Cetearyl Alcohol
Also known as Cetostearyl alcohol, Cetyl/stearyl alcohol, C16-C18 fatty alcohol, Cetearyl alcohol (NF)
“CIR Expert Panel says: safe as used in cosmetics.”
Cetearyl alcohol is a long-chain fatty alcohol mixture (C16 cetyl + C18 stearyl, typically 65-80% stearyl / 20-35% cetyl in technical grade) used as an emollient and emulsion stabiliser. The 1988 CIR Expert Panel concluded it 'safe as cosmetic ingredients in the present practices of use' (J Am Coll Toxicol 7(3):359-413), a verdict reaffirmed by the CIR in December 2005 without reopening the assessment. Patch-test sensitization is uncommon in the general eczema population (approximately 0.8% positive at 20% cetylstearyl alcohol per Hannuksela 1988), but documented allergic contact dermatitis cases cluster in patients with stasis eczema, leg ulcers, or heavy topical-medicament exposure (Rademaker 1997; Nishioka 2022); Hannuksela suggested impurities in commercial-grade material may drive the observed reactivity rather than the pure fatty alcohols themselves.
Primary function as an emollient providing smoothness and hydration in creams and lotions
Emulsion stabiliser and viscosity controller in oil-in-water cosmetic emulsions
Long history of safe use since 1913 (cetyl alcohol first isolated by Chevreul) with practical nontoxicity on oral exposure (LD50 > 5 g/kg in rats)
No human sensitization observed in a 3.0% cream formulation tested on human subjects (CIR 1988)
- · Allergic contact dermatitis in sensitised individuals, particularly in patients with stasis eczema, leg ulcers, or heavy topical-medicament exposure (Rademaker 1997; Nishioka 2022)
- · Approximately 0.8% positive patch-test rate in eczema populations at 20% cetylstearyl alcohol (Hannuksela 1988)
- · Mild skin irritation observed in rabbits at 3.0% cream formulations (CIR 1988 animal data)
Sensitization may be driven by impurities in commercial-grade material (hydrocarbons 0.1-1.4%, odd-chain alcohols 1-3.5%, branched-chain primary alcohols 0.2-2%) rather than by pure cetyl or stearyl alcohol (Hannuksela 1988; CIR 1988 page 363)
CIR Final Report on the Safety Assessment of Cetearyl Alcohol, Cetyl Alcohol, Isostearyl Alcohol, Myristyl Alcohol, and Behenyl Alcohol (…
CIR Quick Reference Table (12/2017, revised 07/2018) - Cetearyl Alcohol row: Finding 'S' (Safe), Citation 'JACT 7(3):359-413, 1988 confir…
“Cetearyl Alcohol | S | [no detail column entry] | JACT 7(3):359-413, 1988 confirmed 12/05”— QRT-122017revised072018.pdf, p. 23