The ingredient, explained

Hydroxyphenoxy Propionic Acid

Research examined HYDROXYPHENOXY PROPIONIC ACID under the stated study conditions.

Skin conditioning

Explore connections

Ingredient guide

What it is and what it does

-R--2--4-hydroxyphenoxy-propanoic 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 research on a combination

The multi-ingredient formula improved measured facial pigmentation alongside the prescription combination; tolerability favored the cosmetic formula.

What this does not tell us

82 subjects, 12 weeks, investigator-blinded and no verified random allocation or vehicle arm. Ellagic acid, yeast extract and salicylic acid were co-actives. Reported parity does not establish formal equivalence or isolated ingredient benefit.

Sources for this summary. PubMed 24305422 ↗

Research review checked Oct 1, 2026

Review supplied candidate titles and available abstracts selectively for exact identity; targeted primary PubMed/publisher searches. This is not an exhaustive systematic review.