Hydroxyacetophenone
Hydroxyacetophenone
- Role
- An antioxidant that protects the formula from oxidation and is often part of its preservation system.
- Catalog formulas
- 4
- Type
- Stability
- Verified
- 09.11.2026
What does this ingredient do in an antiperspirant?
According to CosIng, it is 4-hydroxyacetophenone (CAS 99-93-4) with an antioxidant function; COSMILE Europe also lists it as a functional ingredient of fragrance oils. A 2024 review in Scientific Reports classes it among multifunctional ingredients with antimicrobial activity that manufacturers use to replace or reduce conventional preservatives.
Part of a system, not a label in isolation
In water-based roll-ons and cream deodorants it helps the formula stay stable for longer. It does not reduce sweating and does not remove body odor.
In a report published in 2026, the CIR Expert Panel concluded that hydroxyacetophenone is safe in cosmetics in the present practices of use and concentration. CosIng lists no restrictions for it, and it is not on the Annex V list of preservatives in Regulation 1223/2009: its official function is antioxidant.
Since 2018, Contact Dermatitis has published individual cases of allergic contact dermatitis to hydroxyacetophenone in facial products, including a face cream and an anti-wrinkle serum.
It is neither acetophenone nor 2-hydroxyacetophenone (CAS 118-93-4), which RIFM assesses as a separate fragrance material: the INCI name Hydroxyacetophenone in CosIng refers to 4-hydroxyacetophenone.
Products containing Hydroxyacetophenone
Links are based on the complete published INCI list for the exact product version.
Sources
The conclusions apply to the stated conditions and jurisdictions, not automatically to every concentration or product.
- EU CosIng: Hydroxyacetophenone Supports: function, substance identity, restrictions
- COSMILE Europe (CosIng data): Hydroxyacetophenone Supports: function, origin
- Chen, Chang. Deciphering trends in replacing preservatives in cosmetics (Sci Rep, 2024) Supports: use in preservation systems
- CIR: Safety Assessment of Hydroxyacetophenone as Used in Cosmetics (Int J Toxicol, 2026) Supports: function, safety assessment
- Allergic contact dermatitis caused by hydroxyacetophenone in a face cream (Contact Dermatitis, 2018) Supports: reported allergy cases
- Allergic contact dermatitis from hydroxyacetophenone in an anti-wrinkle facial serum (Contact Dermatitis, 2023) Supports: reported allergy cases
- RIFM fragrance ingredient safety assessment, 2-hydroxyacetophenone (Food Chem Toxicol, 2019) Supports: difference from a similar substance