Hydroxyacetophenone

How concerned to be

The major review that exists lands on 'safe as currently used,' not 'hazard-free.' The U.S. Cosmetic Ingredient Review (CIR) Expert Panel evaluated Hydroxyacetophenone in its September 2022 final report and concluded it is safe in cosmetics in the present practices of use and concentration described in the assessment — reported use concentrations range up to 0.23% in eye-area products, up to 0.6% in products that could contact mucous membranes, and up to 5% in leave-on night creams, paste masks, and mud packs. The Panel cited a favorable overall toxicological profile: negative results across genotoxicity assays (bacterial reverse mutation, mouse lymphoma, sister chromatid exchange, in vitro cell transformation, and an in vivo micronucleus assay), no carcinogenicity red flags, and a GLP-adjacent OECD TG 422 reproductive/developmental screening study (oral doses of 0, 40, 150, and 600 mg/kg bw/day in rats) that found no toxicologically significant parental or offspring effects, with a NOAEL of 600 mg/kg bw/day. Dermal irritation and sensitization testing was consistently negative, including at the 5% maximum reported use concentration. Set against that favorable profile: the ingredient was rated a severe eye irritant in rabbit testing, and it carries a real H302 acute-oral-toxicity classification on supplier SDS documentation. Sensitization risk looks low based on the controlled testing available, but the existence of one clinical case report of an allergic reaction to it (in a leave-on facial product) means it isn't zero, and a formal pediatric-specific safety assessment doesn't exist. Net: reasonable to accept in a rinse-off wipe formula at typical low percentages; worth more caution in any product intended for use very near a baby's eyes, and worth a second look if a baby shows any skin reaction to a product containing it.