Botanicals & Herbs

Green Tea Extract (EGCG)

Also known as: Camellia sinensis extract, EGCG, Epigallocatechin gallate, GTE

The catechin powerhouse — EGCG antioxidants for skin photoprotection and modest metabolic effects, with a liver-safety asterisk.

By IngredientWiki Editorial Team
Fact-checked by IngredientWiki Editorial Team
Updated 2026-09-26
3 min read

In short

Green tea extract concentrates the catechins of Camellia sinensis leaves — most famously EGCG, one of the most potent dietary antioxidants known. Topically, EGCG is backed by substantial research for protecting skin against UV damage and photoaging, which is why it appears in sunscreens and antioxidant serums. Orally, the evidence is more modest than marketing suggests: small effects on body fat and cardiovascular markers, reliable antioxidant activity, and — an important asterisk — rare cases of liver injury from high-dose concentrated extracts, particularly taken on an empty stomach.

EGCG is the main active catechin (up to ~50% of catechins)
Strong evidence for topical UV photoprotection
Oral weight-loss effects are real but small
High-dose extracts linked to rare liver injury

What is Green Tea Extract (EGCG)?

Green tea itself is one of the most-studied beverages on earth; the extract is the attempt to bottle its best parts. That effort succeeds in skincare, where EGCG's ability to soak up UV-generated free radicals and calm inflammation has made it a staple of antioxidant and after-sun formulations. The supplement story is more nuanced: consistent but small metabolic benefits, and a documented — if rare — liver risk profile that demands respect for dosing and timing. Drink the tea for free; use the extract for its concentration, carefully.

Where it comes from

Natural sources

Leaves of Camellia sinensis, minimally oxidized (unlike black tea)
Catechins — EGCG, EGC, ECG — are the active polyphenols
Also naturally contains caffeine and L-theanine

How it's made

Extracts standardize to catechins (often 45–50% EGCG); some products remove caffeine.

What it does in products

Benefits

UV photoprotection (topical)

strong evidence

Human and animal studies show topical EGCG reduces UV-induced redness, DNA damage markers, and photoaging changes — among the best-supported botanical sunscreen adjuvants.

Antioxidant and anti-inflammatory support

strong evidence

Systematic reviews confirm green tea catechins raise blood antioxidant capacity and reduce inflammatory markers.

Body fat and metabolism

moderate evidence

Meta-analyses of trials find green tea catechins produce a small (~1–2 kg over 12 weeks) fat loss advantage over placebo, with effects varying by ethnicity and caffeine intake.

Cardiovascular markers

moderate evidence

Trials show modest improvements in LDL cholesterol and blood pressure; observational data link green tea consumption with lower cardiovascular risk.

Side effects & safety

Stomach upset and nausea (common)Much more likely on an empty stomach — always take with food.

Insomnia or jitteriness (uncommon)From the caffeine content; choose decaffeinated extracts in the evening.

Liver injury (rare)Associated with high-dose concentrated extracts (especially >800 mg EGCG/day, fasted). Stop and seek care for jaundice or dark urine.

Safety considerations

High-dose extracts are not recommended in pregnancy; moderate tea consumption is generally fine. Discuss any supplement use with your provider.
May increase bleeding risk with anticoagulants (warfarin) — vitamin K is low in green tea, but check with your doctor.
Adds to caffeine from other sources; may affect absorption of iron and some medications.
Not for: Liver disease
Not for: Prior reaction to green tea extracts

How it's used

In supplements

Common dose: 250–500 mg of standardized extract (45–50% EGCG) per day with food. Keep EGCG intake below ~300 mg per dose, avoid empty-stomach dosing, and avoid combining multiple green tea products.

In skincare

Topical products typically use 0.5–5% green tea extract or EGCG in serums, creams, and sunscreens.

Regulatory status

Dietary supplement under DSHEA; green tea extract is also GRAS for use in beverages. The FDA has not approved it for any disease treatment.
GRAS (generally recognized as safe) for food use.

The liver-safety asterisk: why dosing matters

Green tea extract liver injury is real but rare, and the pattern is instructive: cases cluster around concentrated extracts delivering 800+ mg of EGCG daily, often on an empty stomach, sometimes in 'fat-burner' stacks. The mechanism is thought to involve oxidative stress from high catechol concentrations overwhelming the liver's defenses — a case where more is genuinely worse. Practical guardrails: 250–500 mg with food, no empty-stomach dosing, avoid stacking multiple green tea supplements, and stop immediately if you notice jaundice, dark urine, or unusual fatigue. Plain brewed green tea has never been linked to this risk in normal amounts.

Frequently asked questions

Does green tea extract really burn fat?

It produces a small, consistent effect — meta-analyses estimate roughly 1–2 kg additional loss over 12 weeks compared with placebo — not the dramatic claims on fat-burner labels. It works best alongside diet and exercise.

Is EGCG safe to take every day?

At 250–500 mg of extract with food, yes for most healthy adults. The risk profile changes with high doses on an empty stomach. Anyone with liver conditions should avoid concentrated extracts.

Can I just drink green tea instead of taking the extract?

Yes — 3–5 cups daily provides meaningful catechin intake with a safety record the extract cannot match. Supplements make sense when you want consistent, measured doses without the volume of tea.

The bottom line

Green tea extract earns its reputation topically — EGCG is a first-rate skin photoprotection antioxidant — and delivers modest metabolic benefits orally. Treat the supplement with respect: moderate doses, always with food, and never on an empty stomach.

References

Green tea. NCCIH (National Institutes of Health). https://www.nccih.nih.gov/health/green-tea
Green tea catechins and body weight — literature search. PubMed (National Library of Medicine). https://pubmed.ncbi.nlm.nih.gov/?term=green+tea+catechins+body+weight+meta-analysis
EGCG and skin photoprotection — literature search. PubMed (National Library of Medicine). https://pubmed.ncbi.nlm.nih.gov/?term=EGCG+skin+ultraviolet+photoprotection
EGCG compound summary. PubChem (National Library of Medicine). https://pubchem.ncbi.nlm.nih.gov/compound/65064