Green tea extract and EGCG

Q: What is green tea extract?

It is a concentrated supplement made from the leaves of the tea plant, Camellia sinensis. Its main catechin is EGCG. It is sold as capsules and tablets, with or without caffeine.

Q: Is green tea extract the same as drinking green tea?

No. NCCIH reports no safety concerns for green tea as a drink in adults (caffeine aside), while liver injury has been reported mainly with extract tablets and capsules. A capsule can carry much more EGCG than a cup. Brewed tea has its own page.

Q: Does green tea extract help you lose weight?

Not in a way that matters. A Cochrane review found a small loss that was not statistically significant and unlikely to be useful in practice.

Q: Does it lower cholesterol?

A little. Reviews of randomised trials found LDL cholesterol about 4.6 mg/dL lower on average, with no change in HDL. It is a small lab effect and does not show fewer heart attacks.

Q: Does it lower blood pressure?

A little, by about 2 mmHg in a review of 13 trials. NCCIH also lists raised blood pressure as an extract side effect, so results are mixed.

Q: Does green tea extract prevent cancer?

Not shown. A 2020 Cochrane review of 142 studies found inconsistent results and only limited evidence for any benefit.

Q: Can green tea extract harm the liver?

Yes, rarely. NCCIH says liver injury is uncommon but has been reported, mainly with extract tablets and capsules. EFSA found raised liver enzymes in trials at 800 mg or more EGCG a day as a supplement. Stop and get help if you have yellow skin or eyes, dark urine or belly pain.

Q: Who should be extra careful?

People with a liver problem, people who take the medicines listed in the Safety tab, and anyone sensitive to caffeine. USP's label caution says not to use extract with a liver problem. NCCIH says people with a particular immune-gene variant seem more prone to liver injury.

Q: Does it interact with medicines?

Yes, some. NCCIH names nadolol, atorvastatin and raloxifene, and a small trial found fexofenadine exposure fell by 70%. Ask a pharmacist.

Q: Is it safe in pregnancy or for children?

The sources read cover only caffeine, which NCCIH says should be kept to moderate levels in pregnancy. No source read gives safety data on extracts or EGCG for pregnancy or children. Ask a doctor or pharmacist.

Camellia sinensis (L.) Kuntze extract; epigallocatechin gallate (EGCG) · also called Green tea extract, GTE, green tea catechins, EGCG

Green tea extract is a concentrated supplement made from the leaves of the tea plant. Its main active catechin is EGCG. Trials show small drops in LDL cholesterol and blood pressure and little real weight loss. Rare liver injury has been reported, mostly with capsules and tablets rather than brewed tea. Ask a doctor or pharmacist first, especially if you have liver problems or take medicines.

General information, not medical advice. Last substantive update October 26, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

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About Green tea extract and EGCG

Green tea extract is a concentrated supplement, not the same thing as a cup of tea. Trials show small effects on cholesterol and blood pressure and little real weight loss. The main concern is rare liver injury, mostly with capsules and tablets.

What green tea extract and EGCG are

Green, black and oolong teas all come from the same plant, Camellia sinensis. Green tea leaves are steamed or pan-fried and dried but not fermented (NCCIH). Most of the polyphenols in green tea are catechins, and EGCG is the main one (EFSA).

Extracts concentrate these catechins into capsules and tablets. Some are decaffeinated. Tea has been used for health for about 3,000 years, but the capsule is a modern product. Brewed tea has its own page, linked below.

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Tea in a cup versus extract in a capsule

EFSA estimates that EU adults get about 90 to 300 mg of EGCG a day from green tea infusions on average, and up to 866 mg a day if they drink a lot. Food supplements give a much wider range, from 5 to 1,000 mg a day.

NCCIH reports no safety concerns for green tea as a drink in adults, apart from the caffeine. A systematic review found liver adverse events with concentrated, catechin-rich preparations taken as large bolus doses, but not with brewed tea or extracts used in drinks or foods. EFSA adds that rare liver injury has been reported after infusions too, probably an unpredictable reaction in a few people. These are findings, not advice about how much to take.

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What the research shows

The best-supported effect is a small fall in LDL and total cholesterol across several reviews (moderate certainty by our rating). Blood pressure falls about 2 mmHg in some reviews, but extracts are also listed as raising blood pressure, so we rate this low. A 2012 Cochrane review found no clinically useful weight loss.

Evidence for preventing cancer is inconsistent and limited. A few small trials in fatty liver found lower liver enzymes, but the evidence is very thin. No trial in these reviews measured heart attacks, strokes or cancer cases as a result of the extract.

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The liver warning

NCCIH says liver injury is uncommon but has been reported in people using green tea products, mainly extract tablets and capsules. The US Pharmacopeia reviewed case reports and saw injury of the liver cells at EGCG intakes from about 140 to about 1,000 mg a day, with big differences between people. EFSA found that trials of 800 mg or more EGCG a day as a supplement raised liver enzymes.

A review of 34 trials found liver events were rare (7 people on extract and 1 on control) and mostly mild, but it could not rule out a small extra risk. USP asks that extract labels tell people not to take it on an empty stomach and not to use it with a liver problem, and to stop and see a practitioner if signs of liver trouble appear. These are regulator statements and trial findings, not advice to take any amount.

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Medicines and green tea extract

NCCIH says high amounts of green tea lower blood levels of the beta-blocker nadolol, that extract can lower levels of the statin atorvastatin, and that raloxifene also interacts. In a small crossover trial of 10 healthy people, a green tea extract drink cut exposure to the antihistamine fexofenadine by 70%. A 2023 review adds effects on other statins, verapamil and beta-blockers. In the lab, green tea catechins block the cancer drug bortezomib.

Tell a doctor or pharmacist about any extract you use, especially if you take any of these medicines.

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A prescription ointment is a different thing

The FDA has approved a prescription ointment made from a specific green tea extract for warts on the outside of the genitals and around the anus (NCCIH). It is a skin medicine used under medical care, and it does not show anything about capsules you swallow.

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At a glance

Traditional uses history, not proof

Tea has been drunk for health for about 3,000 years (NCCIH)
Extracts are sold as supplements for weight, cholesterol and general health

Studied for research

Cholesterol (total and LDL), moderate certainty (small effect)
Blood pressure, low certainty (small effect)
Body weight, low certainty (little or no clinically useful loss)
Fatty liver markers, very low certainty
Cancer prevention, insufficient evidence
Antioxidant activity in the lab, not shown in people

Main compounds

Epigallocatechin gallate (EGCG)
Other tea catechins
Caffeine (removed in decaffeinated extracts)

Common forms

Capsules and tablets of green tea extract
Decaffeinated extract
Purified EGCG
Brewed green tea or matcha (the drink, covered on its own page)
Prescription ointment for genital warts (a drug, not a supplement)

Research links: 2020 USP review: liver harm from green tea extracts · 2018 EFSA opinion on the safety of green tea catechins · 2016 review of 34 trials: liver safety of extracts · 2012 Cochrane review: green tea for weight loss · 2020 Cochrane review: green tea and cancer prevention · NCCIH: Green Tea, usefulness and safety · Research Library · Genes & Biomarkers Library

What it is and its history

Accepted scientific name: Green tea extract and EGCG (an extract of Camellia sinensis leaf and its main catechin, epigallocatechin-3-gallate)
Naming authority: Camellia sinensis (L.) Kuntze (accepted species name per GBIF; the same name appears in the EFSA opinion)
Common names: Green tea extract (English); GTE (English (abbreviation)); Green tea catechins (English); EGCG (English (abbreviation)); Extracto de té verde (Spanish); Catequinas del té verde (Spanish)
Family or group: Theaceae (tea family); the leaves give green, black and oolong tea.
Classification: Plantae > Tracheophyta > Ericales > Theaceae > Camellia > Camellia sinensis
Native range: Not researched. NCCIH says the tea plant was first cultivated in China thousands of years ago.
Habitat: Not researched.
What it looks like: Roots: Not researched.; Stems: Not researched.; Leaves: Leaves are the part used; for green tea they are steamed or pan-fried and dried, not fermented (NCCIH).; Flowers: Not researched.; Fruit: Not researched.
Cultivation: Not researched.
Harvest and processing: Green tea leaves are steamed, pan fried and dried but not fermented; black tea is fermented and oolong is partly fermented (NCCIH).
Look-alikes and adulterants: Name: Brewed green tea, matcha; Note: The drink; it has its own page. The extract is a concentrated supplement and is not equivalent.; Name: Black tea and oolong tea; Note: Same plant, different processing (NCCIH).; Name: Green tea extract ointment; Note: A prescription skin product, FDA-approved for external genital and perianal warts (NCCIH); not a supplement.
Sustainability and conservation: Not assessed.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
		NCCIH (NIH), Green Tea page, read 2026-10-26

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
Epigallocatechin gallate (EGCG) PubChem 65064	catechin (polyphenol)	Leaf Varies a lot with how the extract is made (USP). EU adults get about 90 to 300 mg a day from green tea infusions on average and supplements give 5 to 1,000 mg a day (EFSA).	The main catechin of green tea; the compound linked to liver-enzyme rises in trials at high supplement amounts and the one studied in drug-interaction work. ^{1 10 9}	Human data
Other catechins	catechin (polyphenol)	Leaf Not read from a source.	Most of the polyphenols in green tea are catechins (EFSA); individual catechins were not looked up. ¹	Human data
Caffeine PubChem 2519	methylxanthine	Leaf Not read from a source.	Present in green tea (NCCIH); removed in decaffeinated extracts. Believed to add to the effect of catechins on energy use (Cochrane weight review). ^{15 6}	Human data

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Liver first-pass clearance	Not specified in the abstract	USP says repeated bolus doses of extract on an empty stomach raise blood EGCG a lot, possibly because first-pass elimination is saturated. ¹⁰	Human data
Drug transport in the gut	OATP1A2	EGCG blocked OATP1A2-mediated uptake of fexofenadine in lab cells, and in 10 volunteers the extract cut fexofenadine exposure by 70%. ⁹	Human and in vitro
Direct binding to a cancer drug	Catechol group of catechins binds the boronic acid group of bortezomib	The review describes formation of stable cyclic boronate esters that abolish the drug's anticancer activity in the lab. ¹¹	Laboratory research
Antioxidant activity	Not specified	Catechins are polyphenol antioxidants in laboratory tests. This is not shown to protect people (see the cancer review). ²	Laboratory research

Absorption, metabolism and elimination

Absorption: USP: bolus doses of extract during fasting greatly raise blood EGCG compared with other ways of taking it, possibly by saturating first-pass elimination.
Distribution: Not read.
Metabolism: Not read.
Elimination: Not read.
Bioavailability: Higher when extract is taken as a bolus on an empty stomach (USP). Hu and colleagues linked internal catechin dose to liver risk.

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Isolated compounds versus whole extracts

A cup of brewed tea and a concentrated extract capsule are not the same thing. Reviews find liver events with concentrated, catechin-rich preparations taken as large doses, but not with brewed tea or extracts in drinks or food. NCCIH reports no safety concerns for green tea as a drink in adults (caffeine aside). Still, EFSA notes rare liver injury has been reported after infusions too. Most cholesterol trials tested extract, and the drink has its own page.

Nutritional composition

Green tea is not an essential nutrient. Catechin amounts in tea are estimates from EFSA exposure data; USDA catechin values were not read.

8benefits and uses looked at

15studies and sources checked

Moderate certaintybest evidence rating found

4lab markers tracked in trials

2 moderate certainty2 low certainty1 very low certainty3 not enough evidence

What was looked at

The 8 benefits and uses checked for Green tea extract and EGCG, each with how strong the evidence is. Tap one to open it.

Body weight and waist sizeLow certainty
Cholesterol (total and LDL)Moderate certainty
Blood pressureLow certainty
Cancer preventionNot enough evidence
Fatty liver disease (NAFLD)Very low certainty
Antioxidant activity in the labNot enough evidence
Genital warts (prescription ointment, not a supplement)Not enough evidence
Where catechins come from: tea versus extractModerate certainty

Lab markers tracked in the studies

LDL cholesterolSystolic blood pressureBody weightALT (alanine aminotransferase)

What is Green tea extract and EGCG good for?

The main studied uses and how strong the human evidence is for each. Most trials mix tea drinks and extract capsules, and effects are small.

Cholesterol (total and LDL)Moderate certaintyAcross 31 trials, green tea lowered total and LDL cholesterol by about 4.6 mg/dL, with no change in HDL. The effect is small and is a lab number, not fewer heart attacks. Blood pressureLow certaintyThirteen trials found blood pressure about 2 mmHg lower on average. NCCIH also lists raised blood pressure as an extract side effect, so the picture is mixed. Body weight and waist sizeLow certaintyA Cochrane review found a small weight loss that was not statistically significant and is unlikely to matter in practice. Trials outside Japan found almost no difference. Cancer preventionNot enough evidenceA Cochrane review of 142 studies found inconsistent results and only limited evidence for any benefit. No link to cancer deaths was found. Fatty liver disease (liver enzymes)Very low certaintyFour small trials found lower ALT and AST with green tea in people with fatty liver. The evidence is very thin, and extracts are also linked to rare liver injury. Antioxidant activity in the labNot enough evidenceCatechins neutralise free radicals in lab tests. This does not show that capsules prevent disease or slow ageing in people. Where catechins come from: tea versus extractModerate certaintyEFSA estimates EU adults get about 90 to 300 mg of EGCG a day from tea infusions and that supplements give 5 to 1,000 mg a day. A capsule can carry far more EGCG than a cup.

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.

Body weight and waist size

Low certainty

A 2012 Cochrane review of green tea preparations in overweight or obese adults found a small weight loss that was not statistically significant and is unlikely to matter in practice. Trials outside Japan found essentially no difference; Japanese trials, which could not be pooled, ranged from almost nothing to a few kilograms. NCCIH says the effect on body weight is modest at most.

2 studiesGreen tea drinks, powders and extracts were all included; the abstrac…

Studies, doses and limits

What the trials found

The Cochrane review pooled six trials outside Japan (532 people): weight changed by -0.04 kg (95% CI -0.5 to 0.4), BMI by -0.2 kg/m2 and waist by -0.2 cm, none significant. Eight Japanese trials (1,030 people) ranged from -0.2 to -3.5 kg and could not be pooled. Two trials on keeping weight off (184 people) showed no significant effect. NCCIH says catechins and caffeine may have a modest effect and that results depend on the product and on how active people are.

Results

Little to no meaningful weight loss. Results differed between Japan and other countries, so a small effect in some groups cannot be ruled out.

Effect sizes as reported

Weight MD -0.04 kg (-0.5 to 0.4), six non-Japanese trials; Japanese trials -0.2 to -3.5 kg (not pooled).

Why this rating

Low: the authors call the loss small, not significant and unlikely to be clinically important; trials were only 12 to 13 weeks and differ a lot. The review is from 2012.

Form and dose studied

Green tea drinks, powders and extracts were all included; the abstract does not separate them.

Who was studied

Overweight or obese adults; trials mostly outside Japan gave the null results.

Limits

Short trials, mixed products, older review. Newer trials (for example a 2024 review of tea catechins plus exercise) were found by title only and were not read.

Why researchers looked

Green tea extracts and catechins are sold for weight control, so trials compared them with placebo or no tea.

Traditional use

Green tea has been drunk for health for about 3,000 years (NCCIH). A concentrated extract in capsules is a modern supplement, and results for the drink do not automatically apply to the extract.

Proposed mechanism Preliminary mechanism

Catechins and caffeine are believed to raise energy use. This was not shown to cause weight loss in the review.

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

Liver injury is rare but has been reported with concentrated extracts; see the Safety tab. Two trials reported hospital care for an event judged unrelated.

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Cholesterol (total and LDL)

Moderate certainty

Reviews of randomised trials find a small drop in total and LDL cholesterol with green tea, with no change in HDL cholesterol and no clear change in triglycerides. NCCIH notes most of the cholesterol trials tested extract supplements rather than tea as a drink. These are lab numbers, not fewer heart attacks.

4 studiesTea drinks and extracts were pooled together; the extract trials are …

Studies, doses and limits

What the trials found

A 2020 meta-analysis of 31 trials (3,321 adults) found total cholesterol 4.66 mg/dL lower and LDL 4.55 mg/dL lower, with HDL unchanged and triglycerides not significantly changed. A 2014 meta-analysis of 13 trials found LDL 0.16 mmol/L lower. The 2013 Cochrane review (green tea trials only) found LDL 0.64 mmol/L lower but said results were not stable when single trials were left out. NCCIH says the reduction is small and does not affect HDL or triglycerides.

Results

A small fall in LDL cholesterol, shown in several reviews. No trial in these reviews measured heart attacks or strokes.

Effect sizes as reported

LDL -4.55 mg/dL (-6.31 to -2.80), 31 trials; LDL -0.16 mmol/L (-0.22 to -0.09), 13 trials; Cochrane green tea LDL -0.64 mmol/L (-0.77 to -0.52).

Why this rating

Moderate (our rating, the reviewers did not grade it): the direction is the same across three reviews and NCCIH, but the size is small and the Cochrane result was not stable.

Form and dose studied

Tea drinks and extracts were pooled together; the extract trials are the ones that raise liver questions.

Who was studied

Adults with normal or raised weight and cholesterol.

Limits

Small average change; products and amounts differ; no clinical-event data.

Why researchers looked

Many people with raised cholesterol try green tea products, so trials measured blood fats.

Traditional use

Green tea has been drunk for health for about 3,000 years (NCCIH). A concentrated extract in capsules is a modern supplement, and results for the drink do not automatically apply to the extract.

Proposed mechanism Not established

How catechins might lower cholesterol was not established in the sources read.

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

Liver injury is rare but has been reported with concentrated extracts; see the Safety tab.

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Blood pressure

Low certainty

Trial reviews find that green tea lowers blood pressure by a small amount, about 2 mmHg on average, with larger falls in people who start with higher pressure. NCCIH lists raised blood pressure among side effects of extracts, so the picture is mixed.

4 studiesDrinks and extracts were pooled; bigger effects were seen in extract …

Studies, doses and limits

What the trials found

A 2014 meta-analysis of 13 trials found systolic pressure 2.08 mmHg lower and diastolic 1.71 mmHg lower, with bigger falls in people whose starting systolic pressure was 130 or higher and in studies using extract. The 2013 Cochrane review found falls of 3.18 and 3.42 mmHg for green tea but said results were not stable. NCCIH lists increased blood pressure among the side effects of extract supplements, and a Cochrane cancer review also reported raised blood pressure in some extract trials.

Results

A small lowering of blood pressure in trials, but an increase is also reported as a side effect of extracts, so results are mixed.

Effect sizes as reported

Systolic -2.08 mmHg (-3.06 to -1.05); diastolic -1.71 mmHg (-2.86 to -0.56), 13 trials.

Why this rating

Low: effects are small and unstable, extracts are also reported to raise blood pressure, and no trial measured strokes or heart attacks.

Form and dose studied

Drinks and extracts were pooled; bigger effects were seen in extract trials.

Who was studied

Adults, more effect in those with starting systolic pressure of 130 mmHg or higher.

Limits

Small effects, mixed products, and a conflicting side-effect report.

Why researchers looked

Green tea is often said to help the heart and blood vessels, so trials measured blood pressure.

Traditional use

Green tea has been drunk for health for about 3,000 years (NCCIH). A concentrated extract in capsules is a modern supplement, and results for the drink do not automatically apply to the extract.

Proposed mechanism Not established

Catechins may relax blood vessels, but this was not shown in the sources read.

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

People on blood pressure medicines should read the Safety tab (nadolol).

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Cancer prevention

Not enough evidence

A 2020 Cochrane review of 142 studies found inconsistent results and only limited evidence that green tea lowers the risk of cancer overall or at any one site. Extract trials were small. Cancer deaths were not linked to green tea intake. NCCIH also says the overall results are inconsistent.

2 studiesMostly green tea as a drink in observational studies; extract in the …

Studies, doses and limits

What the trials found

The review included 11 trials (1,795 people given extract or placebo) and 131 observational studies (over 1,100,000 people). In the trials, the risk of prostate cancer was 0.50 times that of placebo but the range was wide (0.18 to 1.36, low certainty). In observational studies, highest versus lowest green tea intake gave a risk of 0.83 for any cancer (0.65 to 1.07, low certainty) and no link to cancer death (0.99, 0.91 to 1.07). For some cancers, cohort and case-control studies disagreed. Most studies were in Asia.

Results

Inconsistent and not proven. Do not read this as a way to prevent or treat cancer.

Effect sizes as reported

All cancer, highest vs lowest intake: RR 0.83 (0.65 to 1.07); cancer death RR 0.99 (0.91 to 1.07); prostate (trials) RR 0.50 (0.18 to 1.36).

Why this rating

Insufficient: the review's own certainty is low, effects are not statistically significant, and observational studies cannot prove cause.

Form and dose studied

Mostly green tea as a drink in observational studies; extract in the 11 trials.

Who was studied

Mostly Asian populations with high tea intake.

Limits

Confounding in observational studies, small trials, results not generalisable to other populations.

Why researchers looked

Lab studies suggested catechins might slow cancer cells, so researchers looked at tea drinkers and at extract trials.

Traditional use

Green tea has been drunk for health for about 3,000 years (NCCIH). A concentrated extract in capsules is a modern supplement, and results for the drink do not automatically apply to the extract.

Proposed mechanism Lab only

Catechins slow some cancer cells in the lab; this has not been shown to protect people.

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

The same review recorded stomach and gut problems, raised liver enzymes, insomnia, raised blood pressure and skin reactions with extracts.

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Fatty liver disease (NAFLD)

Very low certainty

A 2018 meta-analysis of four small trials in people with non-alcoholic fatty liver disease found lower liver-enzyme levels (ALT, AST) with green tea. The evidence is very thin, and the same extracts are the ones linked to rare liver injury, so this finding does not say extracts are safe for a diseased liver.

2 studiesGreen tea supplements; the abstract does not give the form.

Studies, doses and limits

What the trials found

Four studies in people with fatty liver: ALT fell by 12.81 U/L (95% CI -18.17 to -7.45) and AST by 10.91 U/L (-19.66 to -2.17); BMI, triglycerides, total cholesterol and LDL were also lower, while HDL and the insulin-resistance score did not change significantly. The abstract does not describe the products or the trial quality.

Results

Possible lowering of liver enzymes in a handful of small trials. Not a treatment for fatty liver.

Effect sizes as reported

ALT -12.81 U/L (-18.17 to -7.45); AST -10.91 U/L (-19.66 to -2.17), four studies.

Why this rating

Very low: only four studies, unknown product details and quality, and lab markers rather than liver outcomes.

Form and dose studied

Green tea supplements; the abstract does not give the form.

Who was studied

People with non-alcoholic fatty liver disease.

Limits

Very small evidence base. The title's phrase 'safe alternative' goes beyond the data, because liver injury has been reported with extracts.

Why researchers looked

People with fatty liver look for natural options, so a few small trials tested green tea.

Traditional use

Green tea has been drunk for health for about 3,000 years (NCCIH). A concentrated extract in capsules is a modern supplement, and results for the drink do not automatically apply to the extract.

Proposed mechanism Not established

Not established in the sources read.

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

Anyone with a liver problem should not use extracts without a doctor's advice (see the Safety tab).

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Antioxidant activity in the lab

Not enough evidence

Green tea catechins, especially EGCG, mop up free radicals in laboratory tests. That does not show that capsules prevent disease or slow ageing in people. The Cochrane cancer review found only limited evidence for benefit in people.

2 studiesNot applicable.

Studies, doses and limits

What the trials found

No human trial in the sources read shows that taking green tea extract lowers oxidative damage or prevents disease. See the cancer and heart sections for what trials found.

Results

A lab finding only. It does not translate into a proven health benefit.

Effect sizes as reported

No effect sizes apply.

Why this rating

Insufficient: lab activity only; the human trials read measure other outcomes with mixed results.

Limits

Lab results often fail to carry over to people.

Why researchers looked

The word 'antioxidant' is used to sell green tea products, so it is worth saying what it does and does not mean.

Traditional use

Green tea has been drunk for health for about 3,000 years (NCCIH). A concentrated extract in capsules is a modern supplement, and results for the drink do not automatically apply to the extract.

Proposed mechanism Lab only

Catechins neutralise free radicals in test tubes and cells.

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

Not applicable.

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Genital warts (prescription ointment, not a supplement)

Not enough evidence

The FDA has approved a prescription ointment made from a specific green tea extract for warts on the outside of the genitals and around the anus. It is a skin medicine made and dosed as a drug. It says nothing about green tea capsules.

1 studiesPrescription ointment, applied to the skin only.

Studies, doses and limits

What the trials found

NCCIH states the FDA approval. No trial of the ointment was read for this page, so no results or numbers are given.

Results

An approved prescription use of a particular extract applied to the skin. It is not evidence for swallowing extract capsules.

Effect sizes as reported

No numbers read.

Why this rating

Insufficient on this page: the approval is stated by NCCIH, but no trial data were read.

Form and dose studied

Prescription ointment, applied to the skin only.

Who was studied

Adults with external genital or perianal warts, under medical care.

Limits

Approval statement only; trial results not read.

Why researchers looked

Green tea is sometimes confused with this approved prescription product.

Traditional use

Green tea has been drunk for health for about 3,000 years (NCCIH). A concentrated extract in capsules is a modern supplement, and results for the drink do not automatically apply to the extract.

Proposed mechanism Not covered

Not covered here.

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

Use only as prescribed by a doctor.

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Where catechins come from: tea versus extract

Moderate certainty

Most of the polyphenols in green tea leaf are catechins, and EGCG is the main one. EFSA estimates that adults in the EU get about 90 to 300 mg of EGCG a day from green tea infusions on average, and up to 866 mg a day if they drink a lot. Food supplements give a wide range, from 5 to 1,000 mg of EGCG a day. This is the key difference between tea and capsules: a capsule can deliver far more EGCG in one go.

3 studiesGreen tea infusion versus supplements.

Studies, doses and limits

What the trials found

EFSA states these exposure ranges for the EU adult population. Hu and colleagues found liver adverse events with concentrated catechin-rich preparations taken as large bolus doses, but not with brewed tea or extracts in beverages or food. NCCIH says no safety concerns have been reported for green tea as a drink in adults, apart from caffeine. USDA values for catechins in tea were not read.

Results

Brewed tea and extract capsules are not equivalent. The capsule can carry a much larger load of EGCG.

Effect sizes as reported

EGCG from infusions: 90 to 300 mg a day on average; 866 mg a day in high consumers; supplements 5 to 1,000 mg a day (EFSA, EU adults).

Why this rating

Moderate: the ranges come from an EU regulator's exposure estimates, not from a measured portion table.

Form and dose studied

Green tea infusion versus supplements.

Who was studied

EU adults (EFSA).

Limits

Intake estimates vary by country and tea type. These are not recommended amounts.

Why researchers looked

People want to know how much of the active material a cup of tea gives compared with a capsule.

Traditional use

Green tea has been drunk for health for about 3,000 years (NCCIH). A concentrated extract in capsules is a modern supplement, and results for the drink do not automatically apply to the extract.

Proposed mechanism Nutrient database

Not applicable: this is a content fact.

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

Rare liver injury has been reported after both tea and extract; see the Safety tab.

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Connections to the rest of health

How Green tea extract and EGCG 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	Evidence status	Context	Studies
Weight Management	Low certainty	Body weight and waist size: A 2012 Cochrane review of green tea preparations in overweight or obese adults found a small weight loss that was not statistically significant and is unlikely to matter in practice. Trials outside Japan found essentially no difference; Japanese trials, which could not be pooled, ranged from almost nothing to a few kilograms. NCCIH says the effect on body weight is modest at most.	^{6 15}
Cholesterol Balance	Moderate certainty	Cholesterol (total and LDL): Reviews of randomised trials find a small drop in total and LDL cholesterol with green tea, with no change in HDL cholesterol and no clear change in triglycerides. NCCIH notes most of the cholesterol trials tested extract supplements rather than tea as a drink. These are lab numbers, not fewer heart attacks.	^{13 7 3 15}
Heart Health	Moderate certainty	Cholesterol (total and LDL): Reviews of randomised trials find a small drop in total and LDL cholesterol with green tea, with no change in HDL cholesterol and no clear change in triglycerides. NCCIH notes most of the cholesterol trials tested extract supplements rather than tea as a drink. These are lab numbers, not fewer heart attacks. Blood pressure: Trial reviews find that green tea lowers blood pressure by a small amount, about 2 mmHg on average, with larger falls in people who start with higher pressure. NCCIH lists raised blood pressure among side effects of extracts, so the picture is mixed.	^{13 7 3 15 2}
Blood Pressure Support	Low certainty	Blood pressure: Trial reviews find that green tea lowers blood pressure by a small amount, about 2 mmHg on average, with larger falls in people who start with higher pressure. NCCIH lists raised blood pressure among side effects of extracts, so the picture is mixed.	^{7 3 15 2}
Cellular Protection	Not enough evidence	Cancer prevention: A 2020 Cochrane review of 142 studies found inconsistent results and only limited evidence that green tea lowers the risk of cancer overall or at any one site. Extract trials were small. Cancer deaths were not linked to green tea intake. NCCIH also says the overall results are inconsistent.	^{2 15}
Liver Support	Very low certainty	Fatty liver disease (NAFLD): A 2018 meta-analysis of four small trials in people with non-alcoholic fatty liver disease found lower liver-enzyme levels (ALT, AST) with green tea. The evidence is very thin, and the same extracts are the ones linked to rare liver injury, so this finding does not say extracts are safe for a diseased liver.	^{8 10}
Cellular Protection	Not enough evidence	Antioxidant activity in the lab: Green tea catechins, especially EGCG, mop up free radicals in laboratory tests. That does not show that capsules prevent disease or slow ageing in people. The Cochrane cancer review found only limited evidence for benefit in people.	^{2 15}

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Metabolism Weight	Biological association	Low certainty	Studied for: Body weight and waist size	^{6 15}
Cardiovascular System	Biological association	Moderate certainty	Studied for: Cholesterol (total and LDL) Studied for: Blood pressure	^{13 7 3 15 2}
Whole Body	Biological association	Not enough evidence	Studied for: Cancer prevention Studied for: Antioxidant activity in the lab	^{2 15 1 4}
Liver Detox	Biological association	Very low certainty	Studied for: Fatty liver disease (NAFLD)	^{8 10}
Integumentary System	Biological association	Not enough evidence	Studied for: Genital warts (prescription ointment, not a supplement)	¹⁵

C. Body parts and organs

Connected to	Kind of connection	Evidence status	Context	Studies
Liver	Adverse effect or risk	Documented risk	EFSA found raised transaminases in trials at 800 mg or more EGCG a day as a supplement. Trials found raised liver enzymes at 800 mg or more EGCG a day as a supplement. Preparation or compound: EGCG as a supplement	^{1 10}

E. Health conditions

Connected to	Kind of connection	Evidence status	Context	Studies
Drug-induced liver disease		Documented risk	Rare liver injury has been reported, mostly with concentrated extracts. Rare liver injury has been reported with concentrated green tea extracts. Preparation or compound: Green tea extract capsules and tablets	^{15 10 1 5}

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
ALT	Adverse effect or risk	Clinical trial evidence	Liver enzymes rose in trials at high supplement amounts; they fell in a few small fatty-liver trials. Preparation or compound: EGCG as a supplement	^{1 8}
LDL cholesterol		Clinical trial evidence	A small average fall in LDL cholesterol in trial reviews. Preparation or compound: Green tea (mostly extract)	^{13 7}
LDL cholesterol	Biological association	Moderate certainty	Measured in trials: slightly lower. A lab change is not the same as a health benefit.	^{13 7 3}
Systolic blood pressure	Biological association	Low certainty	Measured in trials: slightly lower. A lab change is not the same as a health benefit.	^{7 3 15}
Body weight	Biological association	Low certainty	Measured in trials: little or no change. A lab change is not the same as a health benefit.	⁶
ALT (alanine aminotransferase)	Biological association	Very low certainty	Measured in trials: lower in fatty-liver trials; higher at 800 mg EGCG a day or more in safety trials. A lab change is not the same as a health benefit.	^{8 1}

J. Genes, receptors and enzymes

Connected to	Kind of connection	Evidence status	Context	Studies
An immune-function gene variant (not named on the NCCIH page)	Preliminary mechanism	Human	NCCIH says people with a specific variant that plays an important role in immune function appear especially susceptible to liver injury; 5 to 15 percent of Americans have it.	¹⁵

K. Biological pathways

Connected to	Kind of connection	Evidence status	Context	Studies
OATP1A2	Preliminary mechanism	In vitro and human	Blocked by EGCG in lab cells; linked to lower fexofenadine absorption.	⁹

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Epigallocatechin gallate (EGCG)	Biological association	Human	The main catechin of green tea; the compound linked to liver-enzyme rises in trials at high supplement amounts and the one studied in drug-interaction work. Preparation or compound: Leaf	^{1 10 9}
Other catechins	Biological association	Human	Most of the polyphenols in green tea are catechins (EFSA); individual catechins were not looked up. Preparation or compound: Leaf	¹
Caffeine	Biological association	Human	Present in green tea (NCCIH); removed in decaffeinated extracts. Believed to add to the effect of catechins on energy use (Cochrane weight review). Preparation or compound: Leaf	^{15 6}

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 26, 2026).

Evidence at a glance: what the research found for 8 outcomes

2Moderate certainty

2Low certainty

1Very low certainty

3Not enough evidence

Each outcome below is one thing researchers measured. Certainty is how far the evidence can be trusted, not how well it works. The full studies are on the next tab.

Body weight and waist size 2 studies Low certainty Cholesterol (total and LDL) 4 studies Moderate certainty Blood pressure 4 studies Low certainty Cancer prevention 2 studies Not enough evidence Fatty liver disease (NAFLD) 2 studies Very low certainty Antioxidant activity in the lab 2 studies Not enough evidence Genital warts (prescription ointment, not a supplement) 1 study Not enough evidence Where catechins come from: tea versus extract 3 studies Moderate certainty

The evidence

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

Evidence by outcome

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 started from our existing green tea extract summary, read the NCCIH page, and re-read PubMed abstracts for reviews, a regulator opinion, a crossover trial and case-report reviews. Only abstracts were read for studies. The NIH LiverTox page was blocked and is marked unread.

Study library: every study we checked 15

Design Research type Year from Search

Study	Design	People	Product, dose, length	Result
EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) 2018 Scientific opinion on the safety of green tea catechins. EFSA J · PMID 32625874 · DOI	Regulatory opinion	Adult population of the EU; interventional studies, monographs, authority reports and a public call for data	Green tea infusions and food supplements containing green tea catechins Leaf Infusions give about 90 to 300 mg EGCG a day on average (high consumers up to 866 mg); supplements give 5 to 1,000 mg EGCG a day	Catechins from traditionally prepared green tea infusions are in general considered safe at reported European intakes, although rare liver injury has been reported after infusions, most probably an idiosyncratic reaction. Interventional trials show that 800 mg or more EGCG a day as a food supplement raises serum transaminases compared with control. Transaminase rise at 800 mg EGCG a day or more as a supplement (trial finding) (Not applicable) Methods, limits and funding Outcomes: Liver toxicity (hepatotoxicity) and serum transaminases Limitations: A safety opinion based on published literature and submitted data. Read from the abstract only; the full opinion's detail was not read. Funding and conflicts: Independent EU risk-assessment panel; no industry funding stated. Read: abstract
Filippini 2020 Green tea (Camellia sinensis) for the prevention of cancer. Cochrane Database Syst Rev · PMID 32118296 · DOI	Systematic review meta analysis	142 studies: 11 randomised trials (1,795 people given green tea extract or placebo) and 131 observational studies (over 1,100,000 people), mostly in Asian populations	Green tea extract (trials) and green tea drinking (observational studies) Leaf Varied Varied · vs Placebo (trials); lowest intake group (observational)	Results were inconsistent, giving limited evidence for a benefit on overall cancer risk or on specific cancers. In extract trials, adverse effects included stomach and gut problems, raised liver enzymes and, more rarely, insomnia, raised blood pressure and skin reactions. Quality of life improved slightly. For cancer-related death, no link was found with green tea intake. Prostate cancer in extract trials: RR 0.50; all-cancer incidence in observational studies (highest vs lowest intake): RR 0.83; cancer death: RR 0.99 (Prostate 0.18 to 1.36 (3 trials, 201 people, low certainty); all-cancer incidence 0.65 to 1.07 (low certainty); cancer death 0.91 to 1.07 (low certainty)) Methods, limits and funding Outcomes: Cancer incidence and mortality; adverse effects; quality of life Limitations: Few and small trials; observational studies can reflect other habits; conflicting results between study designs; mostly Asian populations. Funding and conflicts: Cochrane review; funding of included studies not stated in the abstract. Read: abstract
Hartley 2013 Green and black tea for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev · PMID 23780706 · DOI	Systematic review meta analysis	821 Healthy adults or adults at high risk of cardiovascular disease; 11 randomised trials of at least 3 months (7 green tea, 4 black tea)	Green tea (drink, powder or extract) Leaf Differed between trials At least 3 months · vs No intervention, placebo or minimal intervention	No trial reported heart-disease events. Green tea lowered total cholesterol, LDL cholesterol and blood pressure, but few studies contributed to each result and results were not stable when single trials were removed. The authors say the results should be treated with caution. Green tea: LDL cholesterol -0.64 mmol/L; total cholesterol -0.62 mmol/L; systolic BP -3.18 mmHg; diastolic BP -3.42 mmHg (LDL -0.77 to -0.52; total cholesterol -0.77 to -0.46; systolic -5.25 to -1.11; diastolic -4.54 to -2.30) Methods, limits and funding Outcomes: Heart and blood-vessel events; cholesterol; blood pressure Limitations: Few trials per analysis; risk of bias; results not stable to sensitivity analysis; no clinical-event data. Older review (searched October 2012). Read from the abstract only. Funding and conflicts: Cochrane review; funding of individual trials not stated in the abstract. Read: abstract
Hu 2018 The safety of green tea and green tea extract consumption in adults - Results of a systematic review. Regul Toxicol Pharmacol · PMID 29580974 · DOI	Systematic review	Laboratory toxicology studies and adverse events from 159 human intervention studies	Brewed green tea, tea in beverages or food, and concentrated catechin-rich green tea preparations (solid or bolus doses) Leaf Various	Liver was the target organ. Liver adverse events occurred in a dose-dependent way with a limited range of concentrated, catechin-rich preparations taken as large bolus doses, but not with brewed tea or extracts used in drinks or foods. The authors derived a safe intake level of 338 mg EGCG a day for solid bolus preparations and an observed safe level of 704 mg EGCG a day for beverage forms. Derived levels 338 mg and 704 mg EGCG a day (the authors' own estimates, not a regulator's limit). (Not applicable) Methods, limits and funding Outcomes: Hepatic adverse events Limitations: The safe levels are the authors' modelling from toxicology and trial adverse-event data. Read from the abstract only; some details of how they were derived are not visible. Funding and conflicts: Funding and competing interests not stated in the abstract. Read: abstract
Isomura 2016 Liver-related safety assessment of green tea extracts in humans: a systematic review of randomized controlled trials. Eur J Clin Nutr · PMID 27188915 · DOI	Systematic review meta analysis	34 randomised trials of green tea extracts, searched to December 2013	Green tea extracts Leaf extract Varied between trials Varied · vs Placebo or control	Liver-related adverse events were reported in 4 of 34 trials: 7 people (8 events) with extract and 1 person (1 event) with control. The few events were mostly mild liver-enzyme rises, and no serious liver events were reported. The authors conclude liver events are expected to be rare, though the result is not conclusive. Summary odds ratio 2.1 versus placebo (95% CI 0.5 to 9.8 (not statistically significant; very wide)) Methods, limits and funding Outcomes: Liver-related adverse events, including lab abnormalities Limitations: Very few events, so the review cannot rule out a real increase. Trials were often short and not designed to look for liver harm. Read from the abstract only. Funding and conflicts: Authors' funding and competing interests not stated in the abstract. Read: abstract
Jurgens 2012 Green tea for weight loss and weight maintenance in overweight or obese adults. Cochrane Database Syst Rev · PMID 23235664 · DOI	Systematic review meta analysis	Overweight or obese adults in randomised trials of 12 to 13 weeks (14 weight-loss studies; 2 weight-maintenance studies)	Green tea preparations (tea and extracts) Leaf Varied 12 to 13 weeks · vs Control	Green tea preparations gave a small weight loss that was not statistically significant, and the authors say it is not likely to be clinically important. Trials outside Japan found no difference (-0.04 kg). Eight Japanese trials could not be pooled and ranged from -0.2 to -3.5 kg. No significant effect on keeping weight off. Of 8 studies recording adverse events, 2 reported an event needing hospital care (judged unrelated). Weight: mean difference -0.04 kg (six non-Japanese trials, 532 people) (95% CI -0.5 to 0.4) Methods, limits and funding Outcomes: Body weight, BMI, waist circumference, adverse events Limitations: Trials were short (12 to 13 weeks) and different in tea type and amount; results differed between Japan and elsewhere. Older review (searched to 2012). Read from the abstract only. Funding and conflicts: Cochrane review; funding of individual trials not stated in the abstract. Read: abstract
Khalesi 2014 Green tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trials. Eur J Nutr · PMID 24861099 · DOI	Systematic review meta analysis	13 randomised trials (1995 to 2013) in adults	Green tea and green tea catechins (drink and extract) Leaf Varied Varied · vs Control	Green tea lowered blood pressure a little, with larger falls in people whose starting systolic pressure was 130 mmHg or higher and in studies using extract. It also lowered total and LDL cholesterol slightly; glucose and BMI changes were not significant. Systolic -2.08 mmHg; diastolic -1.71 mmHg; total cholesterol -0.15 mmol/L; LDL -0.16 mmol/L (Systolic -3.06 to -1.05; diastolic -2.86 to -0.56; total cholesterol -0.27 to -0.02; LDL -0.22 to -0.09) Methods, limits and funding Outcomes: Systolic and diastolic blood pressure; cholesterol; glucose; BMI Limitations: Small average changes in lab and blood-pressure numbers, not in heart attacks or strokes. Older review. Read from the abstract only. Funding and conflicts: Funding and competing interests not stated in the abstract. Read: abstract
Mansour-Ghanaei 2018 Green tea as a safe alternative approach for nonalcoholic fatty liver treatment: A systematic review and meta-analysis of clinical trials. Phytother Res · PMID 29947156 · DOI	Systematic review meta analysis	Four clinical trials in people with non-alcoholic fatty liver disease (searched to October 2017)	Green tea supplementation Leaf Not given in the abstract Not given in the abstract · vs Control	Pooled results showed lower ALT and AST liver-enzyme levels and lower BMI, triglycerides, total cholesterol and LDL with green tea; HDL and insulin-resistance score did not change significantly. The authors call the benefits potential. ALT -12.81 U/L; AST -10.91 U/L; BMI -2.08; triglycerides -31.87 mg/dL (ALT -18.17 to -7.45; AST -19.66 to -2.17) Methods, limits and funding Outcomes: ALT, AST, BMI, blood fats, insulin resistance Limitations: Only four studies, so it is very small. The abstract does not describe the green tea products or study quality. The title's phrase 'safe alternative' is stronger than the data allow, given the liver-injury reports with extracts. Funding and conflicts: Funding and competing interests not stated in the abstract. Read: abstract
Misaka 2022 Exposure of Fexofenadine, but Not Pseudoephedrine, Is Markedly Decreased by Green Tea Extract in Healthy Volunteers. Clin Pharmacol Ther · PMID 35678032 · DOI	Randomised crossover trial	10 10 healthy Japanese volunteers, fasting	Aqueous green tea extract solution with about 300 mg EGCG, taken with the drugs Leaf extract About 300 mg EGCG in a single drink (study amount, not advice) Single occasion per phase (2-phase crossover) · vs Water	With green tea extract, fexofenadine exposure (AUC) fell by 70% and the amount excreted in urine fell by 67%, compared with water. Pseudoephedrine was not affected. Lab tests suggest EGCG blocks the OATP1A2 transporter that helps absorb fexofenadine. Fexofenadine AUC down 70% (P < 0.001); urinary excretion down 67% (P < 0.001) (Not given in the abstract) Methods, limits and funding Outcomes: Blood levels of fexofenadine (an antihistamine) and pseudoephedrine Limitations: Only 10 healthy volunteers, one extract and one drug. Clinical effect on allergy symptoms was not measured. Funding and conflicts: Research support from non-US government sources; competing interests not stated in the abstract. Read: abstract
Oketch-Rabah 2020 United States Pharmacopeia (USP) comprehensive review of the hepatotoxicity of green tea extracts. Toxicol Rep · PMID 32140423 · DOI	Narrative review	Review of animal, human and case-report data on green tea extracts (GTE) and liver injury	Green tea extract (capsule/tablet and other supplement forms) Leaf extract Case reports link liver injury to EGCG intakes from about 140 mg to about 1,000 mg a day (as reported)	GTEs may contain solvent residues, pesticide residues, pyrrolizidine alkaloids and metals, but the review found no evidence these cause the liver injury. Catechin content varies with how the extract is made. Repeated bolus doses of extract on an empty stomach raise blood EGCG a lot. The injury pattern is hepatocellular. Case reports show big differences between people in susceptibility, possibly genetic. USP added a caution to its decaffeinated green tea extract monograph: take with food, do not use with a liver problem, stop and see a practitioner for signs of liver trouble. No effect size (review of case reports and toxicology). (Not applicable) Methods, limits and funding Outcomes: Liver injury; contaminants; labelling Limitations: Based on published case reports and animal data, which cannot give how often it happens. Read from the abstract only. Funding and conflicts: Authors from the US Pharmacopeia and academic centres; funding not stated in the abstract. Read: abstract
Sak 2022 Dietary Flavonoids with Catechol Moiety Inhibit Anticancer Action of Bortezomib: What about the other Boronic Acid-based Drugs? Curr Cancer Drug Targets · PMID 35578889 · DOI	Narrative review lab	Review of lab findings on green tea catechins and other catechol-containing flavonoids with the myeloma drug bortezomib	Green tea catechins Leaf	The review says the catechol group in green tea catechins binds the boronic acid group of bortezomib and abolishes its anticancer activity in the lab. Newer drugs of the same type have not been checked. It argues patients may need dietary guidance. This is laboratory evidence; the abstract gives no human outcome data. No numbers (Not applicable) Methods, limits and funding Outcomes: Chemical and anticancer-drug interaction Limitations: Lab evidence only; no clinical trial outcomes described in the abstract. Funding and conflicts: Single author; funding not stated in the abstract. Read: abstract
Siew-Keah 2023 An Update on Impacts of Epigallocatechin Gallate Co-administration in Modulating Pharmacokinetics of Statins, Calcium Channel Blockers, and Beta-blockers. Planta Med · PMID 37328148 · DOI	Narrative review	Review of studies of EGCG, green tea extract and brewed tea given with heart drugs	Green tea, green tea extract and EGCG Leaf Varied	The review concludes EGCG raises blood levels of several statins (simvastatin, fluvastatin, rosuvastatin) and of the calcium channel blocker verapamil, and lowers the bioavailability of beta-blockers (nadolol, atenolol, bisoprolol). Whether this changes how well the drugs work needs more study. No pooled numbers in the abstract (Not applicable) Methods, limits and funding Outcomes: Drug blood levels (pharmacokinetics) Limitations: A narrative review mixing small human and animal studies. Read from the abstract only. Funding and conflicts: Funding and competing interests not stated in the abstract. Read: abstract
Xu 2020 Effect of green tea consumption on blood lipids: a systematic review and meta-analysis of randomized controlled trials. Nutr J · PMID 32434539 · DOI	Systematic review meta analysis	3321 31 randomised trials in adults (normal weight and overweight or obese)	Green tea (drink and supplement forms) Leaf Not given in the abstract Varied · vs Control	Green tea lowered total and LDL cholesterol a little, did not change HDL, and the triglyceride change was not significant. Total cholesterol -4.66 mg/dL; LDL -4.55 mg/dL; triglycerides -3.77 mg/dL (not significant) (Total -6.36 to -2.96; LDL -6.31 to -2.80; triglycerides -8.90 to 1.37 (P = 0.15)) Methods, limits and funding Outcomes: Total, LDL and HDL cholesterol; triglycerides Limitations: Small average change. The abstract does not separate tea drinks from extract capsules, and the authors call for longer, more diverse trials. Funding and conflicts: Funding and competing interests not stated in the abstract. Read: abstract
s-livertox-green-tea LiverTox: Green Tea (NIH, NBK547925) · Source	Reference database n/a			Methods, limits and funding Read: not-read
s-nccih-green-tea NCCIH (NIH): Green Tea: Usefulness and Safety · Source	Reference page n/a			Methods, limits and funding Read: page text read 2026-10-26

What we do not know yet

No large, long-term trial showed that green tea extract prevents heart disease, stroke or cancer.
Most reviews pool tea drinks and extract capsules, so the effect of capsules alone is unclear.
The LiverTox entry could not be opened and was not read.
Pregnancy, children, allergy and kidney safety of extracts were not covered by the sources read.
Interactions with iron, folate and warfarin were not checked against a source.
Newer weight-loss and exercise trials were seen by title only.

How new research is added

New studies are found by a saved PubMed search and placed in a review queue before the page changes.

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 2

●

LDL cholesterol

Slightly lower in trials

The cholesterol carried in low-density particles, often called 'bad' cholesterol.

Moderate certainty

Results and what it means

Why it was measured

To see whether green tea lowers a heart-risk marker.

Statistical vs. clinical meaning

A small shift on average; it does not show fewer heart attacks.

Safety implication

Liver injury is rare but has been reported with concentrated extracts; see the Safety tab.

Study	Result	People	Product
¹³	Weighted mean difference -4.55 mg/dL (95% CI -6.31 to -2.80)	31 trials, 3,321 adults	Green tea (drink and supplement forms)
⁷	-0.16 mmol/L (95% CI -0.22 to -0.09)	13 trials in adults	Green tea and catechins

^{13 7 3}

●

Body weight

Little or no change in trials

How heavy someone is, in kilograms.

Low certainty

Results and what it means

Why it was measured

To see whether green tea helps weight loss.

Statistical vs. clinical meaning

Not likely to matter in practice, according to the Cochrane authors.

Safety implication

Two trials reported a hospital stay judged unrelated.

Study	Result	People	Product
⁶	Mean difference -0.04 kg (95% CI -0.5 to 0.4)	Six trials outside Japan, 532 overweight or obese adults	Green tea preparations for 12 to 13 weeks

⁶

Other 2

●

Systolic blood pressure

Slightly lower in trials

The top number in a blood pressure reading.

Low certainty

Results and what it means

Why it was measured

To see whether green tea lowers blood pressure.

Statistical vs. clinical meaning

Small and unstable.

Safety implication

NCCIH lists raised blood pressure as a side effect of extracts.

Study	Result	People	Product
⁷	-2.08 mmHg (95% CI -3.06 to -1.05)	13 trials in adults	Green tea and catechins
³	-3.18 mmHg (95% CI -5.25 to -1.11), not stable to sensitivity analysis	Green tea trials in healthy adults or those at high cardiovascular risk	Green tea drink, powder or extract

^{7 3 15}

●

ALT (alanine aminotransferase)

Lower in fatty-liver trials; higher at 800 mg EGCG a day or more in safety trials in trials

A liver enzyme; higher levels can signal liver stress.

Very low certainty

Results and what it means

Why it was measured

To see whether green tea changes liver markers in fatty liver, and to watch for harm.

Statistical vs. clinical meaning

The two findings point in different directions; the fatty-liver result rests on four small trials.

Safety implication

See the Safety tab.

Study	Result	People	Product
⁸	Mean difference -12.81 U/L (95% CI -18.17 to -7.45)	Four trials in people with non-alcoholic fatty liver disease	Green tea supplementation
¹	EFSA: statistically significant rise in transaminases at 800 mg or more EGCG a day as a supplement compared with control	Interventional trials in adults	Green tea catechin food supplements

^{8 1}

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

Rare but real liver injury, mostly with concentrated extracts. NCCIH says liver injury is uncommon but has been reported in people using green tea products, mainly extracts in tablet or capsule form. The US Pharmacopeia (USP) reviewed the cases and found a liver-cell injury pattern, with reports at EGCG intakes from about 140 mg to about 1,000 mg a day and large differences between people, possibly genetic. EFSA found that trials of 800 mg or more EGCG a day as a supplement raised liver enzymes (transaminases) versus control. A review of 34 trials found liver events in only a few people (summary odds ratio 2.1, 95% CI 0.5 to 9.8, not statistically significant), mostly mild enzyme rises and none serious, so it is rare but cannot be ruled out. Regulator guidance, review of case reports and meta analysis ^{15 10 1 5}
Taking extract on an empty stomach raises exposure. USP says repeated large bolus doses of green tea extract during fasting raise blood EGCG substantially, possibly because the liver's first-pass clearance gets saturated. Hu and colleagues found that liver adverse events happened with concentrated catechin-rich preparations taken as large bolus doses, but not with brewed tea or extracts consumed in drinks or food. These are findings about how exposure works, not advice about a dose. Review and systematic review ^{10 4}
Some people may be more susceptible because of their genes. NCCIH says people with a specific variant of a gene important in immune function appear especially susceptible to liver injury, and that 5 to 15 percent of Americans carry this variant. The page does not name the gene. USP also says susceptibility differs a lot between people, possibly for genetic reasons. Authoritative guidance ^{15 10}
Green tea extract can change blood levels of some medicines. NCCIH says high amounts of green tea lower blood levels of the beta-blocker nadolol and that extract can lower blood levels of the statin atorvastatin; a trial it funded also showed an interaction with the osteoporosis drug raloxifene. A randomised crossover trial of 10 people found a green tea extract drink cut exposure to the antihistamine fexofenadine by 70%. A 2023 review adds changes in blood levels of other statins, verapamil and beta-blockers. Tell a pharmacist about any extract you use. Authoritative guidance, randomised crossover trial and review ^{15 9 12}
Green tea contains caffeine. NCCIH notes green tea contains caffeine and advises people who are or might be pregnant to ask their provider about caffeine, because caffeine reaches a baby through breast milk and high levels can cause fussiness and poor sleep. Decaffeinated extracts are sold, but the USP caution about liver trouble applies to decaffeinated extract too. Authoritative guidance ^{15 10}

Side effects 3

Effect	How often	Severity and recovery	Evidence
Liver enzyme rises and, rarely, liver injury EFSA: significant transaminase rise in trials at 800 mg or more EGCG a day as a food supplement. This is a trial finding, not a safe-amount statement.	Reviewed trials: liver events in 4 of 34 trials, 7 people with extract and 1 with control (odds ratio 2.1, 0.5 to 9.8). Frequency in everyday users is not known.	Mostly mild enzyme rises in trials; case reports describe serious liver cell injury Not described in the abstracts read.	Meta analysis, review of case reports and regulator opinion ^{5 10 1 15}
Nausea, constipation and abdominal discomfort The Cochrane cancer review also lists stomach and gut disorders from extract trials.	Not given in the sources read.	Not graded; listed by NCCIH as common side effects of extract supplements Not described.	Authoritative guidance ^{15 2}
Raised blood pressure, insomnia and skin reactions NCCIH lists increased blood pressure as an extract side effect. Insomnia is likely linked to caffeine, but the abstract does not say so.	Reported as rarer effects in extract trials; frequency not given.	Not graded Not described.	Systematic review and authoritative guidance ^{2 15}

Liver

Liver is the main safety concern. USP's review found hepatocellular injury in case reports linked to EGCG intakes of about 140 to about 1,000 mg a day, with individual differences. EFSA found that 800 mg or more EGCG a day as a supplement raised transaminases in trials. A systematic review of 34 trials found liver events rare and mostly mild enzyme changes, but could not rule out a small excess (odds ratio 2.1, wide range 0.5 to 9.8). Hu and colleagues report liver events with concentrated catechin-rich preparations taken as large bolus doses, and not with brewed tea. The LiverTox entry for green tea could not be opened (bot-check), so it is not used. ^{10 1 5 4 15 14}

How often. Rare. A review of 34 trials found events in 4 trials; the true rate is not known.

Monitoring. USP's label caution asks people to stop and talk to a healthcare practitioner if liver symptoms occur, and not to use the extract with a liver problem. No monitoring schedule was found in the sources read.

. Case reports reviewed by USP link green tea extract to liver-cell injury at EGCG intakes of about 140 to about 1,000 mg a day, with big differences between people. Individual case details were not read.

This is a safety connection. It is not evidence that Green tea extract and EGCG supports liver health.

Medicines and supplements 8

With	Why it matters	Importance	Evidence	What to do
Nadolol (beta-blocker for blood pressure and heart problems) prescription	Green tea lowers the amount of nadolol reaching the blood (per NCCIH); a 2023 review says EGCG lowers bioavailability of nadolol, atenolol and bisoprolol.	NCCIH says high amounts of green tea reduce blood levels and therefore effectiveness. For the other beta-blockers the evidence is from the review.	Authoritative guidance and review Moderate certainty ^{15 12}	Ask a doctor or pharmacist before combining it with this medicine.
Atorvastatin and other statins prescription	NCCIH says green tea extract can reduce blood levels of atorvastatin; a 2023 review says EGCG increases blood levels of simvastatin, fluvastatin and rosuvastatin. The direction depends on the statin.	Whether these changes affect how well the statins work or their side effects is not shown in the sources read.	Authoritative guidance and review Low certainty ^{15 12}	Ask a doctor or pharmacist before combining it with this medicine.
Raloxifene (osteoporosis drug) prescription	Not described in the source.	NCCIH says an NCCIH-funded study showed an interaction between green tea and raloxifene. The direction and size were not stated on the page.	Authoritative guidance Low certainty ¹⁵	Ask a doctor or pharmacist before combining it with this medicine.
Fexofenadine (antihistamine) prescription	EGCG blocked the OATP1A2 transporter in lab tests, which helps fexofenadine get absorbed.	In 10 healthy fasting volunteers, a green tea extract drink with about 300 mg EGCG cut fexofenadine exposure (AUC) by 70% versus water. Pseudoephedrine was not affected. Allergy symptoms were not measured.	Randomised crossover trial Moderate certainty ⁹	Ask a doctor or pharmacist before combining it with this medicine.
Verapamil (calcium channel blocker) prescription	A 2023 review says EGCG raises verapamil's blood levels.	Clinical significance not shown in the abstract.	Review Low certainty ¹²	Ask a doctor or pharmacist before combining it with this medicine.
Bortezomib (myeloma drug) and similar boronic-acid cancer drugs prescription	The catechol group in green tea catechins binds the drug's boronic acid group and cancels its anticancer activity in laboratory tests.	The review says this has been shown in the lab only; whether it matters for patients was not shown in the abstract.	Lab evidence and review Low certainty ¹¹	People having cancer treatment should ask their oncology team before using green tea products.
Other liver-affecting medicines, alcohol or other herbal extracts prescription	No source read.	No source was read on combined liver risk, so nothing is claimed.	Not assessed Not enough evidence	Ask a doctor or pharmacist.
Iron supplements and iron in food supplement	Not established in the sources read.	A case report about tea and iron-deficiency anaemia was seen by title only and was not read, so no claim is made.	Not assessed Not enough evidence	Ask a doctor or pharmacist if you have anaemia.

Who should check first 5

Situation	Advice	Evidence
People with a liver problem, or who have had liver injury	USP's labelling caution says not to use decaffeinated green tea extract if you have a liver problem. Ask a doctor first.	Regulatory style label caution ¹⁰
Pregnancy and breastfeeding	The only source read, NCCIH, covers caffeine: keep it moderate in pregnancy and ask a healthcare provider, since caffeine reaches a baby through breast milk. No source read gives pregnancy safety data for concentrated extracts or EGCG, so none is claimed. Ask a doctor or pharmacist.	Authoritative guidance ¹⁵
Children	No source read covers extract supplements in children, so none is claimed. Ask a doctor or pharmacist.	Not assessed
People taking nadolol, a statin, raloxifene, fexofenadine, verapamil or bortezomib	See the interactions list. Ask a doctor or pharmacist before using extract.	Authoritative guidance, trial and review ^{15 9 12 11}
People sensitive to caffeine, or with high blood pressure	Green tea contains caffeine, and NCCIH lists raised blood pressure as an extract side effect. Ask a doctor.	Authoritative guidance ¹⁵

Overdose, product quality and regulators

Summary. The liver is the target organ. Concentrated, catechin-rich preparations taken as a large single dose, especially on an empty stomach, are the main concern. Brewed tea is not linked to the same pattern, though rare idiosyncratic liver injury has been reported after infusions too.

Animal. Hu and colleagues report that animal toxicology showed the liver as the target organ, strongly linked to bolus dosing by gavage and fasting, and to total catechin and EGCG content.

High dose or long term signals. EFSA: transaminase rises in trials at 800 mg or more EGCG a day as a supplement. USP: case reports from about 140 to about 1,000 mg EGCG a day.

Overdose response. Not described in the sources read. If you have signs of liver trouble, stop the product and see a clinician.

Genotoxicity. Not researched.

USP found that green tea extracts may contain solvent residues that can harm the liver, pesticide residues, pyrrolizidine alkaloids and metals, but found no evidence that these cause the liver injury. Catechin content varies a lot with how the extract is made. Label accuracy for current products was not researched.

Possible impurities in extracts. Hepatotoxic solvent residues, pesticide residues, pyrrolizidine alkaloids and elemental impurities may be present, but were not linked to the injury cases. ¹⁰

Variable catechin content. The catechin profile of green tea extracts varies significantly with manufacturing, so two products with the same name can carry very different EGCG loads. ¹⁰

Body	Action	Date
NCCIH (US National Institutes of Health) (United States)	No safety concerns reported for green tea as a drink in adults (caffeine aside). Side effects of extract supplements include nausea, constipation, abdominal discomfort and increased blood pressure. Liver injury is uncommon but reported, mainly with extract tablets or capsules. Notes interactions with nadolol, atorvastatin and raloxifene. States that the FDA has approved a prescription green tea extract ointment for external genital and perianal warts. source	2025-02
US Pharmacopeia (USP) (United States)	Added a caution to its Powdered Decaffeinated Green Tea Extract monograph: do not take on an empty stomach, take with food, do not use with a liver problem, and stop and see a practitioner if signs of liver trouble appear (abdominal pain, dark urine, jaundice). source	2020
EFSA (European Food Safety Authority) (European Union)	Catechins from traditionally prepared green tea infusions are in general considered safe at reported European intakes, though rare liver injury has been reported. In trials, 800 mg or more EGCG a day as a food supplement significantly raised serum transaminases compared with control. This describes trial findings, not a recommended amount. source	2018

When to get medical help

Yellow skin or eyes (jaundice), dark urine, pale stools, belly pain on the upper right, severe tiredness, itching or nausea that does not go away while using a green tea extract: stop the product and get medical help.
Fast heartbeat, chest pain, severe headache or very high blood pressure readings after caffeine-containing extract: seek medical help.
If you take any medicine on the interactions list, tell your doctor or pharmacist you use green tea extract, especially if the medicine seems to stop working.
If someone swallowed a large amount of extract or caffeine, call poison control or emergency services.

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

What is green tea extract?

It is a concentrated supplement made from the leaves of the tea plant, Camellia sinensis. Its main catechin is EGCG. It is sold as capsules and tablets, with or without caffeine.

^{15 1}

Is green tea extract the same as drinking green tea?

No. NCCIH reports no safety concerns for green tea as a drink in adults (caffeine aside), while liver injury has been reported mainly with extract tablets and capsules. A capsule can carry much more EGCG than a cup. Brewed tea has its own page.

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Does green tea extract help you lose weight?

Not in a way that matters. A Cochrane review found a small loss that was not statistically significant and unlikely to be useful in practice.

⁶

Does it lower cholesterol?

A little. Reviews of randomised trials found LDL cholesterol about 4.6 mg/dL lower on average, with no change in HDL. It is a small lab effect and does not show fewer heart attacks.

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Does it lower blood pressure?

A little, by about 2 mmHg in a review of 13 trials. NCCIH also lists raised blood pressure as an extract side effect, so results are mixed.

^{7 15}

Does green tea extract prevent cancer?

Not shown. A 2020 Cochrane review of 142 studies found inconsistent results and only limited evidence for any benefit.

Can green tea extract harm the liver?

Yes, rarely. NCCIH says liver injury is uncommon but has been reported, mainly with extract tablets and capsules. EFSA found raised liver enzymes in trials at 800 mg or more EGCG a day as a supplement. Stop and get help if you have yellow skin or eyes, dark urine or belly pain.

^{15 1 10 5}

Who should be extra careful?

People with a liver problem, people who take the medicines listed in the Safety tab, and anyone sensitive to caffeine. USP's label caution says not to use extract with a liver problem. NCCIH says people with a particular immune-gene variant seem more prone to liver injury.

^{10 15}

Does it interact with medicines?

Yes, some. NCCIH names nadolol, atorvastatin and raloxifene, and a small trial found fexofenadine exposure fell by 70%. Ask a pharmacist.

^{15 9 12}

Is it safe in pregnancy or for children?

The sources read cover only caffeine, which NCCIH says should be kept to moderate levels in pregnancy. No source read gives safety data on extracts or EGCG for pregnancy or children. Ask a doctor or pharmacist.

¹⁵

Should I take it on an empty stomach?

USP says repeated large doses of extract on an empty stomach raise blood EGCG a lot, and its label caution says not to take the extract on an empty stomach. Ask a doctor or pharmacist about your own situation.

¹⁰

Is the green tea ointment for warts the same thing?

No. It is a prescription skin medicine made from a specific extract, approved by the FDA for external genital and perianal warts. It says nothing about capsules.

¹⁵

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Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-26
Last substantive update: 2026-10-26
How we research: We started from our existing green tea extract summary, read the NCCIH page, and re-read PubMed abstracts for reviews, a regulator opinion, a crossover trial and case-report reviews. Only abstracts were read for studies. The NIH LiverTox page was blocked and is marked unread.
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. Trials of green tea products may have manufacturer links not stated in abstracts.

Sources 15

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

EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), Younes M, Aggett P, Aguilar F, Crebelli R, Dusemund B et al.. Scientific opinion on the safety of green tea catechins.. EFSA J. 2018. PMID 32625874. DOI 10.2903/j.efsa.2018.5239. (abstract)
Filippini T, Malavolti M, Borrelli F, Izzo AA, Fairweather-Tait SJ, Horneber M et al.. Green tea (Camellia sinensis) for the prevention of cancer.. Cochrane Database Syst Rev. 2020. PMID 32118296. DOI 10.1002/14651858.CD005004.pub3. (abstract)
Hartley L, Flowers N, Holmes J, Clarke A, Stranges S, Hooper L et al.. Green and black tea for the primary prevention of cardiovascular disease.. Cochrane Database Syst Rev. 2013. PMID 23780706. DOI 10.1002/14651858.CD009934.pub2. (abstract)
Hu J, Webster D, Cao J, Shao A. The safety of green tea and green tea extract consumption in adults - Results of a systematic review.. Regul Toxicol Pharmacol. 2018. PMID 29580974. DOI 10.1016/j.yrtph.2018.03.019. (abstract)
Isomura T, Suzuki S, Origasa H, Hosono A, Suzuki M, Sawada T et al.. Liver-related safety assessment of green tea extracts in humans: a systematic review of randomized controlled trials.. Eur J Clin Nutr. 2016. PMID 27188915. DOI 10.1038/ejcn.2016.78. (abstract)
Jurgens TM, Whelan AM, Killian L, Doucette S, Kirk S, Foy E. Green tea for weight loss and weight maintenance in overweight or obese adults.. Cochrane Database Syst Rev. 2012. PMID 23235664. DOI 10.1002/14651858.CD008650.pub2. (abstract)
Khalesi S, Sun J, Buys N, Jamshidi A, Nikbakht-Nasrabadi E, Khosravi-Boroujeni H et al.. Green tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trials.. Eur J Nutr. 2014. PMID 24861099. DOI 10.1007/s00394-014-0720-1. (abstract)
Mansour-Ghanaei F, Hadi A, Pourmasoumi M, Joukar F, Golpour S, Najafgholizadeh A et al.. Green tea as a safe alternative approach for nonalcoholic fatty liver treatment: A systematic review and meta-analysis of clinical trials.. Phytother Res. 2018. PMID 29947156. DOI 10.1002/ptr.6130. (abstract)
Misaka S, Ono Y, Taudte RV, Hoier E, Ogata H, Ono T et al.. Exposure of Fexofenadine, but Not Pseudoephedrine, Is Markedly Decreased by Green Tea Extract in Healthy Volunteers.. Clin Pharmacol Ther. 2022. PMID 35678032. DOI 10.1002/cpt.2682. (abstract)
Oketch-Rabah HA, Roe AL, Rider CV, Bonkovsky HL, Giancaspro GI, Navarro V et al.. United States Pharmacopeia (USP) comprehensive review of the hepatotoxicity of green tea extracts.. Toxicol Rep. 2020. PMID 32140423. DOI 10.1016/j.toxrep.2020.02.008. (abstract)
Sak K. Dietary Flavonoids with Catechol Moiety Inhibit Anticancer Action of Bortezomib: What about the other Boronic Acid-based Drugs?. Curr Cancer Drug Targets. 2022. PMID 35578889. DOI 10.2174/1568009622666220516102235. (abstract)
Siew-Keah L, Jie TH, Ang-Lim C, Bin LK, Yik-Ling C. An Update on Impacts of Epigallocatechin Gallate Co-administration in Modulating Pharmacokinetics of Statins, Calcium Channel Blockers, and Beta-blockers.. Planta Med. 2023. PMID 37328148. DOI 10.1055/a-2111-7319. (abstract)
Xu R, Yang K, Li S, Dai M, Chen G. Effect of green tea consumption on blood lipids: a systematic review and meta-analysis of randomized controlled trials.. Nutr J. 2020. PMID 32434539. DOI 10.1186/s12937-020-00557-5. (abstract)
. LiverTox: Green Tea (NIH, NBK547925). . . (not-read)
. NCCIH (NIH): Green Tea: Usefulness and Safety. . . (page text read 2026-10-26)

Where to buy

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

The amount of the active ingredient per serving, not just the front-label claim
A third-party testing mark (USP, NSF or ConsumerLab)
Other ingredients and allergens
Ask a pharmacist about interactions with your medicines

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.