EGCG dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
A mid-stage study of 800 mg of EGCG a day in multiple sclerosis was stopped by its safety board.
Evidence grade for EGCG: Strong. The rule: at least two finished studies in people, and at least 1,000 people who took it. The sum on this page: 3 completed trials, 1,172 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 1,172
- Human studies
- 3
- Found nothing
- 1
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
3 completed trials, 1,172 people given it
5 effects reported, 3 unwanted, 2 wanted, by people using it, not a trial
Goal pages: Fat loss and metabolism, Brain, memory and mood, Ageing and longevity, Immune system and inflammation, Gut health
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
EGCG is the main active compound in green tea. It is sold in capsules at doses no tea drinker gets. At those doses it can damage the liver.
What people take it for
- Fat loss.
- Antioxidant protection.
- Brain health.
- Living longer.
What studies in people showed
The biggest study had 1,075 women taking 843 mg a day for a year. A liver enzyme rose in 6.7 percent of them, against 0.7 percent on a dummy pill. In 84 young adults with Down's syndrome, a year of EGCG made no difference on 13 of 15 thinking tests. A multiple sclerosis study was stopped early. 5 of the 7 people taking it had liver test problems. Europe's food safety body says 800 mg a day or more raises liver enzymes.
What people report
Reports, not study results
The good
- Brewed green tea at normal amounts did not show the liver warning.
- A few thinking scores improved in the Down's syndrome study.
The bad
- Liver damage is the big one. It rises with dose, and it stopped a study.
- There was more nausea and more skin trouble on the extract in the big study of women.
- Two batches with similar EGCG caused different amounts of liver harm.
- We have not collected user reports on this one yet.
Where these come from: The studies and the European safety review on this page. We have no forum reports on EGCG taken alone.
My bottom line
Drink the tea. Skip the high-dose capsules. If you take them anyway, get your liver enzymes checked, and do not take them on an empty stomach.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals EGCG has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Liver fat and liver health1,075 people · 1 study
- Cancer and tumours1,075 people · 1 study
- Memory and thinking87 people · 1 study · 1 found nothing
33 of the 36 indexed goals have no study of any kind behind EGCG
No study in people, animals or cells on this page reports a result for these. That does not prove EGCG does nothing for them. It does mean anything you have heard about EGCG and one of these did not come from a study cited here.
Show full evidence
What is EGCG?
A mid-stage study of 800 mg of EGCG a day in multiple sclerosis was stopped by its safety board. 5 of the 7 people on the treatment had abnormal liver tests, one of them serious. The biggest study of whether it helps, in 84 young adults with Down's syndrome over twelve months, found no real difference on 13 of 15 thinking tests.
This page covers EGCG on its own, and the strong, standard high-dose products built around it. Green tea extract as a whole has its own page on this site. That page covers the mouse lifespan test and the weight-loss studies. The two pages are meant to be read together.
EGCG is the green tea compound that gets credit for everything else in green tea. At supplement doses it has produced the most useful safety result on this page. An early study used Polyphenon E, a standard product that is 50 percent EGCG. Ten people with multiple sclerosis took 800 mg of EGCG a day. One stopped because of mild liver test problems. The study passed its early worth-continuing test, and a brain chemical linked to healthy nerve cells rose 10 percent on scans. The next study, with a dummy group, enrolled thirteen people. The safety board stopped it because 5 of 7 people taking Polyphenon E had abnormal liver tests, one of them serious, typically around 20 weeks in. Only two people reached the six-month visit, so the brain-protection question could not be answered at all. The authors rate this as top-grade evidence that some batches of Polyphenon E carry a high risk of liver damage.
That is an unusually clear liver warning. It is worth reading next to what happened on the benefit side. The TESDAD study was the biggest test of EGCG for a real-life result. Young adults with Down's syndrome took 9 mg per kg of body weight a day for twelve months, along with brain training. Eighty-four people were analysed. There was no real difference between groups on 13 of the study's 15 thinking tests, or on eight of nine everyday skills. Four measures did improve, and the authors called for large final-stage studies.
So the record on EGCG alone is this. A real liver-damage signal that rises with dose, clear enough that a safety board acted on it. And a benefit record that is mostly no-difference results, with a few wins inside a long list of tests.
How does EGCG work?
EGCG is a plant compound with a chemical group that makes it a strong antioxidant in a dish. It also lets it stick loosely to a huge range of proteins. That is why the research on how it works is enormous and scattered. Known effects include blocking DYRK1A, an enzyme made by a gene on chromosome 21, which is why it was tried in Down's syndrome. It also turns on the NRF2 cleanup pathway. How it damages the liver is not known. In studies the damage rises with dose, and it is more common when strong products are taken on an empty stomach. A gene analysis from a separate one-year study found that people with one version of a liver-clearing gene, UGT1A4, had about two to three times the rise in a liver enzyme. That points to differences in how people clear it, not to one toxic breakdown product.
What have studies in people found about EGCG?
A lot of human data, and unusually useful about harm. The studies that measured liver enzymes found a warning signal that rises with dose. It was strong enough to stop one study and to trigger a formal European safety review. The studies that measured real-life results mostly did not find them.
- Minnesota Green Tea Trial, 1,075 women, 843 mg of EGCG a day for one year: a liver enzyme rose in 6.7 percent, against 0.7 percent on a dummy pill. 1.3 percent had a serious liver-related problem.
- TESDAD, 84 young adults with Down's syndrome, 9 mg per kg a day for 12 months: no real difference on 13 of 15 thinking tests and 8 of 9 everyday skills. Clear gains on visual memory, two self-control measures and one school-skills score.
- Multiple sclerosis, mid-stage study, 800 mg of EGCG a day: stopped by the safety board. 5 of 7 on treatment had abnormal liver tests, one serious, typically around 20 weeks in.
- Multiple sclerosis, early study, same dose, ten people: passed its early test, with a brain chemical linked to healthy nerve cells up 10 percent. One person stopped over liver enzymes.
- European food safety review, 2018: supplement doses of 800 mg of EGCG a day or more clearly raise liver enzymes. Brewed tea at normal amounts does not.
- No human study has measured lifespan, deaths or any ageing measure with EGCG.
What this does not tell you: The brain-protection signal in multiple sclerosis rests on ten people with no comparison group, and on a stand-in scan measure. The proper test of it was never finished, because it was stopped for safety. In TESDAD, the clear results sit inside a list of 24 measures. The study itself calls for large final-stage studies to confirm them, and none has been reported here. None of this tells you what happens to a healthy person taking EGCG for years.
The state of the research
The site has a separate page for green tea extract as a whole. It covers the mouse lifespan test, a later reanalysis of it, and the weight-loss studies. Nothing on this page contradicts it. The two pages share the Minnesota study and the European safety review on purpose, because those two set the dose limit for the liver warning.
What this page adds is the picture for EGCG on its own. That matters because people take EGCG capsules at doses no tea drinker reaches. The study stopped by its safety board is the single most useful fact about this compound. It has a detail supplement buyers should think about. People in the early and later stages took capsules from different factory batches. The batches had similar EGCG but different amounts of other, minor tea compounds. The researchers could not explain the difference in liver damage by EGCG blood levels. Whatever caused it, the number on the label did not capture it.
A stand-in marker is a lab number used in place of the thing you actually care about. The idea is that if you move the number, you move the health result. That idea has failed often enough that it should be treated as a claim, not a fact. Homocysteine is the classic case. In studies that watch people, high homocysteine strongly predicts heart disease. Several cheap supplements can lower it reliably. But when studies lowered it and then counted heart attacks, the heart attacks did not go down. The lesson is not that markers are worthless. It is that a study reporting a marker has answered a smaller question than the one the buyer is asking. The page should say which question was answered.
The evidence, in charts
Fig. 1a · how many people
1,172people, across 3 studies in people cited here
| Study | People | Share |
|---|---|---|
| Food and Chemical Toxicology 2015 | 1,075 | 92% |
| TESDAD, Lancet Neurology 2016 | 87 | 7% |
| Journal of the Neurological Sciences 2015 | 10 | 1% |
One study holds 92% of these people, so the total rests more on one study than its size suggests. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
3 of 4 sources here are studies in people. The rest is not.
- Study in people · done in people375%
- Review of studies · sums up other studies125%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 3 different years, 2015 to 2018, counted from the list of sources on this page. The newest source on file is from 2018, more than five years ago. Research on it may have gone quiet.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Supplement
- Molecule weight
- 458.4 Da. A catechin, not a peptide.
- Half-life
- About 4 hoursShort, 1 to 6 hours
- Chain length
- None on file
Half-life as stated on file: Roughly 3 to 5 hours in plasma for free EGCG after an oral dose, with conjugated forms persisting longer.
No amino acid sequence is on file for EGCG, which is expected: a supplement is not built from amino acids.
The studies we cite
- Study in people2015Polyphenon E, non-futile at neuroprotection in multiple sclerosis but unpredictably hepatotoxic: Phase I single group and phase II randomized placebo-controlled studies.
The study was stopped because the supplement was damaging livers. Ten people with multiple sclerosis took 800 mg of EGCG a day for six months. One stopped over liver damage. Thirteen enrolled in the second stage, twelve started, and the safety board halted it. 5 of 7 people on Polyphenon E had abnormal liver tests, one severe, at a median of 20 weeks. Only two reached the six-month visit, so effectiveness could not be worked out. The maker supplied the product and reviewed the manuscript.
Phase 1: ten people with multiple sclerosis on 800 mg EGCG a day for six months, one discontinued for grade I liver function abnormalities, futility endpoint rejected with N-acetyl aspartate adjusted for creatine up 10 percent. Phase 2: thirteen enrolled, twelve started, and the data safety monitoring board stopped the study because 5 of 7 on Polyphenon E had abnormal liver function tests, one grade III, at a median of 20 weeks. Only two reached the six-month visit so the efficacy endpoint could not be analysed. Authors classify this as Class I evidence that some lots carry a high risk of hepatotoxicity. NIH funded; the manufacturer supplied drug and placebo and reviewed the manuscript.
- Study in people2016Safety and efficacy of cognitive training plus epigallocatechin-3-gallate in young adults with Down's syndrome (TESDAD): a double-blind, randomised, placebo-controlled, phase 2 trial.
A year of EGCG alongside cognitive training changed almost nothing. 87 adults aged 16 to 34 with Down's syndrome took EGCG or a dummy for a year, both groups doing the training, nobody knowing which. 13 of the 15 cognitive tests showed no difference, and neither did 8 of the 9 everyday skills measures. Gains showed up in visual recognition memory, in self-control, and in one functional academics score. Three positives out of two dozen measures needs a second trial.
87 adults aged 16 to 34 with Down's syndrome randomised to EGCG 9 mg/kg per day or placebo, both with cognitive training, for 12 months; 84 analysed. Differences were not significant on 13 of the 15 tests in the trial battery and on 8 of 9 adaptive skills. Significant gains appeared in visual recognition memory (6.23 percentage points), inhibitory control, and the ABAS-II functional academics score (5.49). No difference in adverse effects between groups. Registered as NCT01699711.
- Study in people2015The safety of green tea extract supplementation in postmenopausal women at risk for breast cancer: results of the Minnesota Green Tea Trial.
Green tea extract damaged some livers, at ten times the dummy group's rate. 1,075 women past menopause took an extract delivering 843 mg of EGCG a day, or a dummy, for a year. A liver enzyme rose in 36 women on the extract, 6.7 percent, against 4 on the dummy, 0.7 percent. 1.3 percent had a liver problem recorded as serious. Overall side effect rates were close, 75.6 against 72.8 percent. Funded by the US National Cancer Institute.
1,075 postmenopausal women randomised to an extract delivering 843 mg EGCG a day or placebo for one year. Alanine aminotransferase elevation in 36 women on extract (6.7 percent) against 4 on placebo (0.7 percent), p < 0.001, with 1.3 percent having an ALT-related serious adverse event. Overall adverse event rates were similar, 75.6 against 72.8 percent, with more nausea and skin events on extract. US National Cancer Institute funded.
- Review of studies2018Scientific opinion on the safety of green tea catechins.
A European food safety panel review. Catechins from normally brewed green tea are safe at the amounts people drink. But studies show that supplement doses of 800 mg of EGCG a day or more clearly raise liver enzymes compared with a dummy pill. Supplements give anywhere from 5 to 1,000 mg of EGCG a day. Heavy tea drinkers reach up to 866 mg a day.
European Food Safety Authority panel opinion. Catechins from traditionally brewed green tea are safe at reported intakes, while interventional trials show that supplemental doses at or above 800 mg EGCG a day produce a statistically significant increase in serum transaminases compared with control. Supplements provide between 5 and 1,000 mg EGCG a day; high-level tea drinkers reach up to 866 mg a day.
Common questions
Has EGCG been tested in people?
Yes. 1,172 people given it across 3 completed trials cited here, 1 of which found nothing. A mid-stage study of 800 mg of EGCG a day in multiple sclerosis was stopped by its safety board.
What is the EGCG dosage?
No human dose established. Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose. 3 completed trials, 1,172 people given it
Is EGCG FDA-approved?
Not an approved drug as a pill. An ointment made from green tea catechins is approved for genital warts on the skin. That is a different way of using it, for a different purpose. EGCG taken by mouth is sold as a dietary supplement.
How much EGCG is too much?
The European Food Safety Authority set the line at 800 mg a day from supplements. Above that, studies show a clear rise in liver enzymes. Brewed green tea at normal amounts does not carry that warning. The authority estimates typical drinkers get 90 to 300 mg a day, and heavy drinkers up to 866 mg. The multiple sclerosis study that was stopped for liver damage used exactly 800 mg a day.
Why was the multiple sclerosis trial stopped?
The safety board stopped it because 5 of the 7 people taking Polyphenon E got abnormal liver tests, one of them serious, typically around 20 weeks in. Only two people reached the six-month visit, so the study could not answer its own question about benefit. The authors rated it as top-grade evidence that some batches carry a high risk of liver damage.
Did EGCG improve cognition in Down's syndrome?
Partly, and less than the headlines said. In 84 young adults over twelve months, there was no real difference on 13 of the study's 15 thinking tests, or on eight of nine everyday skills. Visual memory, two self-control measures and one everyday-behaviour score did clearly improve. The authors called for large final-stage studies to confirm it.
Is EGCG an anti-ageing compound?
No human study has measured any ageing result with it. The lifespan evidence is about whole green tea extract in mice, and it is on this site's green tea extract page. There, the planned test found no effect in either sex. A later reanalysis found a 7 percent gain in typical lifespan in females, limited to midlife.
Is taking it with food safer?
Case reports, and the US Pharmacopeia's review of green tea products, show a pattern. Strong products taken on an empty stomach are more likely to cause harm than the same product taken with food. That is a pattern of risk, not a proven way to protect yourself. It does not remove the dose limit.