Caffeic Acid
Caffeic acid is a phenolic compound found widely in coffee (despite the name, unrelated to caffeine), fruits, vegetables, olive oil, and propolis. It has strong antioxidant activity in lab settings, and its phenethyl ester (CAPE) shows anticancer activity in cell and animal studies. Human evidence for isolated caffeic acid supplementation is essentially absent — most claims rest on mechanism, not on controlled trials.
Quick decision guide
May help most
Researchers and educators interested in dietary polyphenol biology. Not a typical consumer-supplement use case.
Common dosing range
No standard supplement dose. Dietary intake from coffee, fruits, and vegetables totals 0.5–1 g/day in typical Western diets. Isolated supplements rarely sold.
When to expect effects
Not characterized — no clinical-outcome trials in humans.
Watch out for
Most marketed claims (cancer prevention, anti-inflammatory benefit) are based on cell or animal data and don't translate to clinical outcomes in humans at oral doses.
Evidence snapshot
What is it
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
Antioxidant activity (mechanism) Limited Evidence | Strong in vitro; low μM plasma concentrations in vivo limit clinical translation | Population-level dietary intake from food sources — useful contribution to total dietary antioxidant intake | Not characterized as a clinical endpoint |
Blood pressure (chlorogenic acid → caffeic acid path) Limited Evidence | ≈4 mmHg systolic BP reduction in small chlorogenic acid trials; caffeic acid contribution unclear | Adults with borderline hypertension exploring dietary polyphenol approaches | Weeks (in chlorogenic acid trials) |
Cancer (preclinical only — CAPE and caffeic acid) Mixed Evidence | No human cancer trial data; preclinical signals at concentrations not achievable by oral dosing | Not applicable — no evidence supports clinical cancer use | Not established in humans |
Anti-inflammatory effects (clinical) Mixed Evidence | Robust in vitro; no human RCTs of isolated supplement | Population-level dietary patterns (Mediterranean, plant-forward diet) | Not characterized in humans |
Antioxidant activity (mechanism)
- Effect
- Strong in vitro; low μM plasma concentrations in vivo limit clinical translation
- Best fit
- Population-level dietary intake from food sources — useful contribution to total dietary antioxidant intake
- Time
- Not characterized as a clinical endpoint
Blood pressure (chlorogenic acid → caffeic acid path)
- Effect
- ≈4 mmHg systolic BP reduction in small chlorogenic acid trials; caffeic acid contribution unclear
- Best fit
- Adults with borderline hypertension exploring dietary polyphenol approaches
- Time
- Weeks (in chlorogenic acid trials)
Cancer (preclinical only — CAPE and caffeic acid)
- Effect
- No human cancer trial data; preclinical signals at concentrations not achievable by oral dosing
- Best fit
- Not applicable — no evidence supports clinical cancer use
- Time
- Not established in humans
Anti-inflammatory effects (clinical)
- Effect
- Robust in vitro; no human RCTs of isolated supplement
- Best fit
- Population-level dietary patterns (Mediterranean, plant-forward diet)
- Time
- Not characterized in humans
Evidence for 4 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
Antioxidant activity (mechanism)
Mechanism onlyCaffeic acid is among the most potent dietary polyphenols by in-vitro free-radical scavenging assays (ORAC, DPPH). It modulates Nrf2 antioxidant pathways and inhibits lipid peroxidation in cell cultures. The clinical-outcome translation is unclear: oral caffeic acid plasma levels rarely reach the μM concentrations needed for the in-vitro effects, and most circulating caffeic acid is conjugated (sulfate/glucuronide) rather than free.
Bottom line: Real mechanism; uncertain clinical translation at supplement doses.
Blood pressure (chlorogenic acid → caffeic acid path)
Supplement benefitCoffee chlorogenic acid (which is metabolized in the gut to caffeic + quinic acid) has produced modest BP reductions (~4 mmHg systolic) in small RCTs. The active component(s) and dose-response aren't well characterized, and trials have been small and short. The signal is plausible but not robust enough to recommend isolated caffeic acid supplementation for BP. Dietary coffee intake at moderate amounts is associated with neutral or modestly favorable BP effects.
Bottom line: Eat the foods (coffee, fruit, vegetables); the isolated supplement isn't worth it.
Cancer (preclinical only — CAPE and caffeic acid)
Mechanism onlyCAPE (caffeic acid phenethyl ester, from propolis) shows anticancer activity in dozens of cell-line and animal models — apoptosis induction, NF-κB inhibition, anti-angiogenic and antimetastatic effects. There are no published human cancer clinical trials of isolated caffeic acid or CAPE. The translation from cell-culture concentrations (often 10–100 μM) to achievable plasma concentrations after oral dosing (<1 μM) is the key gap.
Bottom line: Interesting cell-biology work; don't use as a cancer intervention.
Anti-inflammatory effects (clinical)
Mechanism onlyCaffeic acid inhibits NF-κB activation and reduces inflammatory cytokine release in cell-culture and animal models. Human RCTs of isolated caffeic acid for inflammatory conditions are absent. Inflammatory biomarker changes from diets rich in caffeic-acid-containing foods (Mediterranean diet, coffee consumption) probably reflect the diet pattern as a whole rather than caffeic acid specifically.
Bottom line: Eat the foods; don't supplement.
How it works
How to take it
What to track
Bottom line: Get caffeic acid from coffee, fruits, vegetables, and a varied diet. Don't pay for isolated supplements — there's no clinical evidence to support a dose or outcome.
5 commercial forms
Compare the main delivery options and what they’re best suited for.
Dietary caffeic acid (from food)
Best sourceCoffee, fruits (especially berries), vegetables, olive oil, herbs. Total dietary intake of 0.5–1 g/day in typical Western diets. The form that has any human evidence behind it.
Plasma free caffeic acid stays low (μM range) after extensive gut microbiota + first-pass metabolism.
Coffee chlorogenic acids
Major dietary sourceCoffee provides 500–800 mg chlorogenic acids per cup, which hydrolyze in the gut to caffeic + quinic acid. The single biggest dietary source for most adults.
About 30% absorbed in the small intestine; the rest reaches the colon for microbiota-mediated hydrolysis.
Propolis (CAPE source)
Bee productBee propolis contains CAPE (caffeic acid phenethyl ester) at variable concentrations depending on the propolis source. Marketed for general wellness and immune support. Allergy risk in bee-sensitive individuals.
CAPE bioavailability after oral propolis is variable; standardization quality matters.
Isolated caffeic acid (supplement)
Limited availabilityRarely sold as a standalone consumer supplement. No clinical-outcome RCTs to support dosing or use case.
Same first-pass metabolism limits as dietary caffeic acid.
Pharmacological CAPE (research / experimental)
Research onlyUsed in cell-culture and animal cancer research at concentrations not achievable by oral propolis. Not a consumer product.
Concentrations used in research are far above achievable plasma levels from oral dosing.
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Serious risks
CAPE from propolis can cause severe allergic reactions (including anaphylaxis) in people with bee or pollen allergies. Avoid propolis if you have a known bee-product allergy.
Animal studies with very high-dose caffeic acid have shown renal carcinogenicity at supraphysiological doses (gram-per-kg range). Not relevant at human dietary intakes; raises caution about high-dose isolated supplementation in humans where long-term safety is unstudied.
Who should avoid it
- People with bee or propolis allergies — avoid CAPE-containing propolis products.
- Pregnant women using isolated supplements — no safety data; dietary intake from food is fine.
- Anyone hoping isolated caffeic acid will treat or prevent serious disease — the evidence base doesn't support this.
Pregnancy & breastfeeding
Dietary intake from coffee, fruits, and vegetables at typical levels is safe during pregnancy and breastfeeding. Isolated caffeic acid supplements haven't been studied in pregnancy and should be avoided — there's no clinical reason to take them. Propolis (which contains CAPE) is also generally avoided in pregnancy due to allergy and limited safety data.
Bottom line: Safe as a dietary component. Avoid isolated high-dose supplements and propolis if you have bee allergies.
Interactions
Antioxidant supplements during chemotherapy or radiation may theoretically interfere with treatment-induced oxidative damage to cancer cells. Avoid concentrated antioxidant supplementation during active cancer treatment unless your oncologist approves.
Propolis-containing products (which provide caffeic acid + CAPE) have been reported to interact with warfarin in case reports. Pure caffeic acid supplements at typical doses have no established interaction. Tell your anticoagulation clinic if you start propolis.
Polyphenols (including caffeic acid) can bind non-heme iron in the gut and reduce its absorption when taken in the same meal. Mostly a coffee/tea-with-iron-pill issue. Separate iron supplements from polyphenol-rich foods by 1–2 hours.
Food sources
| Food | Amount | %DV |
|---|---|---|
| Coffee, brewed | 1 cup / 8 oz (~70–350 mg caffeic acid equivalents from chlorogenic acid) | — |
| Sunflower seeds | 1 oz (~80 mg caffeic acid equivalents) | — |
| Apples (with skin) | 1 medium (~10 mg) | — |
| Pears (with skin) | 1 medium (~6 mg) | — |
| Cranberries | ½ cup (~20 mg) | — |
| Blueberries | ½ cup (~10 mg) | — |
| Cherries | ½ cup (~10 mg) | — |
| Olive oil, extra-virgin | 1 Tbsp (~1–2 mg) | — |
| Eggplant | ½ cup cooked (~70 mg) | — |
| Thyme, fresh | 1 Tbsp (~5 mg) | — |
Coffee, brewed
- Amount
- 1 cup / 8 oz (~70–350 mg caffeic acid equivalents from chlorogenic acid)
- %DV
- —
Sunflower seeds
- Amount
- 1 oz (~80 mg caffeic acid equivalents)
- %DV
- —
Apples (with skin)
- Amount
- 1 medium (~10 mg)
- %DV
- —
Pears (with skin)
- Amount
- 1 medium (~6 mg)
- %DV
- —
Cranberries
- Amount
- ½ cup (~20 mg)
- %DV
- —
Blueberries
- Amount
- ½ cup (~10 mg)
- %DV
- —
Cherries
- Amount
- ½ cup (~10 mg)
- %DV
- —
Olive oil, extra-virgin
- Amount
- 1 Tbsp (~1–2 mg)
- %DV
- —
Eggplant
- Amount
- ½ cup cooked (~70 mg)
- %DV
- —
Thyme, fresh
- Amount
- 1 Tbsp (~5 mg)
- %DV
- —
Choosing a product
What to look for on the label — and what to be skeptical of.
Look for…
Be skeptical of…
Frequently asked questions
Is caffeic acid the same as caffeine?⌄
No. They are completely different compounds despite both being found in coffee. Caffeic acid is a polyphenol with no stimulant effect; caffeine is an alkaloid stimulant.
Should I take a caffeic acid supplement?⌄
Probably not as a standalone. Most evidence relates to dietary intake (especially coffee) or to CAPE from propolis. Direct caffeic acid supplements have limited research.
Does coffee provide meaningful caffeic acid?⌄
Yes. Coffee is the dominant dietary source for most adults, providing hundreds of mg per cup (mostly as chlorogenic acid, which yields caffeic acid).
References by claim
Track Caffeic Acid with Pilora
Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.
Coming to App StoreDisclaimer: 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.