Hydroxyacetophenone

Irritancy: unknownComedogenicity: unknownAntioxidant

The details

Hydroxyacetophenone is a small phenolic molecule that earns its place in a formulas as an antioxidant and preservative booster. As a phenol, it is able to neutralize free radicals to protect both the product and the skin from oxidative stress. Though it can't kill microbes on its own, it works as a good supporting agent when combined with other preservatives like Phenoxyethanol or 1,2-Hexanediol . This ingredient naturally occurs as piceol in Norwegian spruce needles (~0.4-1.1% dry weight and in cloudberries). Though the cosmetic-grade material is synthesized for purity and consistency. You'll usually see it used at low levels and suppliers recommend up to 1% added to a water phase. Safety testing was done at concentrations like 0.05% in SPF products and 0.5% in a Human Repeated Insult Patch Test. The safety evidence is assuring; this ingredient is safe for cosmetics in current use and also holds safety status as a food flavoring as well. An honest caveat: the "soothing" and "anti-inflammatory" claims come mostly from supplier marketing rather than published clinical trials. The Cosmetic Ingredient Review's own literature search found no useful efficacy studies on this ingredient. So the antioxidant and preservative-boosting roles are the well supported ones while the calming benefit is plausible but thinly evidenced. Overall, this is a well-tolerated, low-irritation multitasker that quietly helps a formula stay fresh and stable.