay fever?

Not shown. Two small trials exist, and neither used tea. A freeze-dried nettle product was rated a little better than placebo in 1990. In a 2017 trial of nettle root tablets, the placebo helped symptoms as much as nettle.

Q: Does nettle tea help with arthritis or joint pain?

The EU accepts nettle leaf for minor joint pain on traditional use only. Trials used nettle sting on the skin or mixed products, not tea. The evidence is very low quality or cannot separate nettle from other ingredients.

Q: Is nettle tea good for the prostate?

The prostate research is on nettle root extract, which is a different product from leaf tea. Root trials show modest symptom score gains, and a review found no convincing evidence for nettle alone. See a doctor for urinary symptoms.

Q: Does nettle tea lower blood sugar or blood pressure?

Pooled trials in people with type 2 diabetes found lower fasting blood sugar and a small drop in the top blood pressure number with nettle products. Those products were mostly extracts or capsules, not tea. If you take diabetes or blood pressure medicine, ask your doctor or pharmacist before drinking nettle tea regularly.

Q: Is nettle tea safe in pregnancy or while breastfeeding?

The EU herbal committee says safety has not been established and use is not recommended. LactMed says there is only minimal scientific support for nettle as a milk-boosting herb. Ask your doctor, midwife or pharmacist.

Q: Can I give nettle tea to children?

The EU says use under age 12 is not recommended for lack of data. Ask a doctor.

Q: Does nettle tea interact with medicines?

The EU monograph says none reported, which is not the same as none exist. Possible added effects are described in theory or animals for water pills and blood pressure medicines. Nettle leaf contains some vitamin K, which German labels use to warn about warfarin-type medicines, although the EMA assessor judged the amount small. No source we read mentions lithium. Ask your pharmacist.

Q: Can nettle tea affect the liver or kidneys?

LiverTox says nettle extracts have not been linked to liver injury. The EU lists conditions where less fluid is advised, such as severe heart or kidney disease, as a contraindication. A food-safety review of wild plants raised an oxalic acid precaution for common lambsquarters, but not for nettle; it gives no oxalate figure for nettle.

Urtica dioica and Urtica urens (leaf) · also called Stinging nettle tea, nettle leaf tea, Urticae folium. Not the same as nettle root or nettle seed products.

Nettle tea is a herbal infusion of dried stinging nettle leaf. It is used traditionally for joint aches and to increase urine, and for hay fever and blood sugar. Almost no trials used the tea itself: most used extracts, capsules, root or mixed products, so the evidence for the tea is thin. The main cautions are pregnancy and breastfeeding, conditions where fluids are limited, and a possible added effect with water pills, blood pressure, diabetes and warfarin-type medicines.

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 Nettle Tea

Nettle tea is a herbal infusion of dried stinging nettle leaf (Urtica dioica or Urtica urens). It is not a true tea from the tea plant. The EU accepts it for minor joint pain and for increasing urine, on long use only. Trials of nettle products are small and mostly not of the tea. The main safety points are pregnancy, fluid restriction, allergy and possible added effects with some medicines.

What it is

Nettle tea is made from the dried leaf of stinging nettle. GBIF lists Urtica dioica L. and Urtica urens L. as accepted species of the nettle family. The EU monograph covers either species or a mix of both.

The EMA assessment report lists flavonoids (1 to 2% of the leaf), silicates (1 to 4%), chlorophyll, scopoletin, plant sterols and caffeic acid esters. It also lists traces of nicotine. It does not list caffeine, and we found no direct caffeine test, so we say only that no caffeine is listed.

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Tea, extract and root are different

The EU monograph lists nettle leaf as a herbal tea and also as liquid and dry extracts. Most of the trials we found used extracts or capsules (blood sugar), a root extract (the prostate and hay fever) or mixed products (joint pain). So a trial result for those does not tell you what the tea does.

Brewing also changes what ends up in the cup. The EMA report quotes a study that found far less sodium relative to potassium in a boiled nettle drink than in the plant itself. Nettle root, seed and the fresh sting are separate products again.

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What the research shows

We found no trial of nettle leaf tea for a health outcome. The EU accepts the leaf on long use only, and the EMA assessor says joint pain trials are not enough for a well-established use.

Pooled trials of nettle products in type 2 diabetes show lower fasting blood sugar, but the trials differ a lot. Hay fever, joint pain and prostate trials are small and use root, freeze-dried or mixed products. A 2000 review found no convincing evidence for nettle alone for the prostate. A cell-culture or animal result is not a result for people.

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Quality and purity

Studies of German medicinal teas, 19 of them nettle, found natural plant alkaloids in many products, and a second German study said Urtica dioica products were often above recommended values. Nettle also accumulates nitrate. In Polish samples nettle had the highest median mercury of five herbs, with most samples over the limit being wild-collected. An Iranian garden study found nettle took up cadmium strongly.

If you pick your own nettle, avoid roadsides and polluted soil. For shop tea, choose a label that names the plant and part.

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At a glance

Traditional uses history, not proof

The EU accepts nettle leaf as a traditional herbal medicine for minor joint pain and for increasing urine to flush the urinary tract in minor complaints, on long use only.
The EMA assessment report quotes older sources using it for arthritis, allergies, high blood pressure and diabetes. These are statements in the report, not tests.

Studied for research

Hay fever, very-low
Joint pain: nettle sting on the skin, very-low
Joint pain: nettle leaf by mouth, insufficient
Enlarged prostate (nettle root, not tea), low
Increasing urine (traditional use), insufficient
Type 2 diabetes and blood sugar, low
Blood pressure, very-low
Cholesterol and blood fats, very-low
Inflammation marker (CRP), very-low

Main compounds

Flavonoids (rutin and quercetin, kaempferol and isorhamnetin glycosides)
Caffeoylmalic acid (a caffeic acid ester; not caffeine)
Scopoletin, beta-sitosterol, silicates and chlorophyll

Common forms

Dried leaf tea (infusion)
Leaf extracts and capsules (different product)
Root extract (different product, studied for the prostate)

Research links: EMA: community herbal monograph on nettle leaf (2010) · EMA: assessment report on nettle leaf · Memorial Sloan Kettering: nettle · LiverTox: stinging nettle (abstract) · LactMed: stinging nettle (abstract) · Meta-analysis: nettle and metabolic profile in type 2 diabetes (abstract) · Research Library · Genes & Biomarkers Library

What it is and its history

Accepted scientific name: Urtica dioica
Naming authority: L.
Synonyms: Name: Urtica urens L.; Note: A separate species (small nettle). The EU monograph covers both species or a mix of the two, and the nettle tea page covers both.
Common names: Stinging nettle (English); Nettle leaf (English); Common nettle (English); Urticae folium (Latin (pharmacy name)); Ortie (feuille d') (French (EMA list)); Brennesselblätter (German (EMA list))
Family or group: Urticaceae (the nettle family)
Classification: Plantae > Tracheophyta > Magnoliopsida > Rosales > Urticaceae > Urtica > Urtica dioica
Native range: Not checked in the sources read.
Habitat: Not checked.
What it looks like: Roots: Not checked.; Stems: Not checked.; Leaves: The leaf is the part used for tea. The EMA assessment report describes stinging hairs on the plant.; Flowers: Not checked.; Fruit: Not checked.
Cultivation: Not checked.
Harvest and processing: The EU monograph describes the herbal substance as cut dried leaf. No source we read describes how any given tea bag was made.
Look-alikes and adulterants: Name: White deadnettle (Lamium album); Note: A non-stinging plant used as the placebo in a nettle sting trial. It is not a nettle.; Name: Nettle root and seed products; Note: Different parts, with different research (root for the prostate). Not covered by the leaf monograph.
Sustainability and conservation: Not checked.

Photographs

Stinging nettle leaf, close up — Stinging nettle (Urtica dioica) leaf.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
EU traditional herbal medicine	The EMA assessment report says nettle leaf has been in medical use for at least 30 years in the EU, as needed for a traditional herbal registration. It is accepted for minor joint pain and for increasing urine as an aid in minor urinary complaints.	s-ema-ar-nettle-leaf
Ancient and folk uses, as quoted in the EMA assessment report	The report quotes sources saying the ancient Greeks knew nettle and Dioscorides described it as a tonic and diuretic, and lists uses in several countries for arthritis, high blood pressure, allergies and diabetes. These are quoted statements in the report, not tests.	s-ema-ar-nettle-leaf
Hay fever and allergies in modern herbal practice	The EMA assessment report quotes a source saying nettle is used in some formulas for hay fever and other allergies. Not tested for tea.	s-ema-ar-nettle-leaf

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

What is inside, and how it may work

What it 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
Flavonoids (rutin and glycosides of quercetin, kaempferol, isorhamnetin) PubChem 5280805	Flavonoids	Leaf 1 to 2% of the leaf as flavonoids (EMA assessment report, quoting reference works).	Plant antioxidants; effect in tea not tested. ^{34 39}	Chemistry
Caffeoylmalic acid (caffeic acid ester) PubChem 6124299	Phenolic acid	Leaf Not given.	Called a main phenolic constituent. It is NOT caffeine. A leaf extract and this acid partly blocked leukotriene synthesis in test-tube cells, per the EMA report. ^{34 39}	Lab
Scopoletin PubChem 5280460	Coumarin	Leaf Not given.	Listed as characteristic of the leaf. ^{34 39}	Chemistry
Beta-sitosterol and its glucoside PubChem 222284	Plant sterol	Leaf Not given.	Listed as characteristic of the leaf. ^{34 39}	Chemistry
Silicates	Mineral compounds	Leaf 1 to 4% as SiO2, partly water-soluble (EMA assessment report).	Not tested for effect. ³⁴	Chemistry
Chlorophyll	Pigment	Leaf About 2.7% (EMA assessment report).	The green colour; no effect tested. ³⁴	Chemistry
Vitamin K	Vitamin	Leaf The EMA report quotes 0.16 to 0.64 mg per 100 g of leaf from the literature.	Relevant to warfarin-type medicines in theory; see Safety. ³⁴	Chemistry
Nicotine (traces) PubChem 89594	Alkaloid	Leaf Listed only as traces in the EMA report.	No effect from tea is described. ^{34 39}	Chemistry
Compounds in the stinging hairs	Irritant compounds	Stinging hairs Small amounts of acetylcholine, serotonin and formic acid (EMA report).	Cause the sting on the fresh plant. ³⁴	Chemistry

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Inflammation signals (leukotrienes, IL-1 beta, TNF-alpha)	5-lipoxygenase; cytokines	The EMA assessment report describes test-tube work in which a nettle leaf hydro-ethanolic extract (not tea) and its main phenolic acid partly blocked leukotriene synthesis. The assessor says an extract of nettle leaf might be useful for arthrosis, and that this supports the plausibility of the traditional use. Not shown in people who drink tea. ³⁴	Lab
Allergy pathways	Histamine-1 receptor, mast cell tryptase, COX-1, COX-2, HPGDS	A nettle extract blocked each of these in test-tube assays. ²⁰	Lab
Kidney salt and water handling	n/a	In rats, a water extract of the aerial parts given into a vein raised urine volume and sodium loss and lowered blood pressure. ²⁹	Animal research
Drug-metabolizing liver enzymes (P450)	Cytochrome P450 and P450 reductase	A leaf extract lowered liver P450 and P450 reductase activity in mice. ¹⁷	Animal research

Absorption, metabolism and elimination

Absorption: Not described for nettle tea in the sources read.
Distribution: Not described.
Metabolism: Not described. The EU monograph says pharmacokinetic data are not required for a traditional product.
Elimination: Not described.
Bioavailability: Not described.

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Isolated compounds versus whole extracts

Tea, extract and root are different products. The EU monograph lists the leaf as a herbal tea (cut dried leaf) and also separate liquid and dry leaf extracts made with water or alcohol. Most of the trials we found used extracts or capsules (blood sugar), a root extract (prostate, hay fever) or mixed products (joint pain), so results for them do not carry over to the tea. The EMA assessment report quotes a study that found a potassium to sodium ratio of 63 to 1 in the plant and 448 to 1 in a decoction (a boiled tea), so brewing changes what ends up in the cup. Nettle root, seed and the fresh sting are separate again.

Nutritional composition

The EMA assessment report lists nettle leaf as containing protein, fats, carbohydrates, chlorophyll, flavonoids, silicates and minerals including iron, calcium and potassium. It gives no amount for what ends up in a cup of tea. Nettle is not tea in the botanical sense: it does not come from the tea plant (Camellia sinensis). No source we read lists caffeine as a constituent of nettle leaf; the EMA report names caffeic acid esters (a different compound) and traces of nicotine. We did not find a direct caffeine measurement for nettle tea.

9benefits and uses looked at

42studies and sources checked

Low certaintybest evidence rating found

9lab markers tracked in trials

2 low certainty5 very low certainty2 not enough evidence

What was looked at

The 9 benefits and uses checked for Nettle Tea, each with how strong the evidence is. Tap one to open it.

Hay fever (allergic rhinitis)Very low certainty
Joint pain: nettle sting on the skinVery low certainty
Joint pain: nettle leaf taken by mouth (tea, extract or mixed product)Not enough evidence
Enlarged prostate (BPH): nettle root, a different product from leaf teaLow certainty
Increasing urine and flushing the urinary tract (traditional use)Not enough evidence
Type 2 diabetes and blood sugarLow certainty
Blood pressureVery low certainty
Cholesterol and blood fatsVery low certainty
Inflammation marker (CRP)Very low certainty

Lab markers tracked in the studies

International Prostate Symptom Score (IPSS)Peak urine flow (Qmax)Eosinophils in nasal smearJoint pain score (WOMAC pain and visual pain scales)Fasting blood glucoseHbA1cSystolic blood pressureTriglyceridesC-reactive protein (CRP)

What is Nettle Tea good for?

What the research shows for each use, and how strong it is. Almost none of it tested nettle leaf tea, so none of it proves a benefit from the tea. Read the Safety tab first if you are pregnant, breastfeeding, or take medicines.

Hay fever (allergic rhinitis)Very low certaintyTwo small placebo-controlled trials, neither of nettle tea. A freeze-dried nettle product was rated a little better than placebo in 1990. A 2017 trial of nettle root tablets found the placebo helped symptoms as much, though nasal eosinophils were lower with nettle. Joint pain: fresh nettle sting on the skinVery low certaintyA small thumb trial found less pain than with a placebo leaf. A knee pilot found no difference. A Cochrane review calls the evidence very low quality. This is not tea. Joint pain: nettle leaf by mouthNot enough evidenceNo trial tested nettle tea. Two trials of mixed products that contain nettle beat placebo, but nettle alone cannot be judged. The EU accepts the leaf for minor joint pain on traditional use only. Enlarged prostate: nettle root (a different product)Low certaintyTrials of nettle root extract found modest symptom score gains, with inconsistent flow results. A review found no convincing evidence for nettle alone. Root extract is not leaf tea. Increasing urine (traditional use)Not enough evidenceThe EU accepts nettle leaf as a tea to flush the urinary tract in minor complaints, on long use only. No human trial of the tea measured urine output. Rat work used an extract given into a vein. Type 2 diabetes and blood sugarLow certaintyTwo meta-analyses found lower fasting blood sugar with nettle products in type 2 diabetes. The trials differ widely and mostly use extracts or capsules, not tea. HbA1c results disagree. Blood pressureVery low certaintyA pooled analysis in people with type 2 diabetes found a small drop in the top number and none in the bottom number. One tiny trial reported drops. Rat work used an extract into a vein. Cholesterol and blood fatsVery low certaintyTriglycerides were lower in one pooled analysis of people with type 2 diabetes. Total, LDL and HDL cholesterol did not change significantly. Inflammation marker (CRP)Very low certaintyCRP was lower in one pooled analysis in people with type 2 diabetes. This is a blood marker, not a proven health gain.

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.

Hay fever (allergic rhinitis)

Very low certainty

Two small placebo-controlled trials were done, and neither used nettle leaf tea. One older trial of a freeze-dried nettle product rated it a little better than placebo. A newer trial of nettle root tablets found the placebo helped symptoms just as much.

4 studiesAmounts are not given here.

Studies, doses and limits

What the trials found

Two randomized trials (1990, 2017), one of a freeze-dried product and one of root extract tablets.

Results

1990: of 98 people who started, 69 finished; nettle was rated higher than placebo overall and only slightly higher in diaries. 2017: of 74 who started, 40 finished; symptoms improved in both groups (so the placebo did as well); nasal eosinophils were lower with nettle (P < .01); IgE and two interleukins did not change; interferon gamma differed (P = 0.017).

Effect sizes as reported

No numbers in the 1990 abstract. 2017: symptom change similar in both groups.

Why this rating

Two small trials with many dropouts, products that are not tea, and a placebo effect as large as the nettle effect in the newer one.

Form and dose studied

Amounts are not given here.

Who was studied

Adults with allergic rhinitis.

Limits

No trial of nettle tea. One trial gives no numbers. Root and freeze-dried leaf products are different from tea.

Why researchers looked

Nettle is a traditional hay fever remedy, and in test-tube work an extract blocked some allergy pathways.

Traditional use

The EMA assessment report notes that nettle leaf has been used for hay fever and allergies in several traditions. That is long use, not a test.

Proposed mechanism Lab

In test-tube assays a nettle extract blocked the histamine-1 receptor, mast cell tryptase and inflammation enzymes. This has not been shown to happen in people who drink the tea.

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

Nettle pollen can itself cause hay fever in a few people; see Safety. Skin reactions are possible.

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Joint pain: nettle sting on the skin

Very low certainty

Two small trials looked at fresh nettle on the skin. A thumb trial found less pain than with a placebo leaf. A knee pilot found no difference. A Cochrane review calls the evidence very low quality. None of this is about tea.

3 studiesFresh leaf touched to the skin for a week. Amounts are not given here.

Studies, doses and limits

What the trials found

Two randomized trials (27 and 42 people) and one Cochrane review of topical herbs for osteoarthritis.

Results

Thumb or finger osteoarthritis (27 people, crossover): after one week pain and disability scores fell more with nettle than with white deadnettle leaf (P = 0.026 and P = 0.0027). Knee osteoarthritis (42 people, pilot): pain fell by 1.7 points with nettle and 1.6 with the placebo plant. The 2013 Cochrane review (7 studies, 785 people, six different plant products) says it is uncertain whether stinging nettle leaf helps, because the evidence is very low quality, and found no serious side effects.

Effect sizes as reported

Thumb: P = 0.026 pain, P = 0.0027 disability. Knee: 1.7 (95% CI 0.6 to 2.9) vs 1.6 (0.5 to 2.7).

Why this rating

Two very small trials that disagree, one a feasibility pilot, and a systematic review that rates the evidence very low.

Form and dose studied

Fresh leaf touched to the skin for a week. Amounts are not given here.

Who was studied

Adults with hand or knee osteoarthritis.

Limits

Not tea. A stinging plant is hard to blind. Short trials.

Why researchers looked

Nettle sting has been used for arthritis for a very long time, and trial authors wanted to test it.

Traditional use

Stinging yourself with fresh nettle for arthritis pain is an old folk practice, described in the trial papers as an ancient therapy.

Proposed mechanism Hypothesis

Not shown. The sting itself may act as a counterirritant, which the Cochrane review says is how some topical plant products work in part.

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

The sting itself is a minor irritation in these trials. This is not a tea use.

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Joint pain: nettle leaf taken by mouth (tea, extract or mixed product)

Not enough evidence

No trial tested nettle leaf tea for joint pain. Two trials tested mixed products that contain nettle, and both beat placebo, but nettle alone cannot be judged from them. The EU accepts the leaf for minor joint pain on traditional use only.

5 studiesAmounts are not given here.

Studies, doses and limits

What the trials found

Two randomized trials of mixed products, one narrative review, and the EU monograph and assessment report.

Results

Phytalgic (fish oil, vitamin E and nettle), 81 people, 3 months: painkiller use 6.5 vs 16.5 tablets a week and NSAID use 0.4 vs 1.0 daily doses compared with placebo. MA212 (rosehip, nettle leaf extract, devil's claw root extract and vitamin D), 92 people with knee osteoarthritis, 12 weeks: pain score fell 29.87 points vs 10.23 with placebo. A 2007 review says clinical evidence beyond doubt is lacking. The EMA assessor says trials are not enough for a well-established use but support the plausibility of the traditional use.

Effect sizes as reported

Painkillers 6.5 vs 16.5 per week (P < 0.001); pain score change 29.87 vs 10.23.

Why this rating

No trial of nettle tea, and the two trials used mixtures, so any benefit cannot be credited to nettle.

Form and dose studied

Amounts are not given here.

Who was studied

Adults with knee or hip osteoarthritis.

Limits

Mixed products, short trials, no tea. Funding is not stated in the abstracts.

Why researchers looked

Nettle leaf is a traditional remedy for arthritis and rheumatism.

Traditional use

The EU lists nettle leaf as a traditional herbal medicine for minor joint pain, based on at least 30 years of use.

Proposed mechanism Lab

A nettle leaf extract and one of its main phenol compounds partly blocked inflammation signals in test-tube cells, as reported in the EMA assessment report. This was not tested with tea.

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

The EU says to see a doctor if joint pain comes with swelling, redness or fever, and not to use it beyond 4 weeks for this purpose.

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Enlarged prostate (BPH): nettle root, a different product from leaf tea

Low certainty

Trials of nettle root extract found modest symptom score improvements. Results are not consistent, and a review found no convincing evidence for nettle alone. This is root, not leaf, so it says little about tea.

4 studiesAmounts are not given here.

Studies, doses and limits

What the trials found

Three randomized trials of nettle (620, 246 and 60 men) and one older review.

Results

620 men (6 months): symptom score (IPSS) fell from 19.8 to 11.8 with nettle and from 19.2 to 17.7 with placebo (P = 0.002); peak flow rose 8.2 vs 3.4 mL/s; no side effects were found. 246 men (12 months, root extract): IPSS fell from 18.7 to 13.0 vs 18.5 to 13.8 (P = 0.0233); peak flow and residual urine did not differ from placebo. 60 men (12 weeks, root extract): the abstract reports an intermediate effect on IPSS, with no figures. A 2000 review of 44 studies of six plant products says there is no convincing evidence for Urtica dioica alone.

Effect sizes as reported

IPSS 19.8 to 11.8 vs 19.2 to 17.7 (P = 0.002); 18.7 to 13.0 vs 18.5 to 13.8 (P = 0.0233).

Why this rating

Consistent small gains in symptom score, but peak flow results disagree between trials, the largest trial is a single-author study, and the only review is from 2000. The products are root, not tea.

Form and dose studied

Amounts are not given here.

Who was studied

Men with symptoms from an enlarged prostate.

Limits

Root extract. Not tea. Placebo groups improved too. Funding is not stated in the abstracts.

Why researchers looked

Men with an enlarged prostate often look for plant remedies, and nettle root is a common one.

Traditional use

The EU lists the root, not the leaf, for urinary symptoms linked to an enlarged prostate. That is a different product from leaf tea.

Proposed mechanism Hypothesis

Not shown in these papers.

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

Urinary symptoms need a doctor first. Blood in the urine, fever or pain on passing urine means seeing a doctor.

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Increasing urine and flushing the urinary tract (traditional use)

Not enough evidence

Nettle leaf is a traditional water-increasing herb, and the EU accepts it for that on long use alone. We found no human trial of the tea measuring urine output. The only measured effect is in rats, given a water extract by drip into a vein.

3 studiesAmounts are not given here.

Studies, doses and limits

Results

Rats (extract given into a vein): urine volume rose by 11% at the low dose and 84% at the high dose; sodium loss by 28% and 143%; blood pressure fell by 15% and 38%. The high-dose blood pressure effect lasted, which the authors say may be toxic. The EMA calls the traditional use plausible but not proven in trials.

Effect sizes as reported

Rats only: urine +11% and +84%.

Why this rating

No human trial found; only animal data with a route of giving that tea does not use.

Form and dose studied

Amounts are not given here.

Who was studied

No human population studied.

Limits

Animal study. Traditional use is not trial evidence.

Why researchers looked

It is one of the oldest uses of nettle leaf.

Traditional use

The EU accepts nettle leaf, as a herbal tea, to increase urine and flush the urinary tract in minor urinary complaints. It says this rests only on long-standing use.

Proposed mechanism Animal research

In anaesthetised rats, a water extract of the aerial parts given into a vein raised urine volume and sodium loss and lowered blood pressure.

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

The EU says not for people told to limit fluids, for example with severe heart or kidney disease, and to see a doctor if there is fever, pain on passing urine, spasm or blood in the urine.

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Type 2 diabetes and blood sugar

Low certainty

Two meta-analyses found nettle products lowered fasting blood sugar in people with type 2 diabetes. The trials differ a lot, mostly use extracts or capsules, and none is clearly a tea.

5 studiesAmounts are not given here.

Studies, doses and limits

What the trials found

Two meta-analyses (13 and 8 trials) and two single trials of extracts.

Results

13 trials: fasting glucose fell by 17.17 mg/dl and HbA1c by 0.93, with insulin unchanged (very high heterogeneity). 8 trials (401 people): fasting glucose fell by 18.01 mg/dl, but HbA1c (-0.77%), insulin and the insulin resistance index did not change significantly. A 92-person trial of leaf extract capsules taken with usual drugs for 3 months found lower fasting glucose, 2-hour glucose and HbA1c than placebo.

Effect sizes as reported

Fasting glucose -17.17 mg/dl (95% CI -26.60 to -7.73) and -18.01 mg/dl (-30.04 to -5.97); HbA1c -0.93 (-1.66 to -0.17) in one review and -0.77% (-1.77 to 0.22, not significant) in the other.

Why this rating

Consistent drops in fasting glucose across trials, but very high heterogeneity (I2 about 93 to 95%), small trials, extract products, and disagreement on HbA1c.

Form and dose studied

Amounts are not given here.

Who was studied

Adults with type 2 diabetes, some already on drugs.

Limits

Not tea. Preparations differ. Heterogeneity very high. Funding not stated in the abstracts.

Why researchers looked

Nettle leaf is a traditional diabetes remedy, and lab work suggests it may affect sugar digestion and insulin release.

Traditional use

The EMA assessment report notes nettle leaf is used in several traditions for diabetes. That is long use, not a test.

Proposed mechanism Lab

One trial paper says nettle leaves have insulin-releasing, PPAR-gamma and alpha-glucosidase-blocking effects in lab work. Not shown in people.

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

If you take diabetes medicines, ask your doctor or pharmacist before adding nettle. Low blood sugar is possible in theory.

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Blood pressure

Very low certainty

A meta-analysis in people with type 2 diabetes found a small drop in the top blood pressure number and none in the bottom number. A tiny Lebanese trial reported drops. Rat studies show a drop with an extract given into a vein.

4 studiesAmounts are not given here.

Studies, doses and limits

What the trials found

One meta-analysis (in people with type 2 diabetes) and one very small trial in mild hypertension.

Results

Meta-analysis: systolic blood pressure fell by 5.03 mmHg; diastolic by 1.35 mmHg, which was not significant. Lebanese trial: 29 people with mild high blood pressure in four groups; the abstract reports drops for nettle with no figures. Rats: blood pressure fell by 15% and 38% with a water extract given into a vein.

Effect sizes as reported

Systolic -5.03 mmHg (95% CI -8.15 to -1.91); diastolic -1.35 mmHg (-2.86 to 0.17).

Why this rating

A small pooled effect in diabetic patients only, one trial of about seven people per group, and the rest animal data.

Form and dose studied

Amounts are not given here.

Who was studied

Adults with type 2 diabetes; adults with mild hypertension.

Limits

Not clearly tea. The blood pressure trial is tiny and does not describe the preparation.

Why researchers looked

Nettle is a traditional remedy for high blood pressure and also increases urine in animals.

Traditional use

The EMA assessment report notes the leaf has been used for high blood pressure in several traditions.

Proposed mechanism Animal research

In rats an extract lowered blood pressure along with raising urine volume. Not shown in people who drink tea.

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

Do not stop or change blood pressure medicine because of nettle. Ask your doctor or pharmacist.

^{28 24 29 34}

Cholesterol and blood fats

Very low certainty

In people with type 2 diabetes, triglycerides were lower with nettle in one meta-analysis, but total, LDL and HDL cholesterol did not change significantly. A small trial of an alcohol-water extract found better triglycerides and HDL.

2 studiesAmounts are not given here.

Studies, doses and limits

What the trials found

One meta-analysis (13 trials) and one trial of 50 women, all in type 2 diabetes.

Results

Meta-analysis: triglycerides fell by 26.94 mg/dl; total cholesterol (-6.39), LDL (-1.30) and HDL (+6.95) did not change significantly. 50 women, 8 weeks, alcohol-water extract: triglycerides fell and HDL rose compared with control.

Effect sizes as reported

Triglycerides -26.94 mg/dl (95% CI -52.07 to -1.82; I2 90%).

Why this rating

Wide confidence interval, very high heterogeneity, and only one other small trial.

Form and dose studied

Amounts are not given here.

Who was studied

Adults with type 2 diabetes.

Limits

Not tea. People without diabetes are not covered.

Why researchers looked

Blood fats are often checked in the same trials as blood sugar.

Proposed mechanism Hypothesis

Not shown in people.

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

Do not change cholesterol medicine because of nettle.

^{28 2}

Inflammation marker (CRP)

Very low certainty

A meta-analysis found lower CRP, a blood marker of inflammation, in people with type 2 diabetes. A small root-extract prostate trial also reported a small effect on a related marker. Lower CRP is a lab result, not a proven health gain.

2 studiesAmounts are not given here.

Studies, doses and limits

What the trials found

One meta-analysis and one small trial of root extract.

Results

Meta-analysis (13 trials, type 2 diabetes): CRP fell by 1.09 mg/dl. Prostate trial of root extract (60 men): the abstract reports a small effect on hs-CRP with no figures.

Effect sizes as reported

CRP -1.09 mg/dl (95% CI -1.64 to -0.53; I2 0%).

Why this rating

A lab marker in one group of patients, with no link shown to feeling better.

Form and dose studied

Amounts are not given here.

Who was studied

Adults with type 2 diabetes; men with an enlarged prostate.

Limits

Lab marker only. Not tea.

Why researchers looked

Nettle is traditionally called anti-inflammatory.

Proposed mechanism Hypothesis

Not shown. The papers measure blood markers only.

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

^{28 1}

Connections to the rest of health

How Nettle Tea 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
Immune Support	Potential benefit	Very low certainty	Hay fever (allergic rhinitis): Two small placebo-controlled trials were done, and neither used nettle leaf tea. One older trial of a freeze-dried nettle product rated it a little better than placebo. A newer trial of nettle root tablets found the placebo helped symptoms just as much.	^{15 3 20 34}
Seasonal Wellness	Potential benefit	Very low certainty	Hay fever (allergic rhinitis): Two small placebo-controlled trials were done, and neither used nettle leaf tea. One older trial of a freeze-dried nettle product rated it a little better than placebo. A newer trial of nettle root tablets found the placebo helped symptoms just as much.	^{15 3 20 34}
Joint Support	Traditional use	Very low certainty	Joint pain: nettle sting on the skin: Two small trials looked at fresh nettle on the skin. A thumb trial found less pain than with a placebo leaf. A knee pilot found no difference. A Cochrane review calls the evidence very low quality. None of this is about tea. Joint pain: nettle leaf taken by mouth (tea, extract or mixed product): No trial tested nettle leaf tea for joint pain. Two trials tested mixed products that contain nettle, and both beat placebo, but nettle alone cannot be judged from them. The EU accepts the leaf for minor joint pain on traditional use only.	^{18 19 6 10 16 7 35 34}
Inflammation Balance	Traditional use	Very low certainty	Joint pain: nettle sting on the skin: Two small trials looked at fresh nettle on the skin. A thumb trial found less pain than with a placebo leaf. A knee pilot found no difference. A Cochrane review calls the evidence very low quality. None of this is about tea.	^{18 19 6}
Mens Vitality	Potential benefit	Low certainty	Enlarged prostate (BPH): nettle root, a different product from leaf tea: Trials of nettle root extract found modest symptom score improvements. Results are not consistent, and a review found no convincing evidence for nettle alone. This is root, not leaf, so it says little about tea.	^{21 25 1 32}
Healthy Aging	Potential benefit	Low certainty	Enlarged prostate (BPH): nettle root, a different product from leaf tea: Trials of nettle root extract found modest symptom score improvements. Results are not consistent, and a review found no convincing evidence for nettle alone. This is root, not leaf, so it says little about tea.	^{21 25 1 32}
Mens Vitality	Traditional use	Not enough evidence	Increasing urine and flushing the urinary tract (traditional use): Nettle leaf is a traditional water-increasing herb, and the EU accepts it for that on long use alone. We found no human trial of the tea measuring urine output. The only measured effect is in rats, given a water extract by drip into a vein.	^{29 35 34}
Blood Sugar Balance	Potential benefit	Low certainty	Type 2 diabetes and blood sugar: Two meta-analyses found nettle products lowered fasting blood sugar in people with type 2 diabetes. The trials differ a lot, mostly use extracts or capsules, and none is clearly a tea.	^{28 33 11 2 34}
Metabolic Health	Potential benefit	Low certainty	Type 2 diabetes and blood sugar: Two meta-analyses found nettle products lowered fasting blood sugar in people with type 2 diabetes. The trials differ a lot, mostly use extracts or capsules, and none is clearly a tea. Cholesterol and blood fats: In people with type 2 diabetes, triglycerides were lower with nettle in one meta-analysis, but total, LDL and HDL cholesterol did not change significantly. A small trial of an alcohol-water extract found better triglycerides and HDL.	^{28 33 11 2 34}
Blood Pressure Support	Potential benefit	Very low certainty	Blood pressure: A meta-analysis in people with type 2 diabetes found a small drop in the top blood pressure number and none in the bottom number. A tiny Lebanese trial reported drops. Rat studies show a drop with an extract given into a vein.	^{28 24 29 34}
Heart Health	Potential benefit	Very low certainty	Blood pressure: A meta-analysis in people with type 2 diabetes found a small drop in the top blood pressure number and none in the bottom number. A tiny Lebanese trial reported drops. Rat studies show a drop with an extract given into a vein. Cholesterol and blood fats: In people with type 2 diabetes, triglycerides were lower with nettle in one meta-analysis, but total, LDL and HDL cholesterol did not change significantly. A small trial of an alcohol-water extract found better triglycerides and HDL.	^{28 24 29 34 2}
Cholesterol Balance	Potential benefit	Very low certainty	Cholesterol and blood fats: In people with type 2 diabetes, triglycerides were lower with nettle in one meta-analysis, but total, LDL and HDL cholesterol did not change significantly. A small trial of an alcohol-water extract found better triglycerides and HDL.	^{28 2}
Inflammation Balance	Biological association	Very low certainty	Inflammation marker (CRP): A meta-analysis found lower CRP, a blood marker of inflammation, in people with type 2 diabetes. A small root-extract prostate trial also reported a small effect on a related marker. Lower CRP is a lab result, not a proven health gain.	^{28 1}

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Respiratory System	Biological association	Very low certainty	Studied for: Hay fever (allergic rhinitis)	^{15 3 20 34}
Immune System	Biological association	Very low certainty	Studied for: Hay fever (allergic rhinitis) Studied for: Inflammation marker (CRP)	^{15 3 20 34 28 1}
Musculoskeletal System	Biological association	Very low certainty	Studied for: Joint pain: nettle sting on the skin Studied for: Joint pain: nettle leaf taken by mouth (tea, extract or mixed product)	^{18 19 6 10 16 7 35 34}
Urinary System	Biological association	Low certainty	Studied for: Enlarged prostate (BPH): nettle root, a different product from leaf tea Studied for: Increasing urine and flushing the urinary tract (traditional use)	^{21 25 1 32 29 35 34}
Reproductive System	Biological association	Low certainty	Studied for: Enlarged prostate (BPH): nettle root, a different product from leaf tea	^{21 25 1 32}
Endocrine System	Biological association	Low certainty	Studied for: Type 2 diabetes and blood sugar	^{28 33 11 2 34}
Metabolism Weight	Biological association	Low certainty	Studied for: Type 2 diabetes and blood sugar Studied for: Cholesterol and blood fats	^{28 33 11 2 34}
Cardiovascular System	Biological association	Very low certainty	Studied for: Blood pressure Studied for: Cholesterol and blood fats	^{28 24 29 34 2}

C. Body parts and organs

Connected to	Kind of connection	Evidence status	Context	Studies
Kidneys and urinary tract	Biological association	Not enough evidence	Traditional water-increasing use; EU contraindication where less fluid is recommended; no human trial of urine output. Traditional water-increasing use; no human trial of urine output. Preparation or compound: Nettle leaf tea	^{35 29}
Skin	Adverse effect or risk	Low certainty	Itching, rash and hives listed by the EU; one newborn case after nettle water. Preparation or compound: Nettle leaf, tea or nettle water	^{35 31}

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
International Prostate Symptom Score (IPSS)	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{21 25 1}
Peak urine flow (Qmax)	Biological association	Low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	^{21 25}
Eosinophils in nasal smear	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	³
Joint pain score (WOMAC pain and visual pain scales)	Biological association	Very low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	^{18 19}
Fasting blood glucose	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{28 33 11}
HbA1c	Biological association	Low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	^{28 33 11}
Systolic blood pressure	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	²⁸
Triglycerides	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{28 2}
C-reactive protein (CRP)	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	²⁸

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Flavonoids (rutin and glycosides of quercetin, kaempferol, isorhamnetin)	Biological association	Chemistry	Plant antioxidants; effect in tea not tested. Preparation or compound: Leaf	^{34 39}
Caffeoylmalic acid (caffeic acid ester)	Biological association	Lab	Called a main phenolic constituent. It is NOT caffeine. A leaf extract and this acid partly blocked leukotriene synthesis in test-tube cells, per the EMA report. Preparation or compound: Leaf	^{34 39}
Scopoletin	Biological association	Chemistry	Listed as characteristic of the leaf. Preparation or compound: Leaf	^{34 39}
Beta-sitosterol and its glucoside	Biological association	Chemistry	Listed as characteristic of the leaf. Preparation or compound: Leaf	^{34 39}
Silicates	Biological association	Chemistry	Not tested for effect. Preparation or compound: Leaf	³⁴
Chlorophyll	Biological association	Chemistry	The green colour; no effect tested. Preparation or compound: Leaf	³⁴
Vitamin K	Biological association	Chemistry	Relevant to warfarin-type medicines in theory; see Safety. Preparation or compound: Leaf	³⁴
Nicotine (traces)	Biological association	Chemistry	No effect from tea is described. Preparation or compound: Leaf	^{34 39}
Compounds in the stinging hairs	Biological association	Chemistry	Cause the sting on the fresh plant. Preparation or compound: Stinging hairs	³⁴

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 9 lab markers

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

Metabolic21 Inflammatory1 Other32

The evidence

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

Evidence by outcome

Hay fever (allergic rhinitis) 4 studies Very low certainty Joint pain: nettle sting on the skin 3 studies Very low certainty Joint pain: nettle leaf taken by mouth (tea, extract or mixed product) 5 studies Not enough evidence Enlarged prostate (BPH): nettle root, a different product from leaf tea 4 studies Low certainty Increasing urine and flushing the urinary tract (traditional use) 3 studies Not enough evidence Type 2 diabetes and blood sugar 5 studies Low certainty Blood pressure 4 studies Very low certainty Cholesterol and blood fats 2 studies Very low certainty Inflammation marker (CRP) 2 studies Very low certainty

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 read PubMed abstracts of 33 papers, the PubMed records for LiverTox and LactMed, and the EMA monograph, EMA assessment report and Memorial Sloan Kettering page in full. We checked the plant name in GBIF and NCBI Taxonomy and compounds in PubChem. Certainty ratings are the compiler's own reading. Funding is not stated in most abstracts. No study is cited that we could not verify.

Study library: every study we checked 42

Design Research type Year from Search

Study	Design	People	Product, dose, length	Result
Akbar Karami 2020 Urtica Dioica Root Extract on Clinical and Biochemical Parameters in Patients with Benign Prostatic Hyperplasia, Randomized Controlled Trial. Pak J Biol Sci · PMID 32981268 · DOI	Randomized controlled trial	60 60 men with BPH	Nettle ROOT extract tablets root Not given here 12 weeks · vs Placebo tablets	The abstract says nettle root extract had an intermediate effect on IPSS, a small effect on hs-CRP and an intermediate-to-large effect on MDA and SOD. Other measures were negligible or not significant. No side effects were seen. Intermediate effect on IPSS (no figures in the abstract). Methods, limits and funding Outcomes: IPSS; hs-CRP, MDA and SOD in blood Limitations: Small trial. Root extract, not leaf tea. Blood markers are not the same as feeling better. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Amiri Behzadi 2016 Effects of Urtica dioica supplementation on blood lipids, hepatic enzymes and nitric oxide levels in type 2 diabetic patients: A double blind, randomized clinical trial. Avicenna J Phytomed · PMID 28078249	Randomized controlled trial	50 50 women with type 2 diabetes	Hydro-alcoholic (water and alcohol) extract of Urtica dioica Not given here 8 weeks · vs Placebo	After 8 weeks fasting glucose, triglycerides and SGPT fell, and HDL, nitric oxide and SOD rose, compared with the control group. Several blood measures better than control; no figures in the abstract. Methods, limits and funding Outcomes: Fasting glucose, triglycerides, liver enzymes, HDL, LDL, antioxidant and nitric oxide markers Limitations: Small trial in women only. An alcohol-water extract, not a tea. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Bakhshaee 2017 Efficacy of Supportive Therapy of Allergic Rhinitis by Stinging Nettle (Urtica dioica) root extract: a Randomized, Double-Blind, Placebo- Controlled, Clinical Trial. Iran J Pharm Res · PMID 29844782	Randomized controlled trial	74 74 people with allergic rhinitis and a positive skin prick test; 40 finished	Nettle ROOT extract tablets root (not leaf) Not given here 1 month · vs Placebo tablets	Symptoms improved in both groups (P < .001), so the placebo did as well. Nasal eosinophils fell with nettle (P < .01). IgE, IL-4 and IL-5 did not change (P > .1). Interferon gamma differed between the groups after treatment (P = 0.017). Symptom score: same improvement with placebo. Nasal eosinophils lower with nettle (P < .01). Methods, limits and funding Outcomes: Symptom score (SNOT-22), nasal smear eosinophils, serum IgE and interleukins Limitations: Root extract tablets, not leaf tea. 34 of 74 did not finish. The authors say the limits call for larger, longer studies. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Boari 2013 Effect of cooking methods on antioxidant activity and nitrate content of selected wild Mediterranean plants. Int J Food Sci Nutr · PMID 23701122 · DOI	Other plant	Eight wild edible plants including Urtica dioica	Raw and cooked wild plants leaf as food Not given here	Boiling lowered nitrate in all species except asparagus, and wiped out the measured antioxidant activity in Urtica dioica (100% loss on a dry weight basis). Boiling cuts nitrate; in nettle it also cut antioxidant activity. Methods, limits and funding Outcomes: Antioxidant activity and nitrate after boiling, steaming and microwaving Limitations: Cooking a food, not brewing a tea. It does not give nettle nitrate amounts in its abstract. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Brodziak-Dopierała 2026 Analysis of Mercury Content in Medicinal Plants Popular in Poland. Molecules · PMID 42883333 · DOI	Other	Five Polish medicinal plants, wild-collected and as commercial herbal teas	Dried plant material and herbal teas leaf and other parts Not given here	Common nettle had the highest median mercury (23.80 micrograms per kg) of the five plants. Overall, 32% of all samples exceeded the permitted limit, mostly self-collected ones. The authors say that self-collecting nettle may carry a mercury risk. Nettle median 23.80 micrograms per kg; 32% of all samples above the limit. Methods, limits and funding Outcomes: Mercury content compared with the EU limit Limitations: Poland only. The abstract does not split commercial tea from wild samples for nettle. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Cameron 2013 Topical herbal therapies for treating osteoarthritis. Cochrane Database Syst Rev · PMID 23728701 · DOI	Systematic review	785 Seven studies of six topical plant products in osteoarthritis (785 people)	Topical herbal products, including stinging nettle leaf various Not given here various · vs Placebo or active comparison	The review says it is uncertain whether stinging nettle leaf on the skin helps osteoarthritis, because the evidence is very low quality and comes from single trials. No serious side effects were reported. Uncertain for nettle leaf (very low quality evidence). Methods, limits and funding Outcomes: Pain and function in osteoarthritis Limitations: Covers products put on the skin. Its search ended in 2013. It says that more high-quality trials are needed. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Chrubasik 2007 A comprehensive review on nettle effect and efficacy profiles, Part I: herba urticae. Phytomedicine · PMID 17493795 · DOI	Narrative review	Review of nettle herb (aerial parts) studies	Nettle herb preparations aerial parts (herb) Not given here	The authors say nettle herb is recommended for arthritis and urinary tract complaints. They conclude that some anti-inflammatory properties are suggested, but that clinical evidence beyond doubt is lacking. Clinical evidence beyond doubt is lacking. Methods, limits and funding Outcomes: Anti-inflammatory and other effects Limitations: Narrative review from 2007. Does not pool results. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Easton 2021 Stinging Nettle (Urtica dioica): An Unusual Case of Galactorrhea. Am J Case Rep · PMID 34876549 · DOI	Case report	1 A 30-year-old woman with milk discharge (galactorrhea)	Stinging nettle supplement (taken for environmental allergies) Not given here About 1 month	The milk discharge resolved completely one week after nettle was stopped. Pregnancy test, prolactin and thyroid tests were normal. She also used a hormone implant and an echinacea product. One case; no rate. Methods, limits and funding Outcomes: Resolution of galactorrhea after stopping Limitations: One case, a supplement rather than tea. Other products she used cannot be excluded. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Hurseresht 2026 Assessment of Trace and Macro Elements in Medicinal Plants: Implications for Safety and Phytoremediation. Biol Trace Elem Res · PMID 40601286 · DOI	Other plant	42 42 medicinal plant samples from one garden in Hamadan, Iran	Aerial parts of medicinal plants aerial parts Not given here	Urtica dioica had the highest calcium level among the plants and the highest cadmium uptake factor (0.92). The authors say it may be considered for cleaning contaminated soil, and that cadmium had the highest hazard quotient of the trace elements studied. Cadmium uptake factor 0.92 for nettle. Methods, limits and funding Outcomes: Trace elements, including cadmium Limitations: One garden. It says nothing about tea made from commercial leaf. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Jacquet 2009 Phytalgic, a food supplement, vs placebo in patients with osteoarthritis of the knee or hip: a randomised double-blind placebo-controlled clinical trial. Arthritis Res Ther · PMID 20015358 · DOI	Randomized controlled trial	81 81 people with knee or hip osteoarthritis who regularly used painkillers or NSAIDs	Phytalgic: a mixed food supplement of fish oil, vitamin E and Urtica dioica Not given here 3 months · vs Placebo	After 3 months the mix group used fewer painkillers (6.5 vs 16.5 tablets a week) and fewer NSAIDs (0.4 vs 1.0 daily doses), and had lower WOMAC scores than placebo. Painkiller use 6.5 vs 16.5 per week (P < 0.001); NSAID use 0.4 vs 1.0 per day (P = 0.02). (Painkillers: -4.9 to -15.1; NSAIDs: -0.2 to -1.2) Methods, limits and funding Outcomes: Use of NSAIDs and painkillers; WOMAC scores Limitations: A three-ingredient mix. The effect of nettle alone cannot be separated from fish oil and vitamin E. Not a tea. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Registration: NCT00666523 Read: abstract
Kianbakht 2013 Improved glycemic control in patients with advanced type 2 diabetes mellitus taking Urtica dioica leaf extract: a randomized double-blind placebo-controlled clinical trial. Clin Lab · PMID 24273930 · DOI	Randomized controlled trial	92 92 people with type 2 diabetes needing insulin, 46 per group	Nettle leaf extract in capsules, taken with usual diabetes drugs leaf extract (capsule) Not given here 3 months · vs Placebo	Fasting glucose, 2-hour glucose and HbA1c were lower with nettle (P < 0.001, 0.009 and 0.006). Other measures were not different from placebo. Fasting glucose P < 0.001; 2-hour glucose P = 0.009; HbA1c P = 0.006. Methods, limits and funding Outcomes: Fasting and after-meal glucose, HbA1c, creatinine, liver enzymes, blood pressure Limitations: A capsule extract taken on top of diabetes drugs, not a tea. Three months only. Part of a group of similar Iranian trials. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Letsyo 2017 Incidence of Pyrrolizidine Alkaloids in Herbal Medicines from German Retail Markets: Risk Assessments and Implications to Consumers. Phytother Res · PMID 28960556 · DOI	Other	98 98 herbal medicines from German shops and pharmacies	Retail herbal products tested for pyrrolizidine alkaloids various Not given here	About 63% of the 98 products were positive. The authors say that products with St John's wort, artichoke, Urtica dioica and some mixtures were frequently contaminated above the recommended values of the German and European medicines agencies. Alkaloids found in many products, nettle among the frequently affected. Methods, limits and funding Outcomes: Alkaloid amounts Limitations: The abstract does not give the nettle product type (tea or capsule), number or amount. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Mekhfi 2004 Platelet anti-aggregant property of some Moroccan medicinal plants. J Ethnopharmacol · PMID 15325737 · DOI	Laboratory research in vitro	Test-tube platelets	Extract of Urtica dioica (and four other plants) Not given here	All five plant extracts reduced platelet clumping in a dose-dependent way. The nettle extract needed a higher concentration for the same effect than the others. Lab only. Methods, limits and funding Outcomes: Platelet clumping triggered by thrombin and ADP Limitations: Test tube. Not tea. It shows a possible effect only. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Mithril 2012 Safety evaluation of some wild plants in the New Nordic Diet. Food Chem Toxicol · PMID 23009884 · DOI	Other	Four wild plants used as food: stinging nettle, sorrel, chickweed, common lambsquarters	Wild food plants leaf as food Not given here	For most compounds the hazards were minor. The one precaution found was for common lambsquarters because of its presumed high oxalic acid. The authors say better compositional analyses are needed before daily eating of large amounts of wild plants can be called safe. No oxalate precaution was raised for nettle in this evaluation. Methods, limits and funding Outcomes: Bioactive compounds compared with those in common foods Limitations: About nettle as a food, not tea. The abstract gives no oxalate figure for nettle. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Mittman 1990 Randomized, double-blind study of freeze-dried Urtica dioica in the treatment of allergic rhinitis. Planta Med · PMID 2192379 · DOI	Randomized controlled trial	98 98 people with allergic rhinitis; 69 finished	Freeze-dried preparation of Urtica dioica (stinging nettles) Not given here 1 week of treatment, follow-up at one week · vs Placebo	Nettle was rated higher than placebo in the global assessments. In the diary data it was rated only slightly higher. The abstract gives no numbers. Better global rating than placebo; only slightly better in diaries (no figures given). Methods, limits and funding Outcomes: Daily symptom diaries and a global rating at the follow-up visit Limitations: Old trial. 29 of 98 did not finish. The abstract gives no numbers and does not say which plant part was used. A freeze-dried product, not a tea. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Moré 2017 A Rosa canina - Urtica dioica - Harpagophytum procumbens/zeyheri Combination Significantly Reduces Gonarthritis Symptoms in a Randomized, Placebo-Controlled Double-Blind Study. Planta Med · PMID 28614869 · DOI	Randomized controlled trial	92 92 people with knee osteoarthritis (gonarthritis)	MA212: rosehip puree/juice concentrate, nettle leaf extract and devil's claw root extract, plus vitamin D nettle leaf extract in a mixed drink Not given here 12 weeks · vs Placebo	WOMAC pain improved by 29.87 points with the mix and by 10.23 with placebo (significant). Both groups improved. The authors say it was well tolerated. Pain score change 29.87 vs 10.23 (significant in favour of the mix). Methods, limits and funding Outcomes: WOMAC pain score and others Limitations: A three-herb mix, so nettle alone cannot be judged. Placebo group also improved. The abstract does not say who paid for the study. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Ozen 2003 Modulatory effect of Urtica dioica L. (Urticaceae) leaf extract on biotransformation enzyme systems, antioxidant enzymes, lactate dehydrogenase and lipid peroxidation in mice. Phytomedicine · PMID 12834006 · DOI	Animal research animal	Swiss albino mice	80% ethanol leaf extract of Urtica dioica, by mouth leaf extract Not given here 14 days · vs Control	Cytochrome P450 and P450 reductase were lower in the liver of treated mice, while several other enzymes rose. Mice: lower P450 activity. Methods, limits and funding Outcomes: Liver enzymes that break down drugs Limitations: Mouse study with an alcohol extract, not tea. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Randall 2000 Randomized controlled trial of nettle sting for treatment of base-of-thumb pain. J R Soc Med · PMID 10911825 · DOI	Randomized controlled trial	27 27 people with osteoarthritis pain at the base of the thumb or index finger	Stinging nettle leaf (Urtica dioica) applied to the painful area fresh leaf, on the skin Not given here 1 week, then a 5-week washout, then 1 week of the other treatment (crossover) · vs White deadnettle leaf (Lamium album)	After one week, pain and disability scores fell more with nettle sting than with the placebo leaf (P = 0.026 and P = 0.0027). Pain P = 0.026; disability P = 0.0027 (vs placebo leaf). Methods, limits and funding Outcomes: Pain (visual analogue scale) and disability (health assessment questionnaire) Limitations: Very small crossover trial. The leaf was applied to the skin, not drunk. A stinging leaf is hard to blind. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Randall 2008 Nettle sting for chronic knee pain: a randomised controlled pilot study. Complement Ther Med · PMID 18514907 · DOI	Randomized controlled trial	42 42 people aged 55 to 80 with knee pain and likely knee osteoarthritis	Stinging nettle (Urtica dioica) applied to the knee fresh plant, on the skin Not given here 1 week · vs Urtica galeopsifolia (a non-stinging nettle) as a placebo	Pain scores fell by 1.7 points with nettle and by 1.6 points with the placebo plant. The study was a feasibility pilot. Pain change 1.7 vs 1.6 points (no difference). (Nettle 0.6 to 2.9; controls 0.5 to 2.7) Methods, limits and funding Outcomes: WOMAC pain score; whether a larger trial is practical Limitations: A pilot study, not built to show a difference. Applied to the skin, not drunk. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Roschek 2009 Nettle extract (Urtica dioica) affects key receptors and enzymes associated with allergic rhinitis. Phytother Res · PMID 19140159 · DOI	Laboratory research in vitro	Test-tube and enzyme assays	Nettle extract Not given here	In test systems the extract blocked the histamine-1 receptor, mast cell tryptase and several inflammation enzymes. Lab only; the abstract reports concentrations that block each target in the test system. Methods, limits and funding Outcomes: Blocking of histamine-1 receptor, mast cell tryptase, COX-1, COX-2 and HPGDS Limitations: Lab study. It does not show any effect in people. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Safarinejad 2005 Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study. J Herb Pharmacother · PMID 16635963	Randomized controlled trial	620 620 men with urinary symptoms from an enlarged prostate (BPH)	Urtica dioica preparation (the abstract does not name the plant part or extract) Not given here 6 months, then both groups on nettle up to 18 months · vs Placebo	At 6 months 81% of the nettle group reported better symptoms against 16% of the placebo group. IPSS fell from 19.8 to 11.8 with nettle and from 19.2 to 17.7 with placebo (P = 0.002). Peak flow rose by 8.2 mL/s with nettle and 3.4 with placebo. Residual urine fell from 73 to 36 mL. Prostate size went from 40.1 to 36.3 cc. PSA and testosterone did not change. No side effects were found. The author says more trials are needed before concluding it is effective. IPSS 19.8 to 11.8 vs 19.2 to 17.7 (P = 0.002); Qmax +8.2 vs +3.4 mL/s. Methods, limits and funding Outcomes: IPSS symptom score, peak urine flow (Qmax), post-void residual urine, PSA, testosterone, prostate size Limitations: One author. The results are much larger than in the 12-month root trial, which found no flow benefit. The abstract does not name the plant part, so it cannot be linked to leaf or root. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Sahin 2007 Gynaecomastia in a man and hyperoestrogenism in a woman due to ingestion of nettle (Urtica dioica). N Z Med J · PMID 18264183	Case report	2 A man with breast enlargement and a woman with milk discharge, Turkey	Nettle tea leaf (sold as a herbal tea in Turkey) Not given here	The authors report breast enlargement in a man and milk discharge in a woman in whom the only cause they found was nettle tea. Two cases; no rate. Methods, limits and funding Outcomes: Breast changes after nettle tea Limitations: The abstract is brief and does not describe the tests. Two cases cannot show cause. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Sahiti 2023 Bioaccumulation and distribution of Pb, Ni, Zn and Fe in stinging nettle (Urtica dioica) tissues and heavy metal-contamination assessment in the industrial zone of smelter Ferronikeli (Drenas-Kosovo). J Environ Sci Health A · PMID 37463563 · DOI	Other plant	Nettle and soil near a nickel smelter, Kosovo	Nettle plant tissues leaf, stem, root Not given here	The authors found that stinging nettle is not a hyperaccumulator (uptake factor below 1 for all four metals), even where soil metals were above allowed limits. Uptake factor below 1. Methods, limits and funding Outcomes: Metal levels in nettle and soil Limitations: A polluted-site study, not a tea. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Samaha 2019 Antihypertensive Indigenous Lebanese Plants: Ethnopharmacology and a Clinical Trial. Biomolecules · PMID 31330767 · DOI	Randomized controlled trial	29 29 people with mild high blood pressure in four groups (three plants and placebo)	Urtica dioica, Mentha longifolia or Viola odorata plant extract (amount not given here) Not given here 16 weeks · vs Placebo	The abstract reports dose- and duration-related drops in blood pressure for the three plants, nettle among them, and calls them effective, safe and promising. It gives no figures for nettle. Significant drops reported (no figures for nettle in the abstract). Methods, limits and funding Outcomes: Systolic, diastolic and mean arterial blood pressure Limitations: Only 29 people split over four groups, so about seven per group. The abstract does not describe the extract or the funding. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Schneider 2004 [Stinging nettle root extract (Bazoton-uno) in long term treatment of benign prostatic syndrome (BPS). Results of a randomized, double-blind, placebo controlled multicenter study after 12 months]. Urologe A · PMID 15045190 · DOI	Randomized controlled trial	246 246 men with BPH	Nettle ROOT dry extract (Bazoton uno) root Not given here 12 months · vs Placebo	IPSS fell from 18.7 to 13.0 with nettle and from 18.5 to 13.8 with placebo (P = 0.0233). Peak flow and residual urine did not differ significantly from placebo. The authors say a strong rise in peak flow or fall in residual urine is not to be expected. IPSS 18.7 to 13.0 vs 18.5 to 13.8 (P = 0.0233); no difference in Qmax or residual urine. Methods, limits and funding Outcomes: IPSS, peak urine flow (Qmax), residual urine, adverse events Limitations: Root extract, a different product from leaf tea. The abstract does not say who paid. The placebo group improved almost as much. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract (the product is named by its brand). Read: abstract
Schulz 2015 Detection of pyrrolizidine alkaloids in German licensed herbal medicinal teas. Phytomedicine · PMID 26055130 · DOI	Other	169 169 licensed medicinal teas, including 19 nettle teas	Commercial herbal teas tested for 23 pyrrolizidine alkaloids leaf (nettle teas) and others Not given here	Across all 169 teas, 30% of single-ingredient teas and 56.9% of mixtures had alkaloids above the lowest measurable amount. Eleven teas exceeded the recommended intake limit. Single-ingredient teas had much less or none. The abstract does not give results for the nettle teas separately. Nettle result not separated in the abstract. Methods, limits and funding Outcomes: Alkaloid amounts in the dry herb and in prepared infusions Limitations: Germany only; the abstract does not say how the 19 nettle teas did. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Szabo 2006 Analysis of nitrate ion in nettle (Urtica dioica L.) by ion-pair chromatographic method on a C30 stationary phase. J Agric Food Chem · PMID 16756329 · DOI	Other plant	Nettle plant samples (a lab method paper)	Nettle plant material Not given here	The authors focus on nettle because it has an increased ability to accumulate nitrate. The paper is a laboratory method for measuring it. Method paper; no amounts for tea. Methods, limits and funding Outcomes: Nitrate measurement Limitations: It describes a method, not a safety finding for people. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Tabrizi 2022 Effects of Urtica dioica on Metabolic Profiles in Type 2 Diabetes: A Systematic Review and Meta-analysis of Clinical Trials. Mini Rev Med Chem · PMID 34587883 · DOI	Meta-analysis	13 clinical trials in people with type 2 diabetes	Urtica dioica products (the abstract does not separate tea from extracts) Not given here various · vs Control groups	Compared with controls, nettle lowered fasting glucose by 17.17 mg/dl, HbA1c by 0.93, CRP by 1.09 mg/dl, triglycerides by 26.94 mg/dl and systolic blood pressure by 5.03 mmHg. It did not change insulin, total, LDL or HDL cholesterol, BMI or diastolic blood pressure. Heterogeneity was very high for glucose (I2 93.2%). FBG -17.17 mg/dl; HbA1c -0.93; CRP -1.09 mg/dl; TG -26.94 mg/dl; SBP -5.03 mmHg. (FBG -26.60 to -7.73; HbA1c -1.66 to -0.17; CRP -1.64 to -0.53; TG -52.07 to -1.82; SBP -8.15 to -1.91) Methods, limits and funding Outcomes: Fasting glucose, HbA1c, CRP, blood fats, blood pressure Limitations: Trials differed a lot (I2 93.2% for glucose, 90% for triglycerides). Searches ended in December 2019. The abstract does not say how many trials used tea. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Tahri 2000 Acute diuretic, natriuretic and hypotensive effects of a continuous perfusion of aqueous extract of Urtica dioica in the rat. J Ethnopharmacol · PMID 11025144 · DOI	Animal research animal	Anaesthetised male Wistar rats	Aqueous (water) extract of Urtica dioica aerial parts, given into a vein aerial parts Not given here 1.25 hours · vs Furosemide (water pill) as a control	Blood pressure fell by 15% and 38% at the low and high dose. Urine volume rose by 11% and 84%, and sodium loss by 28% and 143%. The high-dose blood pressure effect lasted, which the authors say may be toxic. Rats: urine volume +11% and +84%; blood pressure -15% and -38%. Methods, limits and funding Outcomes: Blood pressure, urine volume, sodium in urine Limitations: Animal study with a drip into a vein, not a drink. It cannot be used to say what tea does in people. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Tiotiu 2016 Urtica dioica pollen allergy: Clinical, biological, and allergomics analysis. Ann Allergy Asthma Immunol · PMID 27788883 · DOI	Case report	2 Two adult men with nasal allergy to nettle pollen and/or leaves	Exposure to nettle pollen pollen Not given here	Allergic rhinitis was due to Urtica dioica pollen in both men. Four allergen proteins were found. The authors call nettle pollen poorly allergenic in general. Two cases. Methods, limits and funding Outcomes: Allergy tests; nettle pollen allergens Limitations: Pollen, not tea. It shows allergy to the plant is possible but uncommon. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Uslu 2011 Urticaria due to Urtica dioica in a neonate. Eur J Pediatr · PMID 20953796 · DOI	Case report	1 A 17-day-old infant with hives	Water boiled with stinging nettle put on the mother's nipples applied to skin Not given here 2 days	The mother used nettle water on cracked nipples twice a day for 2 days. The infant developed generalized hives and had high total and nettle-specific IgE and a positive skin prick test to the nettle water. The rash cleared by the second day without treatment. One case. Methods, limits and funding Outcomes: Hives in the infant; allergy tests Limitations: One case of skin use, not drinking. It shows allergy is possible. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Wilt 2000 Phytotherapy for benign prostatic hyperplasia. Public Health Nutr · PMID 11276294 · DOI	Meta-analysis	44 studies of six plant products for BPH	Plant preparations for BPH, including Urtica dioica various (nettle studies: mainly root) Not given here at least 30 days · vs Placebo or other BPH drugs	The review says studies of Urtica dioica are limited and that nettle may work when combined with saw palmetto or Pygeum. It concludes there is no convincing evidence supporting Urtica dioica alone for BPH. Saw palmetto had the strongest evidence. No convincing evidence for nettle alone (2000). Methods, limits and funding Outcomes: Urinary symptoms and flow Limitations: Old (searches to 1997). Many studies did not report results in a way that could be pooled. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
Ziaei 2020 The effect of nettle (Urtica dioica) supplementation on the glycemic control of patients with type 2 diabetes mellitus: A systematic review and meta-analysis. Phytother Res · PMID 31802554 · DOI	Meta-analysis	401 Eight randomized trials, 401 adults with type 2 diabetes	Nettle supplements Not given here various · vs Control groups	Fasting blood sugar fell by 18.01 mg/dl. Insulin, the insulin resistance index and HbA1c did not fall significantly. Five trials were rated good quality, one fair and two poor. Heterogeneity was very high (I2 94.6%). FBS -18.01 mg/dl; HbA1c -0.77% (not significant). (FBS -30.04 to -5.97; HbA1c -1.77 to 0.22) Methods, limits and funding Outcomes: Fasting blood sugar, insulin, insulin resistance index, HbA1c Limitations: Very high heterogeneity. The authors say more studies are needed. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract
n/a 2010 Assessment report on Urtica dioica L., Urtica urens L., folium (EMA/HMPC/508013/2007) European Medicines Agency (HMPC) · Source	Authoritative guidance n/a	n/a	n/a	The assessor says clinical studies in joint pain are not enough for a well-established use, but support the plausibility of traditional use. The traditional use for minor urinary complaints is called plausible because of long use and the data for the whole herb. The report concludes nettle leaf preparations are well tolerated. Methods, limits and funding Outcomes: Assessor's conclusions Limitations: The assessor's own overall view; the report summarizes studies of many kinds, including tests on cells and animals. Read: full-text
n/a 2010 Community herbal monograph on Urtica dioica L.; Urtica urens L., folium (nettle leaf) (EMA/HMPC/508015/2007), final, 14 January 2010 European Medicines Agency (HMPC) · Source	Authoritative guidance n/a	n/a	n/a	The EU herbal committee lists cut dried nettle leaf as a herbal tea and as extracts. It accepts two traditional uses, based only on long use: relief of minor joint pain, and increasing the amount of urine to flush the urinary tract as an aid in minor urinary complaints. It says use should not go beyond 4 weeks for joint pain and 2 to 4 weeks for the urinary use, and that a doctor should be seen if symptoms persist. Methods, limits and funding Outcomes: Accepted uses, limits and warnings Limitations: A traditional-use record. It is based on long use, not on trials. Read: full-text
n/a 2021 Nettle (About Herbs), Memorial Sloan Kettering Cancer Center, last updated 7 December 2021 Memorial Sloan Kettering Cancer Center · Source	Authoritative guidance n/a	n/a	n/a	MSK lists, as reported adverse reactions, gynecomastia in a man and galactorrhea in a woman with nettle tea, urticaria in a breastfed infant after the mother used nettle water, allergic rhinitis from nettle pollen, and a severe reaction to a different Australian nettle tree. It lists possible interactions with CYP450 drugs (animal data), diuretics (additive effect in theory) and blood-pressure medicines (animal data), and says clinical relevance of each has yet to be determined. Methods, limits and funding Outcomes: See results Limitations: A cancer-centre herb summary page. It cites the same case reports we read; clinical relevance is stated as unknown. Read: full-text
n/a 2023 Stinging Nettle (LiverTox: Clinical and Research Information on Drug-Induced Liver Injury) LiverTox, NIDDK · PMID 37011125	Authoritative guidance n/a	n/a	n/a	LiverTox says stinging nettle extracts of leaf or root are generally well tolerated and have not been implicated in serum enzyme rises or clinically apparent liver injury. Methods, limits and funding Outcomes: See results Limitations: Read as the PubMed record's abstract; the full book page could not be opened (the NCBI site asked for a human check). Covers extracts, not tea specifically. Read: abstract
n/a 2026 Stinging Nettle (Drugs and Lactation Database, LactMed) LactMed, NICHD · PMID 30000836	Authoritative guidance n/a	n/a	n/a	LactMed says nettle has been used by nursing mothers as a tonic and as a milk-boosting herb, with only minimal scientific support for the latter. It notes that applying nettle to a mother's nipple led to an allergic skin rash in her breastfed infant, and says it is probably best not to apply stinging nettle to the breast while breastfeeding. It does not give a safe-or-unsafe verdict for drinking the tea. Methods, limits and funding Outcomes: See results Limitations: Read as the PubMed record's abstract (record dated 15 October 2026); the full book page could not be opened (the NCBI site asked for a human check). Read: abstract
n/a 2026 PubChem compound records for compounds named in the EMA assessment report n/a · Source	Database record n/a	n/a	n/a	PubChem name searches on 2026-10-25 returned: quercetin CID 5280343 (C15H10O7), rutin 5280805 (C27H30O16), kaempferol 5280863 (C15H10O6), isorhamnetin 5281654 (C16H12O7), scopoletin 5280460 (C10H8O4), beta-sitosterol 222284 (C29H50O), caffeoylmalic acid 6124299 (C13H12O8), nicotine 89594 (C10H14N2). Methods, limits and funding Outcomes: Compound identifiers Limitations: Identifiers only; they say nothing about amounts in tea. Read: database
n/a 2026 GBIF Backbone Taxonomy: Urtica dioica L. (species match, accepted) n/a · Source	Database record n/a	n/a	n/a	GBIF lists Urtica dioica L. as ACCEPTED (key 7960979), family Urticaceae, order Rosales, class Magnoliopsida, phylum Tracheophyta. Retrieved 2026-10-25 through the GBIF species-match API. Methods, limits and funding Outcomes: Accepted name and classification Limitations: Taxonomy only. Read: database
n/a 2026 GBIF Backbone Taxonomy: Urtica urens L. (species match, accepted) n/a · Source	Database record n/a	n/a	n/a	GBIF lists Urtica urens L. as ACCEPTED (key 5361815), family Urticaceae. Retrieved 2026-10-25 through the GBIF species-match API. Methods, limits and funding Outcomes: Accepted name Limitations: Taxonomy only. Read: database
n/a 2026 NCBI Taxonomy: Urtica dioica (taxid 3501) and Urtica urens (taxid 473050) n/a · Source	Database record n/a	n/a	n/a	NCBI Taxonomy lists Urtica dioica as a species (taxid 3501, common name great nettle, eudicots). A search for Urtica urens returned taxid 473050; only the first record was opened. Retrieved 2026-10-25 through the NCBI E-utilities. Methods, limits and funding Outcomes: Species record Limitations: Only the Urtica dioica record was opened in full. Read: database

What we do not know yet

What the evidence supports: low at best, and mostly for products that are not the tea.
No trial of nettle leaf tea for any health outcome in the sources we read.
No human trial measuring urine output from nettle tea.
No study of nettle tea with water pills, blood pressure, blood thinner or lithium medicines.
No measured caffeine or oxalate content for nettle tea.
The EMA's newer monograph for the aerial parts (herba) and the full LiverTox and LactMed book pages were not read.

How new research is added

New studies are found by a saved PubMed search and placed in a review queue. A person reads each one before it changes any rating or safety wording.

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".

Metabolic 3

▼

Fasting blood glucose

Lowered in trials

Blood sugar measured after an overnight fast.

Low certainty

Results and what it means

Why it was measured

The main measure of blood sugar control.

Statistical vs. clinical meaning

Consistent direction, very high heterogeneity.

Safety implication

Possible low blood sugar with diabetes medicines; not reported in the abstracts.

Study	Result	People	Product
²⁸	-17.17 mg/dl across 13 trials.	People with type 2 diabetes	Nettle products
³³	-18.01 mg/dl across 8 trials.	401 adults with type 2 diabetes	Nettle supplements

^{28 33 11}

↕

HbA1c

Mixed results in trials

A blood test that shows average blood sugar over about three months.

Low certainty

Results and what it means

Why it was measured

Used to judge long-term blood sugar control.

Statistical vs. clinical meaning

Reviews disagree on whether the drop is significant.

Safety implication

See fasting glucose.

Study	Result	People	Product
²⁸	-0.93 (significant).	People with type 2 diabetes	Nettle products
³³	-0.77%, not significant.	401 adults with type 2 diabetes	Nettle supplements
¹¹	Lower than placebo (P = 0.006).	92 people on insulin	Leaf extract capsules

^{28 33 11}

▼

Triglycerides

Lowered in trials

A type of fat in the blood.

Very low certainty

Results and what it means

Why it was measured

Raised levels are linked to heart disease risk.

Statistical vs. clinical meaning

Wide interval and high heterogeneity.

Safety implication

None noted.

Study	Result	People	Product
²⁸	-26.94 mg/dl (95% CI -52.07 to -1.82).	People with type 2 diabetes	Nettle products
²	Lower than control after 8 weeks.	50 women with type 2 diabetes	Alcohol-water extract

^{28 2}

Inflammatory 1

▼

C-reactive protein (CRP)

Lowered in trials

A blood marker that rises with inflammation.

Very low certainty

Results and what it means

Why it was measured

A general measure of inflammation.

Statistical vs. clinical meaning

A lab marker only.

Safety implication

None noted.

Study	Result	People	Product
²⁸	-1.09 mg/dl (95% CI -1.64 to -0.53).	People with type 2 diabetes	Nettle products

²⁸

Other 5

▼

International Prostate Symptom Score (IPSS)

Lowered in trials

A questionnaire score of urinary symptoms; lower is better.

Low certainty

Results and what it means

Why it was measured

It is the standard way trials measure prostate-related urinary symptoms.

Statistical vs. clinical meaning

Small gains over placebo; placebo groups also improved.

Safety implication

None noted in the abstracts.

Study	Result	People	Product
²¹	19.8 to 11.8 with nettle vs 19.2 to 17.7 with placebo at 6 months.	620 men with BPH	Urtica dioica preparation
²⁵	18.7 to 13.0 with nettle root extract vs 18.5 to 13.8 with placebo at 12 months.	246 men with BPH	Nettle root extract

^{21 25 1}

↕

Peak urine flow (Qmax)

Mixed results in trials

The fastest rate of urine flow, in mL per second.

Low certainty

Results and what it means

Why it was measured

A measure of how freely urine passes.

Statistical vs. clinical meaning

The two trials disagree.

Safety implication

None noted in the abstracts.

Study	Result	People	Product
²¹	Rose 8.2 mL/s with nettle and 3.4 with placebo.	620 men with BPH	Urtica dioica preparation
²⁵	Rose 3.0 mL/s with nettle and 2.9 with placebo (not a significant difference).	246 men with BPH	Nettle root extract

^{21 25}

▼

Eosinophils in nasal smear

Lowered in trials

A type of white blood cell counted in nasal mucus; more suggests allergy.

Very low certainty

Results and what it means

Why it was measured

A lab marker of allergic inflammation in the nose.

Statistical vs. clinical meaning

A lab marker; symptom scores improved with placebo too.

Safety implication

None noted in the abstract.

Study	Result	People	Product
³	Lower after treatment with nettle root extract (P < .01).	74 people with allergic rhinitis, 40 finished	Nettle root extract tablets

↕

Joint pain score (WOMAC pain and visual pain scales)

Mixed results in trials

Questionnaire or scale scores of joint pain; lower is better.

Very low certainty

Results and what it means

Why it was measured

The way osteoarthritis trials judge pain.

Statistical vs. clinical meaning

One small trial positive, one pilot no difference.

Safety implication

The sting was a minor irritation.

Study	Result	People	Product
¹⁸	Pain score fell more with nettle sting than with placebo leaf (P = 0.026).	27 people with thumb osteoarthritis	Nettle leaf on the skin
¹⁹	Pain fell 1.7 with nettle and 1.6 with placebo.	42 people with knee pain	Nettle on the skin

^{18 19}

▼

Systolic blood pressure

Lowered in trials

The top number of a blood pressure reading.

Very low certainty

Results and what it means

Why it was measured

A main risk factor measure for heart disease and stroke.

Statistical vs. clinical meaning

One pooled result from diabetic patients.

Safety implication

Add-on effect with blood pressure medicines is unstudied.

Study	Result	People	Product
²⁸	-5.03 mmHg (95% CI -8.15 to -1.91).	People with type 2 diabetes	Nettle products

²⁸

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 5

Pregnancy and breastfeeding: not recommended. The EU herbal committee says safety in pregnancy and breastfeeding has not been established and, for lack of data, use is not recommended. LactMed says nettle has been used by nursing mothers but with only minimal scientific support, and one baby developed hives after the mother used nettle water on her nipples. If you are pregnant or breastfeeding, ask your doctor, midwife or pharmacist before drinking nettle tea. Authoritative guidance ^{35 38 31}
Water pills, blood pressure, diabetes and blood thinner medicines. The EU monograph says no interactions have been reported, which means none were reported, not that none exist. Even so, nettle leaf is a traditional water-increasing herb, and the EMA assessment report quotes a warning that long use of any diuretic can upset body salts and minerals. Memorial Sloan Kettering lists possible added effects with diuretics and blood pressure medicines, based on theory and animal data. Pooled trials show nettle products lower blood sugar in people with type 2 diabetes, so low blood sugar is possible in theory with diabetes medicines. The EMA notes that nettle leaf contains some vitamin K, which German labels use as a reason to warn about warfarin-type medicines; the EMA assessor calculated the amount as very small and kept the wording "none reported". Ask your pharmacist if you take any of these medicines. Authoritative guidance ^{35 34 36 28 33}
People told to limit fluids: heart or kidney disease. The EU monograph lists as a contraindication any condition where less fluid is recommended, for example severe heart or kidney disease. This is about fluid, because the leaf is used to increase urine. A food safety review of wild plants, including nettle, raised an oxalic acid precaution for common lambsquarters but not for nettle; it was about nettle as a food and gives no oxalate figure for nettle. If you have kidney stones or kidney disease, ask your doctor. Authoritative guidance ^{35 14}
Allergy and skin reactions. The EU monograph lists allergy to the plant as a contraindication, and says itching, rash and hives can occur, frequency unknown. Case reports describe hives in a newborn after nettle water was put on the mother's nipples, and hay fever from nettle pollen in two men. Stop and ask a doctor if a rash or swelling appears. Authoritative guidance ^{35 31 30}
Children and teenagers under 12. The EU monograph says use under age 12 is not recommended because there are not enough data. Ask a doctor before giving nettle tea to a child. Authoritative guidance ³⁵

Side effects 4

Effect	How often	Severity and recovery	Evidence
Mild stomach and bowel upset (nausea, vomiting, diarrhoea) Listed in the EU monograph with unknown frequency.	Not known	Mild Not described	Authoritative guidance ³⁵
Skin reactions: itching, rash, hives One case was from skin use in a newborn.	Not known	Mild to moderate Hives cleared in about two days in one infant	Authoritative guidance ^{35 31}
Breast enlargement in a man and milk discharge in women Three people in two papers; the tea report is brief, and the supplement case also involved a hormone implant. Cause is not proven.	Rare case reports	Not described; the woman recovered in a week after stopping a nettle supplement Milk discharge resolved one week after stopping in the supplement case	Case report ^{22 8 36}
Hay fever or other nasal allergy from nettle pollen Two men. This is about pollen exposure, not tea.	Rare	Not described Not described	Case report ³⁰

Liver

LiverTox says stinging nettle extracts (leaf or root) are generally well tolerated and have not been linked to liver enzyme rises or clinically apparent liver injury. A small mouse study and one small diabetes trial reported better, not worse, liver enzyme results; neither is a safety study. ³⁷

How often. No cases found in LiverTox.

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

Medicines and supplements 7

With	Why it matters	Importance	Evidence	What to do
Diuretics (water pills such as furosemide and hydrochlorothiazide) and other water-increasing herbs drug	Nettle leaf is a traditional water-increasing herb. In anaesthetised rats a water extract given into a vein raised urine and sodium loss. Memorial Sloan Kettering says an added effect is possible in theory; the EMA assessment report quotes a warning that long use of any diuretic can cause salt and mineral imbalance.	Unknown in people. The EMA monograph says no interactions reported.	Animal research Very low certainty ^{29 36 34 35}	Ask your pharmacist or doctor before combining.
Blood pressure medicines drug	Animal data show nettle extract lowers blood pressure, and a pooled analysis in diabetic patients showed a small drop in the top number. Memorial Sloan Kettering says nettle may add to blood pressure medicines; clinical relevance not yet known.	Unknown. Do not change blood pressure medicine because of nettle.	Animal research Very low certainty ^{29 28 36}	Ask your doctor or pharmacist.
Diabetes medicines (insulin, tablets) and other blood-sugar-lowering herbs drug	Pooled trials show lower fasting blood sugar with nettle products in people with type 2 diabetes. The EMA assessment report quotes a handbook warning that heavy use may affect treatment of diabetes and high blood pressure, and the EMA reporter adds that no data support that statement.	Possible added effect; not measured as a drug interaction.	Meta-analysis Low certainty ^{28 33 34}	Tell your doctor or pharmacist if you drink nettle tea regularly and check your blood sugar plan.
Warfarin and similar vitamin K blockers (such as phenprocoumon) drug	The EMA assessment report says nettle leaf contains vitamin K and could in theory weaken warfarin-type medicines; German labelling carries this warning. Using the vitamin K content in the literature, the assessor calculated that nettle at the maximum daily amount would provide less than 1 percent of an effective vitamin K dose, and no clinical interactions have been reported.	Theoretical. No case report found in the sources we read.	Pharmacological theory Not enough evidence ^{34 35}	If you take warfarin, tell your clinic before drinking nettle tea regularly so any change can be watched.
Antiplatelet medicines and other blood thinners (aspirin, clopidogrel and others) drug	In test tubes, nettle extract reduced platelet clumping triggered by thrombin and ADP, with a weaker effect than four other plants tested. Not shown in people.	Unknown.	Laboratory research Not enough evidence ¹³	Ask a pharmacist if you take blood thinners.
Lithium drug	No source we read mentions lithium and nettle. This is our reasoning, not a finding: lithium levels depend on body salt and water, and nettle is a traditional water-increasing herb, so a change is conceivable. Nothing has been reported.	Unknown. No report found.	Pharmacological theory Not enough evidence ³⁴	If you take lithium, ask your prescriber before drinking nettle tea regularly.
Medicines broken down by liver enzymes (CYP450) drug	In mice a leaf extract lowered liver P450 enzymes. Memorial Sloan Kettering says animal studies suggest this and that the clinical relevance is not known.	Unknown.	Animal research Not enough evidence ^{17 36}	Ask a pharmacist if your medicine has a narrow safety margin.

Who should check first 5

Situation	Advice	Evidence
Allergy to nettle	Do not use. The EU lists hypersensitivity as a contraindication.	Authoritative guidance ³⁵
Any condition where less fluid is recommended (for example severe heart or kidney disease)	The EU lists this as a contraindication. Ask your doctor.	Authoritative guidance ³⁵
Pregnancy and breastfeeding	The EU says use is not recommended for lack of data. Ask your doctor, midwife or pharmacist.	Authoritative guidance ^{35 38}
Children under 12	The EU says use is not recommended for lack of data. Ask a doctor.	Authoritative guidance ³⁵
Joint pain with swelling, redness or fever, or urinary symptoms with fever, pain on passing urine, spasm or blood in the urine	The EU says see a doctor. These need a diagnosis, not a tea.	Authoritative guidance ³⁵

Overdose, product quality and regulators

Summary. The EU monograph says no case of overdose has been reported, and that tests of reproductive toxicity, genotoxicity and carcinogenicity have not been performed. In rats, the highest dose of an extract given into a vein produced a lasting blood pressure drop that the authors say may be toxic. Nettle tea is not given into a vein, so this does not show tea is toxic.

Animal. Rat study (extract into a vein): possible toxic effect at the higher dose.

Human doses studied. Trials used extracts and capsules; amounts are not given here.

High dose or long term signals. The EU limits use to a few weeks for its traditional indications. No long-term safety study of the tea was found in the sources we read.

Overdose response. No case reported (EMA).

Genotoxicity. Not tested (EMA).

Toxic or hazardous parts. The fresh plant stings; the stinging hairs contain small amounts of acetylcholine, serotonin and formic acid, according to the EMA assessment report.

Herbal tea quality varies. For nettle, the papers we read describe four things: natural plant alkaloids, nitrate, heavy metals and wild-collection risks.

Pyrrolizidine alkaloids. A German study of 169 licensed medicinal teas, including 19 nettle teas, found alkaloids above the lowest measurable amount in 30% of single-ingredient products and 56.9% of mixtures. The abstract does not give nettle results separately. A second German study of 98 herbal products said that St John's wort, artichoke, Urtica dioica and mixed products were frequently above recommended values. The papers say these alkaloids can be toxic to the liver, can damage genes and can cause cancer. ^{26 12}

Nitrate. A lab method paper says nettle has an increased ability to accumulate nitrate. A study of eight wild plants found boiling lowered nitrate in all but asparagus. The abstracts give no nitrate amounts for nettle tea. ^{27 4}

Heavy metals. In Polish samples, common nettle had the highest median mercury of five herbs, and 32% of all samples were over the EU limit, mostly self-collected. In an Iranian garden, nettle took up cadmium the most among 42 plants. Near a nickel smelter in Kosovo nettle was not a hyperaccumulator. ^{5 9 23}

Wild collection. The Polish mercury paper says that self-collecting nettle may carry a mercury risk. No paper we read compares shop tea with wild leaf for other contaminants. ⁵

Body	Action	Date
European Medicines Agency (HMPC) (European Union)	Community herbal monograph on nettle leaf (Urtica dioica, Urtica urens). Accepts traditional use for minor joint pain and for increasing urine as an aid in minor urinary complaints, on long use only. Contraindicated in allergy and conditions with reduced fluid intake. Not recommended in pregnancy, breastfeeding or under 12. No interactions reported. Not for use beyond 4 weeks (joint pain) or 2 to 4 weeks (urinary use). source	2010-01-14
European Medicines Agency (HMPC), assessment report (European Union)	Assessor's conclusions: nettle leaf preparations are well tolerated; clinical trials are not enough for well-established use but support plausibility of the traditional uses. Notes the vitamin K warning on German labels and judges the amount small. source	2010
LiverTox (NIDDK) (United States)	Stinging nettle extracts generally well tolerated; no clinically apparent liver injury linked. source	2023-03-03
LactMed (NICHD) (United States)	Nettle used as a postpartum tonic and milk-boosting herb with only minimal scientific support; allergic rash in a breastfed infant after the mother put nettle on her nipple; probably best not to apply it to the breast. source	2026-10-15
Memorial Sloan Kettering Cancer Center (United States)	Lists adverse reactions from case reports and possible interactions (CYP450, diuretics, blood pressure medicines) with clinical relevance not determined. source	2021-12-07

When to get medical help

Swelling of the lips, tongue or face, wheezing, trouble breathing or hives after nettle: get emergency help now (call your local emergency number).
Fever, pain on passing urine, spasm or blood in the urine while using nettle for urinary complaints: see a doctor.
Joint pain with swelling, redness or fever: see a doctor.
Very frequent urination with dizziness, weakness or muscle cramps, or signs of low blood sugar such as shaking, sweating and confusion if you have diabetes: get medical help.

Stop using the product 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

Is nettle tea caffeine-free?

Nettle is not a true tea from the tea plant. No source we read lists caffeine as a constituent of nettle leaf, and the EMA report names caffeic acid esters (a different compound) and traces of nicotine. We did not find a direct caffeine measurement for nettle tea, so this rests on the published constituent list.

³⁴

Does nettle tea work as a water pill?

Nettle leaf is a traditional water-increasing herb, and the EU accepts it for flushing the urinary tract in minor complaints on long use only. No human trial of the tea measured urine output. In rats, an extract given into a vein raised urine. The EU says not to use it if you have been told to limit fluids.

^{35 29}

Does nettle tea help with hay fever?

Not shown. Two small trials exist, and neither used tea. A freeze-dried nettle product was rated a little better than placebo in 1990. In a 2017 trial of nettle root tablets, the placebo helped symptoms as much as nettle.

^{15 3}

Does nettle tea help with arthritis or joint pain?

The EU accepts nettle leaf for minor joint pain on traditional use only. Trials used nettle sting on the skin or mixed products, not tea. The evidence is very low quality or cannot separate nettle from other ingredients.

^{18 19 6 10 16 35}

Is nettle tea good for the prostate?

The prostate research is on nettle root extract, which is a different product from leaf tea. Root trials show modest symptom score gains, and a review found no convincing evidence for nettle alone. See a doctor for urinary symptoms.

^{21 25 1 32}

Does nettle tea lower blood sugar or blood pressure?

Pooled trials in people with type 2 diabetes found lower fasting blood sugar and a small drop in the top blood pressure number with nettle products. Those products were mostly extracts or capsules, not tea. If you take diabetes or blood pressure medicine, ask your doctor or pharmacist before drinking nettle tea regularly.

^{28 33 11}

Is nettle tea safe in pregnancy or while breastfeeding?

The EU herbal committee says safety has not been established and use is not recommended. LactMed says there is only minimal scientific support for nettle as a milk-boosting herb. Ask your doctor, midwife or pharmacist.

^{35 38}

Can I give nettle tea to children?

The EU says use under age 12 is not recommended for lack of data. Ask a doctor.

³⁵

Does nettle tea interact with medicines?

The EU monograph says none reported, which is not the same as none exist. Possible added effects are described in theory or animals for water pills and blood pressure medicines. Nettle leaf contains some vitamin K, which German labels use to warn about warfarin-type medicines, although the EMA assessor judged the amount small. No source we read mentions lithium. Ask your pharmacist.

^{35 34 36}

Can nettle tea affect the liver or kidneys?

LiverTox says nettle extracts have not been linked to liver injury. The EU lists conditions where less fluid is advised, such as severe heart or kidney disease, as a contraindication. A food-safety review of wild plants raised an oxalic acid precaution for common lambsquarters, but not for nettle; it gives no oxalate figure for nettle.

^{37 35 14}

What is the difference between nettle tea, nettle extract and nettle root?

Tea is the dried leaf steeped in water. Extracts are concentrated products made with water or alcohol, and most blood sugar trials used them. Root extract is a separate product studied for the prostate. Results for one do not carry over to the others.

^{35 11 25}

Is nettle tea contaminated with anything?

Some herbal teas carry natural plant alkaloids. A German study of 169 medicinal teas, 19 of them nettle, found them in many products, and another study said Urtica dioica products were often above recommended values. Nettle also accumulates nitrate and, in some samples, mercury or cadmium. Wild-picked leaf was the main source of high mercury in a Polish study.

^{26 12 5 9 27}

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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 read PubMed abstracts of 33 papers, the PubMed records for LiverTox and LactMed, and the EMA monograph, EMA assessment report and Memorial Sloan Kettering page in full. We checked the plant name in GBIF and NCBI Taxonomy and compounds in PubChem. Certainty ratings are the compiler's own reading. Funding is not stated in most abstracts. No study is cited that we could not verify.
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.

Sources 42

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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Amiri Behzadi A, Kalalian-Moghaddam H, Ahmadi AH. Effects of Urtica dioica supplementation on blood lipids, hepatic enzymes and nitric oxide levels in type 2 diabetic patients: A double blind, randomized clinical trial.. Avicenna J Phytomed. 2016. PMID 28078249. (abstract)
Bakhshaee M, Mohammad Pour AH, Esmaeili M et al. Efficacy of Supportive Therapy of Allergic Rhinitis by Stinging Nettle (Urtica dioica) root extract: a Randomized, Double-Blind, Placebo- Controlled, Clinical Trial.. Iran J Pharm Res. 2017. PMID 29844782. (abstract)
Boari F, Cefola M, Di Gioia F et al. Effect of cooking methods on antioxidant activity and nitrate content of selected wild Mediterranean plants.. Int J Food Sci Nutr. 2013. PMID 23701122. DOI 10.3109/09637486.2013.799125. (abstract)
Brodziak-Dopierała B, Fischer A. Analysis of Mercury Content in Medicinal Plants Popular in Poland.. Molecules. 2026. PMID 42883333. DOI 10.3390/molecules31193569. (abstract)
Cameron M, Chrubasik S. Topical herbal therapies for treating osteoarthritis.. Cochrane Database Syst Rev. 2013. PMID 23728701. DOI 10.1002/14651858.CD010538. (abstract)
Chrubasik JE, Roufogalis BD, Wagner H et al. A comprehensive review on nettle effect and efficacy profiles, Part I: herba urticae.. Phytomedicine. 2007. PMID 17493795. DOI 10.1016/j.phymed.2007.03.004. (abstract)
Easton L, Vaid S, Nagel AK et al. Stinging Nettle (Urtica dioica): An Unusual Case of Galactorrhea.. Am J Case Rep. 2021. PMID 34876549. DOI 10.12659/AJCR.933999. (abstract)
Hurseresht Z, Jalali M. Assessment of Trace and Macro Elements in Medicinal Plants: Implications for Safety and Phytoremediation.. Biol Trace Elem Res. 2026. PMID 40601286. DOI 10.1007/s12011-025-04714-x. (abstract)
Jacquet A, Girodet PO, Pariente A et al. Phytalgic, a food supplement, vs placebo in patients with osteoarthritis of the knee or hip: a randomised double-blind placebo-controlled clinical trial.. Arthritis Res Ther. 2009. PMID 20015358. DOI 10.1186/ar2891. (abstract)
Kianbakht S, Khalighi-Sigaroodi F, Dabaghian FH. Improved glycemic control in patients with advanced type 2 diabetes mellitus taking Urtica dioica leaf extract: a randomized double-blind placebo-controlled clinical trial.. Clin Lab. 2013. PMID 24273930. DOI 10.7754/clin.lab.2012.121019. (abstract)
Letsyo E, Jerz G, Winterhalter P et al. Incidence of Pyrrolizidine Alkaloids in Herbal Medicines from German Retail Markets: Risk Assessments and Implications to Consumers.. Phytother Res. 2017. PMID 28960556. DOI 10.1002/ptr.5935. (abstract)
Mekhfi H, El Haouari M, Legssyer A et al. Platelet anti-aggregant property of some Moroccan medicinal plants.. J Ethnopharmacol. 2004. PMID 15325737. DOI 10.1016/j.jep.2004.06.005. (abstract)
Mithril C, Dragsted LO. Safety evaluation of some wild plants in the New Nordic Diet.. Food Chem Toxicol. 2012. PMID 23009884. DOI 10.1016/j.fct.2012.09.016. (abstract)
Mittman P. Randomized, double-blind study of freeze-dried Urtica dioica in the treatment of allergic rhinitis.. Planta Med. 1990. PMID 2192379. DOI 10.1055/s-2006-960881. (abstract)
Moré M, Gruenwald J, Pohl U et al. A Rosa canina - Urtica dioica - Harpagophytum procumbens/zeyheri Combination Significantly Reduces Gonarthritis Symptoms in a Randomized, Placebo-Controlled Double-Blind Study.. Planta Med. 2017. PMID 28614869. DOI 10.1055/s-0043-112750. (abstract)
Ozen T, Korkmaz H. Modulatory effect of Urtica dioica L. (Urticaceae) leaf extract on biotransformation enzyme systems, antioxidant enzymes, lactate dehydrogenase and lipid peroxidation in mice.. Phytomedicine. 2003. PMID 12834006. DOI 10.1078/0944-7113-00275. (abstract)
Randall C, Randall H, Dobbs F et al. Randomized controlled trial of nettle sting for treatment of base-of-thumb pain.. J R Soc Med. 2000. PMID 10911825. DOI 10.1177/014107680009300607. (abstract)
Randall C, Dickens A, White A et al. Nettle sting for chronic knee pain: a randomised controlled pilot study.. Complement Ther Med. 2008. PMID 18514907. DOI 10.1016/j.ctim.2007.01.012. (abstract)
Roschek B, Fink RC, McMichael M et al. Nettle extract (Urtica dioica) affects key receptors and enzymes associated with allergic rhinitis.. Phytother Res. 2009. PMID 19140159. DOI 10.1002/ptr.2763. (abstract)
Safarinejad MR. Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study.. J Herb Pharmacother. 2005. PMID 16635963. (abstract)
Sahin M, Yilmaz H, Gursoy A et al. Gynaecomastia in a man and hyperoestrogenism in a woman due to ingestion of nettle (Urtica dioica).. N Z Med J. 2007. PMID 18264183. (abstract)
Sahiti H, Bislimi K, Abdurrahmani Gagica N et al. Bioaccumulation and distribution of Pb, Ni, Zn and Fe in stinging nettle (Urtica dioica) tissues and heavy metal-contamination assessment in the industrial zone of smelter Ferronikeli (Drenas-Kosovo).. J Environ Sci Health A. 2023. PMID 37463563. DOI 10.1080/10934529.2023.2236535. (abstract)
Samaha AA, Fawaz M, Salami A et al. Antihypertensive Indigenous Lebanese Plants: Ethnopharmacology and a Clinical Trial.. Biomolecules. 2019. PMID 31330767. DOI 10.3390/biom9070292. (abstract)
Schneider T, Rübben H. [Stinging nettle root extract (Bazoton-uno) in long term treatment of benign prostatic syndrome (BPS). Results of a randomized, double-blind, placebo controlled multicenter study after 12 months].. Urologe A. 2004. PMID 15045190. DOI 10.1007/s00120-004-0532-7. (abstract)
Schulz M, Meins J, Diemert S et al. Detection of pyrrolizidine alkaloids in German licensed herbal medicinal teas.. Phytomedicine. 2015. PMID 26055130. DOI 10.1016/j.phymed.2015.03.020. (abstract)
Szabo Z, Böddi K, Mark L et al. Analysis of nitrate ion in nettle (Urtica dioica L.) by ion-pair chromatographic method on a C30 stationary phase.. J Agric Food Chem. 2006. PMID 16756329. DOI 10.1021/jf0524628. (abstract)
Tabrizi R, Sekhavati E, Nowrouzi-Sohrabi P et al. Effects of Urtica dioica on Metabolic Profiles in Type 2 Diabetes: A Systematic Review and Meta-analysis of Clinical Trials.. Mini Rev Med Chem. 2022. PMID 34587883. DOI 10.2174/1389557521666210929143112. (abstract)
Tahri A, Yamani S, Legssyer A et al. Acute diuretic, natriuretic and hypotensive effects of a continuous perfusion of aqueous extract of Urtica dioica in the rat.. J Ethnopharmacol. 2000. PMID 11025144. DOI 10.1016/s0378-8741(00)00270-1. (abstract)
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Ziaei R, Foshati S, Hadi A et al. The effect of nettle (Urtica dioica) supplementation on the glycemic control of patients with type 2 diabetes mellitus: A systematic review and meta-analysis.. Phytother Res. 2020. PMID 31802554. DOI 10.1002/ptr.6535. (abstract)
n/a. Assessment report on Urtica dioica L., Urtica urens L., folium (EMA/HMPC/508013/2007). European Medicines Agency (HMPC). 2010. (full-text)
n/a. Community herbal monograph on Urtica dioica L.; Urtica urens L., folium (nettle leaf) (EMA/HMPC/508015/2007), final, 14 January 2010. European Medicines Agency (HMPC). 2010. (full-text)
n/a. Nettle (About Herbs), Memorial Sloan Kettering Cancer Center, last updated 7 December 2021. Memorial Sloan Kettering Cancer Center. 2021. (full-text)
n/a. Stinging Nettle (LiverTox: Clinical and Research Information on Drug-Induced Liver Injury). LiverTox, NIDDK. 2023. PMID 37011125. (abstract)
n/a. Stinging Nettle (Drugs and Lactation Database, LactMed). LactMed, NICHD. 2026. PMID 30000836. (abstract)
n/a. PubChem compound records for compounds named in the EMA assessment report. n/a. 2026. (database)
n/a. GBIF Backbone Taxonomy: Urtica dioica L. (species match, accepted). n/a. 2026. (database)
n/a. GBIF Backbone Taxonomy: Urtica urens L. (species match, accepted). n/a. 2026. (database)
n/a. NCBI Taxonomy: Urtica dioica (taxid 3501) and Urtica urens (taxid 473050). n/a. 2026. (database)

Where to buy

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

The herb is the first or only ingredient
Organic or lab-tested if that matters to you
Loose leaf or tea bags, and how long they have been stored
If you take medicines or are pregnant, ask a pharmacist about the herb first

Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.

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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.