The ingredient, explained

Maleic Acid

A published expert safety assessment covers this exact ingredient.

Buffering

Explore connections

Ingredient guide

What it is and what it does

2-Butenedioic acid -2Z--

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

Buffering: Helps resist changes in a formula's pH.

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

Safety assessment

Panel supported maleic acid cosmetic safety specifically as a pH adjuster under described use, with low residual free acid after neutralization.

What this does not tell us

Irritation at strong/concentrated acid exposures. Conclusion is pH-adjuster-specific, not exfoliation or broad skin benefit. Local mouthrinse copolymer is distinct.

Sources for this summary. PubMed 17613135 ↗

Research review checked Oct 1, 2026

Bounded review of local candidates, exact-name indexed primary journal/PubMed safety and topical searches; not a systematic review.

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