What kind of interaction is it?

Synergy: a documented combination effect that is stronger or more useful than either substance taken alone.

Is this interaction backed by published research?

Yes. NutriStack lists 1 citation row for the EGCG (Epigallocatechin Gallate) + Quercetin pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Supplement × Supplement·a synergy·Emerging evidence

EGCG (Epigallocatechin Gallate) + Quercetin

Q: Can I take EGCG (Epigallocatechin Gallate) and Quercetin together?

Yes. The combination of EGCG (Epigallocatechin Gallate) and Quercetin produces a measurable benefit. Quercetin inhibits the metabolism of EGCG, including COMT-mediated methylation and efflux transport, which can increase EGCG bioavailability and prolong its activity; both are also complementary antioxidant flavonoids.

Q: How does this affect a NutriStack Stack Score?

+2 to your Stack Score per scored synergy row.

Synergy Emerging evidence

Quercetin inhibits the metabolism of EGCG, including COMT-mediated methylation and efflux transport, which can increase EGCG bioavailability and prolong its activity; both are also complementary antioxidant flavonoids.

Supplement × Supplement

Open the interaction checker → Read the methodology

From the database

What the row says.

Every entry follows the same shape: what is happening, the mechanism, and the recommendation.

Substances

EGCG (Epigallocatechin Gallate) and Quercetin

Pair type

Synergy

Evidence

Emerging

Source citations

Scope

Supplement × Supplement

Last verified

June 4, 2026

SynergyEmerging evidence

What is happening. Quercetin inhibits the metabolism of EGCG, including COMT-mediated methylation and efflux transport, which can increase EGCG bioavailability and prolong its activity; both are also complementary antioxidant flavonoids.

Mechanism. Quercetin inhibits COMT and efflux transporters (e.g., multidrug resistance proteins), reducing EGCG methylation and clearance and raising its plasma concentrations.

Recommendation. Pairing is reasonable and may modestly enhance EGCG levels. Take with food and avoid high combined doses on an empty stomach to limit GI and hepatic risk.

Stack Score

How it moves the number.

Effect on the composite score

If both EGCG (Epigallocatechin Gallate) and Quercetin are in the same stack, this pair applies +2 to your Stack Score (per scored synergy row).

The full algorithm, the clamping rules, and four worked stacks are at /methodology/stack-score.

Sources

Sources, by evidence tier.

Every claim on this page is cited. PMIDs link straight to PubMed.

Reference material

1Wang P, Heber D, Henning SM. Quercetin increased the antiproliferative activity of green tea polyphenol (-)-epigallocatechin gallate in prostate cancer cells. Nutrition and Cancer. 2012.Needs sourceNo link

Check your full routine

One pair was the worked example.

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Open the interaction checker → Browse the research index