flavan-3-ols

PhytochemicalBest with a meal

What is it

Flavan-3-ols are a class of plant polyphenols (also called flavanols) that include catechin, epicatechin, and proanthocyanidins. They are found abundantly in cocoa, tea, apples, berries, and grapes.

Evidence for 3 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Cardiovascular / blood pressure

Strong Evidence

Meta-analyses and large trials including COSMOS show flavan-3-ol intake of 400-600 mg/day is associated with modest improvements in blood pressure and reduced cardiovascular events.

Endothelial function

Strong Evidence

Numerous RCTs show flavan-3-ols improve flow-mediated dilation, a measure of vascular health, within hours and with sustained intake.

Cognitive function (aging)

Limited Evidence

Some trials suggest modest benefits to cognitive performance and cerebral blood flow in older adults; results are mixed.

How it works

Flavan-3-ols influence vascular function by stimulating endothelial nitric oxide production, which supports healthy blood flow and blood pressure. They also have antioxidant activity and modulate platelet aggregation. In the gut, larger polymeric flavan-3-ols are metabolized by gut bacteria into smaller phenolic acids that enter the bloodstream and contribute to systemic effects. The Cocoa Supplement and Multivitamin Outcomes Study (COSMOS) provided large-scale data supporting cardiovascular benefits at sustained intakes.

Dosage

The 2022 Academy of Nutrition and Dietetics expert consensus recommended 400-600 mg/day of flavan-3-ols for cardiometabolic benefit. Equivalent to roughly 2-4 cups of green tea or a serving of high-flavanol cocoa.

When and how to take it

Spread across the day with meals. Caffeinated sources (green tea) earlier in the day. Consistent daily intake matters more than timing.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Cocoa flavanols (lavado-style or extract)

Used in COSMOS and many cardiovascular trials.

Non-alkalized cocoa retains more flavanols.

Green tea catechins (EGCG, ECG)

Common in green tea extract supplements.

Absorption is moderate; taking on empty stomach increases liver risk.

Safety

Safe from food sources. Concentrated extracts can cause mild GI upset. Very high doses of green tea extract have been linked to rare liver injury.

Who should be cautious

People on blood thinners or blood pressure medications should monitor. Pregnancy is generally fine at dietary intake levels. Avoid concentrated green tea extracts on an empty stomach due to liver concerns.

Interactions

May enhance effects of blood pressure and anticoagulant medications. Green tea catechins can reduce absorption of non-heme iron and some drugs (including certain statins and beta-blockers).

Food sources

Cocoa, dark chocolate (>70%)

Amount
30 g
%DV
—

Green tea, brewed

Amount
1 cup
%DV
—

Apples (with skin)

Amount
1 medium
%DV
—

Berries

Amount
1 cup
%DV
—

Frequently asked questions

How much chocolate do I need?⌄

Roughly 30-40 g of high-flavanol dark chocolate provides a meaningful portion of the 400-600 mg daily recommendation, depending on processing.

Is supplementation better than food?⌄

Food sources are well-supported. Extracts can deliver concentrated doses but vary in quality and may carry liver risks at very high doses.

References

flavan-3-ols on Wikidata — Wikidata link

flavan-3-ols on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on flavan-3-ols (PubMed search) — PubMed link

Track flavan-3-ols with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

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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.