What Is Hydroxyacetophenone? Benefits for Skin Care and Cosmetic Preservation

Hydroxyacetophenone (INCI: Hydroxyacetophenone; CAS 99-93-4) is an aromatic phenolic ketone. In nature it is found in the needles of Norway spruce (piecea abies)  where is known as piceol. Plant physiologists have used HAP level as plant-stress indicators for decades,(1) indicating that the molecule role in the plant’s own oxidative-defence system.

While naturally occurring in spruce needles and cloudberries, commercial cosmetic-grade hydroxyacetophenone is manufactured from petrochemicals making it a nature identical molecule.

Multifunctional benefits of Hydroxyacetophenone in cosmetics

HAP is a truly a multifunctional with 3 key benefits:

–Antioxidant. Officially registered in the EU CosIng database as an antioxidant. Its phenolic hydroxyl group acts as an effective hydrogen donor, neutralizing reactive oxygen species (ROS) and interrupting lipid peroxidation cascades.

–Soothing and anti-irritant. Supported by peer-reviewed literature, though the strongest studies are systemic animal models rather than topical human trials.

–Preservative boosting. It acts as membrane-permeabilizing effects on microbial cells, demonstrating strong synergy when combined with traditional preservatives and antimicrobial multifunctionals.

–Emerging tyronase inhibition. A 2025 paper establish HAP as a tyrosinase inhibitor at 2% use level. This is a promising indication of its potential for reducing UV induced pigmentation applications. (2)

Popular cosmetic applications

HAP has become one of the most widely used multifunctional ingredients in modern skincare:

– Anti-Aging Serums & Creams: In an academic market survey (3) of 1,299 cosmetic products, hydroxyacetophenone was the single most frequently formulated phenolic compound in anti-aging products (present in 14.3% of antiaging formulations). It stabilizes sensitive actives against oxidation while boosting formula resilience.

-Sunscreens & After-Sun Care: Found in daily SPF and after-sun products (3.6% of surveyed after-sun lines), it calms UV-induced erythema and counteracts acute oxidative stress.

Mild & Minimalist Systems: Widely formulated in micellar cleansers, wet wipes, baby lotions, shampoos, and deodorants where gentle, non-sensitizing preservation support is critical.

Processing and incorporation techniques

• Standard Hot-Process Incorporation: Pure crystalline hydroxyacetophenone dissolves in water up to 1.0% at 22C, but to ease solubilisation at higher use levels it can be heated to 60–70 °C. It should be added to the aqueous phase during the primary heating cycle before homogenization.
• Pre-solubilized Blends: Commercial liquid composites pre-dissolve hydroxyacetophenone in carriers such as propanediol, caprylyl glycol, or 1,2-hexanediol for direct incorporation at room temperature.
• Photostability and Color Control: The phenolic hydroxyl group can oxidize and darken over time upon prolonged exposure to light, heat, or transition metal ions. Formulations should include chelating agents (e.g., sodium phytate or tetrasodium glutamate diacetate) and sacrificial antioxidants (such as tocopherol, sodium ascorbyl phosphate, or panthenol) to preserve color integrity

Typical use levels and regulatory framework

• Recommended Formulator Range: 0.1% to 1.5%
• Safety Evaluation: The Cosmetic Ingredient Review (CIR) Expert Panel concluded that hydroxyacetophenone is safe as used up to a maximum concentration of 5.0% in leave-on and rinse-off applications (3).
• Regulatory Compliance: Approved for unrestricted cosmetic use across the EU, US, China (IECIC registered), Japan, and ASEAN markets.

Where hydroxyacetophenone earns its place

Hydroxyacetophenone is a well-characterised, low-irritancy, broadly compatible phenol that stretches a preservative system, adds antioxidant capacity, supports a soothing narrative all at 0.1–1% and at modest cost. In anti-ageing, aftersun and sun care specifically, it does several jobs that would otherwise need several ingredients.

Discover Hydroxyacetophenone suppliers on the GreenChemFinder compendium