Head to head
EGCG against Green tea extract
The isolated catechin and the extract it comes from, which people treat as the same purchase. Both carry the same signal: a phase 2 of 800 mg EGCG daily in multiple sclerosis was stopped after 5 of 7 treated participants developed abnormal liver function tests, and in 1,075 women taking 843 mg EGCG daily for a year liver enzyme elevations occurred in 6.7 percent against 0.7 percent on placebo.
Column A
EGCGEpigallocatechin-3-gallate, the principal catechin of green tea
A phase 2 trial of 800 mg EGCG a day in multiple sclerosis was stopped by its data safety monitoring board after 5 of 7 participants on treatment developed abnormal liver function tests, one of them grade III. The largest efficacy trial, 84 young adults with Down's syndrome over twelve months, found no significant difference on 13 of 15 cognitive tests.
Column B
Green tea extractGreen tea extract (Camellia sinensis catechin concentrate, EGCG-rich)
Did not extend mouse lifespan by the Interventions Testing Program's protocol test; a Gehan reanalysis found a 7 percent female median gain. In people, the largest trial (1,075 women, one year at 843 mg EGCG a day) found liver enzyme elevations in 6.7 percent against 0.7 percent on placebo, and a Cochrane review found no clinically meaningful weight loss.
Side by side, on the facts we can check
| Attribute | EGCG | Green tea extract |
|---|---|---|
| Category | Antioxidant | Longevity |
| FDA status | Not an approved drug in oral form. A green tea catechin ointment is approved topically for external genital warts, which is a different route and purpose. Oral EGCG is sold as a dietary supplement. | Not an approved drug. Sold as a dietary supplement. The lifespan signal is a Gehan-only reanalysis result in female mice. Supplemental doses at or above 800 mg EGCG a day have a documented liver enzyme signal in randomised trials (EFSA 2018). |
| Half-life | Roughly 3 to 5 hours in plasma for free EGCG after an oral dose, with conjugated forms persisting longer. | Not reported |
| Molecular weight | 458.4 Da. A catechin, not a peptide. | Not reported |
| Mechanism | A polyphenolic catechin with a galloyl group that gives it high antioxidant activity in vitro and lets it bind a wide range of proteins non-specifically, which is why the mechanism literature for it is enormous and unfocused. Documented activities include inhibition of DYRK1A, the chromosome 21 kinase that motivated the Down's syndrome trials, NRF2 pathway activation, and effects on laminin receptor signalling. The liver injury mechanism is not established. It is dose-related in trials and more frequent when concentrated preparations are taken fasted. A secondary genetic analysis of a separate one-year trial found that carriers of a UGT1A4 variant had roughly two to three times the rise in alanine aminotransferase of non-carriers, which points at differences in catechin glucuronidation capacity rather than at a single toxic metabolite. | EGCG and the other catechins are polyphenols with antioxidant activity in vitro and a wide range of enzyme and signalling effects in cell culture; the extract also contains caffeine unless decaffeinated, which accounts for much of what people feel and some of the modest thermogenic effect studied for weight loss. The liver toxicity mechanism in people is not fully established; it is dose-related in trials, more frequent when taken fasted, and in a secondary analysis of the Minnesota trial the rise in ALT was larger in carriers of a UGT1A4 variant, pointing to catechin glucuronidation capacity. The ITP selected the extract for its antioxidant properties. Why a Gehan-only midlife signal appeared in females and not males was not investigated. |
| Human studies cited | 3 | 2 |
| Legal status, US | Sold as a supplement | Sold as a dietary supplement |
Frequently asked questions
What is the difference between EGCG and Green tea extract?
EGCG: A phase 2 trial of 800 mg EGCG a day in multiple sclerosis was stopped by its data safety monitoring board after 5 of 7 participants on treatment developed abnormal liver function tests, one of them grade III. The largest efficacy trial, 84 young adults with Down's syndrome over twelve months, found no significant difference on 13 of 15 cognitive tests. Green tea extract: Did not extend mouse lifespan by the Interventions Testing Program's protocol test; a Gehan reanalysis found a 7 percent female median gain. In people, the largest trial (1,075 women, one year at 843 mg EGCG a day) found liver enzyme elevations in 6.7 percent against 0.7 percent on placebo, and a Cochrane review found no clinically meaningful weight loss.
Which has stronger research evidence, EGCG or Green tea extract?
This database does not grade compounds. It counts what was run in people: 3 of the 4 studies cited on the EGCG profile were human work, against 2 of 7 for Green tea extract. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are EGCG and Green tea extract FDA-approved?
EGCG: Not an approved drug in oral form. A green tea catechin ointment is approved topically for external genital warts, which is a different route and purpose. Oral EGCG is sold as a dietary supplement.. Green tea extract: Not an approved drug. Sold as a dietary supplement. The lifespan signal is a Gehan-only reanalysis result in female mice. Supplemental doses at or above 800 mg EGCG a day have a documented liver enzyme signal in randomised trials (EFSA 2018)..
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.