What is it?
A fatty alcohol with an 18-carbon chain, sold as a waxy solid. Despite the name, it is not a drying alcohol like ethanol. In creams and lotions it softens skin, thickens and stabilizes emulsions and leaves a non-greasy film that helps skin hold moisture. It also makes shampoos and bubble baths opaque and is used in ointments and other medicines.
Key information
- The CIR Expert Panel concluded in 1985 that stearyl alcohol is safe as currently used in cosmetics, and later reaffirmed that conclusion.
- It is a fatty alcohol, not a drying alcohol like ethanol.
- Synthetic stearyl alcohol is approved in the U.S. as a direct food additive.
- Allergic reactions are uncommon in patch-test screening of dermatitis patients.
More information
Stearyl alcohol is a mixture of solid fatty alcohols that is at least 90 percent n-octadecanol. The CIR describes two production routes: the Ziegler process, which builds the chain from ethylene, and high-pressure catalytic hydrogenation of stearic acid. It is one of the two main components of cetearyl alcohol, which we rate Green Light.
The Cosmetic Ingredient Review (CIR) Expert Panel concluded in 1985 that stearyl alcohol is safe as currently used in cosmetics, and later reaffirmed that conclusion. The review found a very low order of toxicity when swallowed, minimal to mild skin irritation in rabbits, and a very low potential for irritation and allergy in clinical patch tests. In 1981 it was reported in 425 cosmetic formulas at up to 50 percent, though very few products used the highest levels. Synthetic stearyl alcohol is approved as a direct food additive in the U.S., and it is an ingredient in over-the-counter external drug products.
Allergy is uncommon. In yearly screening by the North American Contact Dermatitis Group with 30 percent stearyl alcohol, about 0.2 to 1.2 percent of the patients tested each year had allergic reactions, and another study found 4 reactions among 1,664 patients. Data on pore clogging are mixed: stearyl alcohol was not comedogenic in a small rabbit-ear test reviewed by the CIR, while a 1989 rabbit-ear survey, a very sensitive test, scored it 2 of 5.
On labels, stearyl alcohol is not a sign of a drying alcohol. If you want to avoid ethanol, look for “alcohol” or “alcohol denat.” instead.
Sources: Journal of the American College of Toxicology (1985), via Cosmetic Ingredient Review: Final report on the safety assessment of stearyl alcohol, oleyl alcohol and octyl dodecanol; Cosmetic Ingredient Review: Quick reference table of safety conclusions (September 2022); Journal of the Society of Cosmetic Chemists (1989): Comedogenicity and irritancy of commonly used ingredients in skin care products
