Hy
Hydroxystearic Acid
Hydroxystearic Acid
Helps keep oil and water mixed and can help a product cleanse.
What it does
It’s a version of stearic acid, a common fatty acid, with an extra hydroxy group on its chain. It’s there to help the formula, not to change your skin.
The EU’s ingredient database lists it as an emulsifier (helps oil and water mix) and a cleanser (helps keep skin clean).European Commission, CosIng (© European Union, CC BY 4.0) · uses put in plain words by Drop ↗
The evidence, graded
expert consensusUS safety reviewers (2019) judged 102 fatty acids and their salts, hydroxystearic acid among them, safe as used in products made not to irritate or cause allergy. Two people reacted to lip products (one also to a deodorant), and patch tests pointed to hydroxystearic acid. Test antiperspirants with 7% of it irritated some of 35 people. A mouse test suggested it may cause allergy. It’s used at up to 14%, in eyeshadows.Burnett 2019 · Cosmetic Ingredient Review ↗
Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.
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