The ingredient, explained

Hydroxycinnamic Acid

Research examined HYDROXYCINNAMIC ACID under the stated study conditions.

Skin conditioning

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Ingredient guide

What it is and what it does

4-Hydroxycinnamic acid; 4-Coumaric acid

About this ingredient: EU CosIng ingredient registry (via Open Beauty Facts taxonomy) ↗

Skin conditioning: A broad cosmetic role for maintaining skin condition. It does not identify a particular clinical benefit.

Function definitions: European Commission ingredient function definitions (SCCNFP/0299/00, pages 16 to 20) ↗

Registry functions describe possible formulation roles, not results for a finished product. A dictionary entry is not an approval or a safety assessment.

A closer look

What the research shows

Human topical research

Para-hydroxycinnamic acid formulations reduced UV-induced erythema and selected barrier/inflammatory measurements in three controlled studies.

What this does not tell us

Two-week pretreatment and experimental UV challenge, not long-term aging outcomes. Sample and randomization are not established in the abstract; some formulas also contain niacinamide.

Sources for this summary. PubMed 39138602 ↗

Research review checked Oct 1, 2026

Read exact local candidate abstracts first; select identity-relevant papers; targeted primary PubMed/publisher searches. This is not an exhaustive systematic review.

Ingredient research is not proof that a product containing this ingredient works.