Gallocatechin Gallate

PhytochemicalCatechin/polyphenolBest taken away from food

What is it

Gallocatechin gallate (GCG) is a catechin polyphenol found primarily in green tea and other Camellia sinensis products. It is structurally similar to the better-known epigallocatechin gallate (EGCG) and shares antioxidant activity.

Evidence for 1 use

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Antioxidant activity

Limited Evidence

GCG demonstrates antioxidant activity in vitro alongside other green tea catechins. Clinical translation specifically to GCG (vs total catechins) is limited.

How it works

GCG is a flavan-3-ol that acts as an antioxidant in vitro and can scavenge reactive oxygen species. It may also modulate gene expression related to inflammation and lipid metabolism. In green tea extracts, GCG appears as a minor catechin compared to EGCG. Some research suggests GCG forms when EGCG is heated (e.g., during brewing), explaining why brewed teas contain meaningful GCG. Human clinical data specifically isolating GCG effects from EGCG and other tea catechins is limited.

Dosage

No established dose. As a tea catechin, intake depends on green tea consumption (a cup of green tea provides 50-150 mg total catechins). Standardized GCG supplements are rare.

When and how to take it

If consumed as tea, between meals can preserve iron absorption from food. Concentrated catechin supplements are best taken with food to reduce hepatotoxicity risk.

1 commercial form

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Green tea catechin

Found mostly as part of green tea extract, not as standalone GCG.

Oral bioavailability of catechins is modest; absorption varies.

Safety

At dietary intakes from tea, considered safe. High-dose concentrated green tea extracts (containing GCG plus other catechins) have been linked to rare cases of liver injury; the EFSA recommends limiting EGCG to under 800 mg/day from supplements.

Who should be cautious

People with liver disease should avoid concentrated catechin supplements. Pregnant and breastfeeding women should limit to dietary tea levels.

Interactions

Tea catechins can interact with iron absorption (decrease) and may affect anticoagulant/antiplatelet pathways at high doses. Caution with hepatotoxic medications.

Food sources

Green tea, white tea

Amount
Variable; brewing increases GCG via EGCG epimerization
%DV
—

Frequently asked questions

Is GCG better than EGCG?⌄

They are structurally similar with overlapping activities. GCG has been studied less. Brewed tea contains both because heat converts some EGCG to GCG.

References

Gallocatechin Gallate on Wikidata — Wikidata link

Gallocatechin Gallate (ChEBI:156284) — ChEBI link

Gallocatechin Gallate (PubChem CID 5276890) — PubChem link

Gallocatechin Gallate on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Gallocatechin Gallate (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.