The ingredient, explained

Mandelic Acid

An exfoliating acid studied as a high-strength peel for facial acne.

AHA exfoliantAntimicrobial

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Ingredient guide

What it is and what it does

Benzeneacetic acid, .alpha.-hydroxy-

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

AHA exfoliant: Alpha hydroxy acid category. Exfoliation depends on the acid, concentration, pH and the rest of the formula; an AHA may also be used to control pH.
Antimicrobial: A technical role associated with controlling microorganisms on skin.

Function definitions: FDA: Alpha hydroxy acids ↗ · 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

A 50-patient randomised trial compared six sessions of 45% mandelic acid and 30% salicylic acid peels over 12 weeks. Overall acne-score improvement did not differ significantly, while mandelic acid had fewer adverse effects and performed better on inflammatory lesions.

What this does not tell us

The trial had an active comparator rather than a vehicle and examined repeated peel procedures. It does not establish the results of a lower-strength daily mandelic acid product.

Sources for this summary. PubMed 31553119 ↗

Research review checked Sep 30, 2026

Selected primary sources were reviewed for the existing research brief on 30 September 2026, with exact ingredient, route and combination limitations recorded. This was a bounded editorial review, not a systematic search.