Coumaric acid

PhytochemicalPhenolic acidBest with a meal

What is it

Coumaric acid is a hydroxycinnamic acid found widely in plant foods. The most common isomer in supplements and research is p-coumaric acid, present in tomatoes, carrots, peanuts, garlic, and many other fruits and vegetables.

Evidence for 1 use

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

Antioxidant intake (dietary)

Limited Evidence

P-coumaric acid contributes to the antioxidant content of a diverse plant-based diet. Specific clinical benefits from isolated supplements are not well established.

How it works

P-coumaric acid is a phenolic antioxidant that scavenges free radicals and may modulate enzymes involved in oxidative stress. It is also a precursor to other plant polyphenols including caffeic, ferulic, and sinapic acids. Dietary p-coumaric acid is partly absorbed in the small intestine and partly fermented in the colon. Bioavailability is modest and effects in humans appear small at typical dietary doses. Supplementation has been studied mostly in laboratory and animal models for antioxidant, anti-inflammatory, and possible neuroprotective effects.

Dosage

There is no established RDA. Typical dietary intake is in the milligram range per day. Supplements vary substantially; clinically meaningful supplemental doses have not been well established.

When and how to take it

No specific timing recommendation. Often taken with meals as part of a polyphenol blend.

1 commercial form

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P-coumaric acid (isolated)

Used in some polyphenol blends.

Modest absorption; partly metabolized in the gut.

Safety

Coumaric acid is widely consumed in food and has a long history of safe dietary exposure. Concentrated supplement use has limited dedicated safety data. Mild GI symptoms are uncommon.

Who should be cautious

No specific precautions apply for normal dietary exposure. Pregnancy and breastfeeding safety of concentrated supplements has not been formally studied.

Interactions

No well-characterized drug interactions at typical dietary or supplemental doses.

Food sources

Tomatoes

Amount
1 medium
%DV
—

Garlic

Amount
1 clove
%DV
—

Carrots

Amount
1 medium
%DV
—

Peanuts

Amount
1 oz
%DV
—

Frequently asked questions

Do I need a coumaric acid supplement?⌄

Most people get coumaric acid in normal amounts from a plant-rich diet. Specific supplementation has limited clinical evidence.

Is it the same as coumarin?⌄

No. Coumaric acid and coumarin are different chemicals. Coumarin is a sweet-smelling compound from tonka bean and cinnamon and has its own pharmacology, including potential liver toxicity at high doses.

References

Coumaric acid on Wikidata — Wikidata link

Coumaric acid (ChEBI:23401) — ChEBI link

Coumaric acid on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Coumaric acid (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.