Caffeic Acid
A hydroxycinnamic acid and naturally occurring plant phenolic compound.
Caffeic Acid: Food Sources, Chlorogenic Acid & What Research Shows
Caffeic acid is a naturally occurring phenolic compound found throughout the plant kingdom. It belongs to the hydroxycinnamic acid family and occurs in fruits, vegetables, coffee, herbs, grains, and other plant foods.
In foods, caffeic acid does not always occur as a free molecule. Much of it can be chemically bound or incorporated into larger compounds. One of the best-known examples is chlorogenic acid, which is formed when caffeic acid is esterified with quinic acid.
Caffeic acid has demonstrated antioxidant and other biological activities in laboratory experiments, but laboratory activity should not automatically be interpreted as a health effect in people.
Human exposure also depends on the food source, chemical form, digestion, gut microorganisms, metabolism, dose, and other compounds consumed at the same time.
The Short Answer
Caffeic acid is a hydroxycinnamic acid and naturally occurring plant phenolic compound.
It can occur in free form, but much dietary caffeic acid is present as part of esters and other derivatives, including chlorogenic acids.
Fruits such as blueberries, cherries, apples, pears, grapes, and plums contain caffeic-acid-related phenolic compounds, although their amounts and chemical forms vary considerably.
On this page: What It Is | Caffeic vs. Chlorogenic Acid | Food Sources | Caffeic Acid in Fruit | Absorption & Metabolism | Research | Processing | FAQ
Compound family
Phenolic acids → Hydroxycinnamic acids → Caffeic acid
Chemical identity
3,4-dihydroxycinnamic acid.
Important distinction
Caffeic acid is not caffeine, chlorogenic acid, or CAPE.
What Is Caffeic Acid?
Caffeic acid is a naturally occurring hydroxycinnamic acid with the chemical name 3,4-dihydroxycinnamic acid.
Hydroxycinnamic acids are a family of phenolic acids commonly found in plant foods. Other members or closely related compounds include ferulic acid, p-coumaric acid, sinapic acid, and the hydroxycinnamic-acid components of chlorogenic acids.
The structure of caffeic acid contains an aromatic ring with two hydroxyl groups and a three-carbon side chain. These chemical features influence its behavior in laboratory antioxidant and redox experiments.
However, chemical structure alone does not establish what happens after a person consumes caffeic acid as part of food.
What Foods Contain Caffeic Acid?
Caffeic acid and caffeic-acid-containing derivatives are widely distributed in plant foods.
Reported dietary sources include:
- Coffee — a major dietary source of caffeic-acid-related compounds, particularly chlorogenic acids.
- Blueberries and other berries — contain caffeic acid and related hydroxycinnamic compounds as part of a larger polyphenol profile.
- Cherries — sweet and tart cherries contain caffeic-acid-related compounds, including chlorogenic and neochlorogenic acids.
- Apples and pears — important fruit sources of hydroxycinnamic acids, particularly chlorogenic-acid-related compounds.
- Plums and prunes — contain caffeoylquinic acids and other phenolic compounds.
- Grapes — contain caffeic-acid-related phenolics along with flavonoids and other polyphenols.
- Potatoes, artichokes, and eggplant — vegetable sources of hydroxycinnamic acids.
- Herbs and spices — including thyme, sage, oregano, basil, and other aromatic plants.
It is important to distinguish between free caffeic acid and caffeic acid incorporated into esters or other derivatives. Food-composition studies may measure these forms differently.
A food being listed as a source therefore does not establish a particular amount of free caffeic acid.
Caffeic Acid and Related Compounds in Fruit
For FruitFast, the most relevant context is not caffeic acid as an isolated supplement. It is caffeic acid as part of the broader phenolic chemistry of fruit.
Blueberries
Blueberries contain several hydroxycinnamic compounds in addition to anthocyanins and flavonols. Caffeic-acid-related compounds may occur alongside chlorogenic acids and other phenolics.
A result from whole-blueberry research should not automatically be attributed specifically to caffeic acid because blueberries contain many potentially active compounds.
Tart Cherries
Tart cherries contain hydroxycinnamic acids including chlorogenic and neochlorogenic acids, which are chemically related to caffeic acid.
Tart cherries also contain anthocyanins, flavonols, flavanols, and other compounds. Their overall composition should therefore not be reduced to a single phenolic acid.
Apples and Pears
Apples and pears are well-known fruit sources of chlorogenic-acid-related compounds. Digestion and metabolism of these compounds can contribute to exposure to caffeic-acid-related metabolites.
Plums and Prunes
Plums and prunes contain several hydroxycinnamic acids and caffeoylquinic acids. Their measured concentrations can differ substantially between varieties and between fresh and dried forms.
Grapes
Grapes contain multiple phenolic-acid and flavonoid families. Caffeic acid and related compounds occur within this much broader chemical mixture.
As with the other fruits discussed here, the presence of caffeic-acid-related compounds in the raw fruit does not establish their concentration in a finished juice, concentrate, dried fruit, or extract.
FruitFast context: Several fruits used by FruitFast—including tart cherries, wild blueberries, pears, grapes, plums/prunes, and others—can contain caffeic-acid-related phenolic compounds.
This does not establish the caffeic-acid concentration of a finished FruitFast juice, concentrate, dried fruit, or supplement. Quantitative finished-product claims require product-specific analytical testing.
Is Caffeic Acid an Antioxidant?
Caffeic acid demonstrates antioxidant activity in laboratory chemical systems.
Researchers have studied its ability to interact with reactive species, influence oxidation reactions, and affect lipid-oxidation processes under controlled experimental conditions.
Its two hydroxyl groups contribute to these chemical properties.
However, a strong response in a laboratory antioxidant assay does not establish that consuming caffeic acid produces the same effect throughout the human body.
After consumption, caffeic acid may be absorbed, transformed, conjugated, or metabolized by gut microorganisms. The compounds circulating in blood can therefore differ from the original molecule present in food.
Learn more about this distinction in our Antioxidants, Free Radicals & Oxidative Stress guide.
How Is Caffeic Acid Absorbed and Metabolized?
The absorption of caffeic acid depends substantially on its chemical form.
Free caffeic acid can be absorbed from the gastrointestinal tract, but much dietary caffeic acid is consumed as part of chlorogenic acids or other conjugated compounds.
Human and pharmacokinetic research shows that hydroxycinnamic acids undergo extensive metabolism after consumption.
Processes can include:
- Glucuronidation — attachment of glucuronic acid.
- Sulfation — formation of sulfate conjugates.
- Methylation — which can contribute to formation of ferulic- and isoferulic-acid-related metabolites.
- Microbial transformation — gut bacteria can convert hydroxycinnamic acids into additional metabolites, including dihydrocaffeic-acid-related compounds.
Studies after coffee consumption have detected caffeic-acid-related sulfates and glucuronides, along with ferulic, isoferulic, and dihydrocaffeic metabolites.
This means that systemic exposure after consuming a caffeic-acid-containing food is often dominated by metabolites rather than large amounts of unchanged caffeic acid.
What Role Does the Gut Microbiome Play?
The gut microbiome can contribute substantially to the metabolism of caffeic-acid-containing compounds.
Some chlorogenic acids and related phenolics escape absorption in the small intestine and reach the colon.
Colonic microorganisms can then break down and transform these compounds into smaller phenolic metabolites, which may subsequently be absorbed.
Human studies of coffee-derived chlorogenic acids have found later plasma peaks for metabolites such as dihydrocaffeic-acid conjugates, consistent with microbial metabolism in the large intestine.
Because gut microbial composition differs among people, individual exposure to caffeic-acid-related metabolites may also vary.
Caffeic Acid & Research: What Has Been Studied?
Caffeic acid has been investigated extensively in laboratory and animal research.
Researchers have studied antioxidant chemistry, inflammatory signaling, glucose-related pathways, lipid metabolism, vascular biology, neurological models, and many other biological processes.
However, direct controlled human trials using isolated caffeic acid are comparatively limited.
This distinction is important because a large preclinical literature can make the evidence appear stronger than the human evidence actually is.
Antioxidant and Oxidative-Stress Research
Laboratory experiments consistently demonstrate that caffeic acid can participate in antioxidant and redox reactions.
These studies help researchers understand its chemical behavior and possible mechanisms.
They do not establish that eating a food containing caffeic acid prevents oxidative damage or produces a particular health outcome in humans.
Inflammatory Signaling Research
Cell and animal studies have examined caffeic acid in relation to enzymes, transcription factors, cytokines, and other components of inflammatory signaling.
These are primarily mechanistic findings.
They should not be interpreted as evidence that dietary caffeic acid treats inflammation, arthritis, pain, or inflammatory disease in people.
Metabolic Research
Preclinical studies have also explored caffeic acid in glucose regulation, lipid metabolism, liver metabolism, and other metabolic pathways.
Human evidence directly involving isolated caffeic acid remains much more limited than the experimental literature.
Research using coffee, chlorogenic acids, green coffee extracts, or whole foods should also not automatically be attributed to caffeic acid alone.
Cardiovascular and Vascular Research
Caffeic acid has been studied in experimental models involving vascular function, oxidative processes, and cardiovascular signaling.
Direct evidence that dietary caffeic acid itself improves cardiovascular outcomes in humans is limited.
Findings from coffee, fruit, or other complex foods cannot isolate caffeic acid as the responsible compound unless the study design specifically does so.
How to Interpret Caffeic Acid Research
Human Research vs. Laboratory Research
For caffeic acid, this distinction is especially important.
A large portion of the literature describing “benefits” comes from:
- chemical antioxidant assays;
- cultured cells;
- animal models;
- high-dose isolated compounds;
- caffeic-acid derivatives; or
- foods and extracts containing numerous compounds in addition to caffeic acid.
These studies can provide valuable information about chemistry and biological mechanisms, but they cannot by themselves establish a benefit from consuming caffeic acid in ordinary foods.
Modern pharmacokinetic reviews also emphasize that human data remain limited for caffeic acid itself and that extensive metabolism can substantially change systemic exposure after oral consumption.
Caffeic Acid vs. Caffeic Acid Phenethyl Ester (CAPE)
Caffeic acid should not be confused with caffeic acid phenethyl ester, commonly abbreviated CAPE.
CAPE is a chemically distinct ester associated particularly with propolis and has been widely studied in laboratory and animal research.
Some articles discussing antioxidant, inflammatory, immune, or other effects actually involve CAPE rather than ordinary dietary caffeic acid.
Evidence involving CAPE should therefore not automatically be applied to caffeic acid in fruit, coffee, or other foods.
Does Processing Affect Caffeic Acid?
Yes. Food processing can change the amount and chemical form of caffeic acid and related hydroxycinnamic compounds.
Relevant factors include:
- Heat — cooking, roasting, pasteurization, and other thermal processes can alter phenolic compounds.
- Enzymatic reactions — cutting, crushing, and juicing can expose plant compounds to enzymes that influence phenolic profiles.
- Fermentation — microorganisms can release or transform caffeic-acid-related compounds.
- Drying — dehydration changes concentration on a weight basis and may also cause chemical changes.
- Storage — temperature, oxygen, light, and duration can influence phenolic composition.
- Extraction method — analytical measurements may differ depending on whether researchers measure free, conjugated, esterified, or total caffeic-acid-related compounds.
For this reason, knowing that a raw fruit contains caffeic-acid-related compounds does not establish the concentration present in a finished product.
Does Fruit Juice Concentrate Contain Caffeic Acid?
A fruit juice concentrate may contain phenolic compounds derived from the fruit used to produce it, including caffeic-acid-related compounds when those compounds are present in the starting fruit.
However, the amount in a finished concentrate depends on the fruit, cultivar, starting juice, processing conditions, concentration method, storage, and analytical definition used.
Without finished-product analytical testing, it is not appropriate to assign a specific caffeic-acid amount or describe a FruitFast concentrate as a concentrated source of caffeic acid.
This is the same distinction applied throughout the FruitFast Health Information library: the presence of a compound in a fruit does not automatically establish its amount or effect in a finished product.
Is Caffeic Acid Safe?
Caffeic-acid-related compounds occur naturally in many commonly consumed plant foods.
That does not mean every isolated dose, supplement, formulation, or derivative has the same safety profile as ordinary dietary exposure.
Human pharmacokinetic data for purified caffeic acid remain limited, particularly for high-dose or long-term use.
People considering concentrated caffeic-acid supplements should follow product directions and discuss individual questions with an appropriate healthcare professional, particularly if they are pregnant, breastfeeding, managing a medical condition, or taking medication.
Frequently Asked Questions About Caffeic Acid
What is caffeic acid?
Caffeic acid is a naturally occurring hydroxycinnamic acid and plant phenolic compound found in fruits, vegetables, coffee, herbs, grains, and other plant foods.
Does caffeic acid contain caffeine?
No. Caffeic acid and caffeine are chemically different compounds. Caffeic acid occurs in many foods that contain no caffeine.
What foods contain caffeic acid?
Caffeic-acid-related compounds are found in coffee, blueberries, cherries, apples, pears, grapes, plums, prunes, potatoes, artichokes, herbs, spices, and many other plant foods.
Is caffeic acid the same as chlorogenic acid?
No. Caffeic acid is a hydroxycinnamic acid. Chlorogenic acid is formed when caffeic acid is chemically joined to quinic acid.
Is caffeic acid an antioxidant?
Caffeic acid demonstrates antioxidant activity in laboratory chemical systems. That does not automatically establish a specific antioxidant health effect after consumption in humans.
What are caffeic acid benefits?
Caffeic acid has been studied extensively in laboratory and animal research involving antioxidant chemistry, inflammatory signaling, metabolism, and vascular biology. Direct controlled human evidence for isolated caffeic acid is much more limited, so specific health benefits have not been established simply from its presence in food.
Do blueberries contain caffeic acid?
Blueberries contain caffeic-acid-related hydroxycinnamic compounds as part of a much larger polyphenol profile. Exact amounts vary by species, cultivar, processing, storage, and analytical method.
Do tart cherries contain caffeic acid?
Tart cherries contain caffeic-acid-related compounds, including caffeoylquinic acids such as chlorogenic and neochlorogenic acids. They also contain anthocyanins, flavonols, and other phenolics.
Is caffeic acid phenethyl ester the same as caffeic acid?
No. Caffeic acid phenethyl ester, or CAPE, is a chemically distinct caffeic-acid derivative commonly associated with propolis. Research involving CAPE should not automatically be applied to dietary caffeic acid.
Is caffeic acid a phenolic acid?
Yes. Caffeic acid belongs to the hydroxycinnamic acid branch of the phenolic-acid family.
How to Evaluate Caffeic Acid Research
When reading a study about caffeic acid, first determine exactly what the researchers tested.
A study may involve:
- Free caffeic acid
- Chlorogenic acid or other caffeoylquinic acids
- Caffeic acid phenethyl ester (CAPE)
- A chemically modified caffeic-acid derivative
- Coffee or green coffee extract
- A fruit or vegetable containing many compounds
These preparations are not interchangeable.
It is also useful to ask:
- Study type — Was the experiment chemical, cellular, animal, or human?
- Form — Was caffeic acid free, esterified, conjugated, or part of a complex food?
- Dose — Was the amount similar to normal dietary exposure or a concentrated experimental dose?
- Metabolites — Did the study measure caffeic acid itself or metabolites formed after digestion?
- Other compounds — Did the preparation also contain caffeine, chlorogenic acids, flavonoids, anthocyanins, or other substances?
- Outcome — Was the study measuring antioxidant chemistry, signaling pathways, a biomarker, symptoms, or a clinical outcome?
A laboratory antioxidant result, an animal mechanism study, a change in a human metabolite, and an improvement in a clinical health outcome represent different levels of evidence.
Continue Exploring Phenolic Acids & Fruit Compounds
Caffeic acid belongs within a larger network of hydroxycinnamic acids and other naturally occurring plant compounds.
Scientific References & Sources
The following publications are provided so readers can examine the chemistry, dietary sources, absorption, metabolism, and research context discussed on this page. Findings involving one form of caffeic acid, derivative, food, extract, or experimental model should not automatically be applied to another.
1. El-Seedi HR, El-Said AMA, Khalifa SAM, et al. Biosynthesis, natural sources, dietary intake, pharmacokinetic properties, and biological activities of hydroxycinnamic acids. Journal of Agricultural and Food Chemistry. 2012;60(44):10877-10895. doi:10.1021/jf301807g. PMID: 22931195.
2. Veras KS, Fachel FNS, de Araújo BV, Teixeira HF, Koester LS. Oral Pharmacokinetics of Hydroxycinnamic Acids: An Updated Review. Pharmaceutics. 2022;14(12):2663. doi:10.3390/pharmaceutics14122663. PMID: 36559157.
3. Monteiro M, Farah A, Perrone D, Trugo LC, Donangelo C. Chlorogenic acid compounds from coffee are differentially absorbed and metabolized in humans. Journal of Nutrition. 2007;137(10):2196-2201. doi:10.1093/jn/137.10.2196. PMID: 17884997.
4. Stalmach A, Mullen W, Barron D, et al. Metabolite profiling of hydroxycinnamate derivatives in plasma and urine after the ingestion of coffee by humans: identification of biomarkers of coffee consumption. Drug Metabolism and Disposition. 2009;37(8):1749-1758. doi:10.1124/dmd.109.028019. PMID: 19460943.
5. Lafay S, Gil-Izquierdo A. Bioavailability of phenolic acids. Phytochemistry Reviews. 2008;7:301-311.
6. Vinson JA, Proch J, Bose P. Determination of quantity and quality of polyphenol antioxidants in foods and beverages. Journal of Agricultural and Food Chemistry. 2001;49(11):5315-5321.
7. Kadar NNA, Ahmad F, Teoh SL, Yahaya MF. Caffeic Acid on Metabolic Syndrome: A Review. Molecules. 2021;26(18):5490. doi:10.3390/molecules26185490. PMID: 34576959.
8. Saxena D, Badruddeen, Khan MM, et al. Pharmacokinetic challenges and novel formulation approaches for enhanced bioavailability of caffeic acid: a review. Journal of Pharmacy and Pharmacology. 2026;78(6):rgag057. doi:10.1093/jpp/rgag057. PMID: 42242712.
About This Guide
This page is provided for general educational purposes. Research involving caffeic acid, chlorogenic acids, caffeic-acid derivatives, CAPE, isolated compounds, coffee, fruit, extracts, metabolites, biomarkers, or experimental models should not be assumed to establish the same effect for other foods, products, or populations.
This information is not intended to diagnose, treat, cure, or prevent any disease and should not be interpreted as medical advice.