Stearyl Alcohol
Also known as 1-Octadecanol, Octadecan-1-ol, n-Octadecanol, C18 fatty alcohol
“CIR Expert Panel says: safe as used in cosmetics.”
Stearyl alcohol (1-octadecanol, C18 straight-chain saturated fatty alcohol, CAS 112-92-5) is a widely used cosmetic emollient, co-emulsifier, and viscosity builder derived from natural fats or synthetic reduction of stearic acid. The CIR Expert Panel assessed it as safe in cosmetics (JACT 4(5):1-29, 1985), a finding confirmed without reopening in March 2004 and again per IJT 25(S2), 2006. Unlike most other C14-C22 fatty alcohols which share the 1988 group assessment, stearyl alcohol has its own individual CIR safety assessment. Published patch-test literature documents rare but confirmed cases of allergic contact dermatitis: Nishioka et al. (2022) reported seven patch-test-confirmed cases from topical medications, and Ruggiero et al. (2021) reported a case from ketoconazole cream, indicating stearyl alcohol itself — not just impurities — can act as a contact sensitiser in a subset of patients with heavy topical medication exposure.
Emollient providing skin smoothness and occlusivity in creams, lotions, and conditioners
Co-emulsifier and viscosity builder in oil-in-water emulsion systems
CIR Expert Panel found safe as used in cosmetics:1-29, 1985; confirmed 03/04, IJT 25(S2) 2006)
Long history of safe cosmetic use; practically non-toxic on dermal and oral exposure at cosmetic use levels
- · Case report of patch-test-confirmed sensitisation from stearyl alcohol in ketoconazole cream (Ruggiero et al. 2021, PMID 33759209)
- · Sensitisation risk appears higher in patients using topical medications containing stearyl alcohol than in general cosmetic users; risk in healthy populations is low
Allergic contact dermatitis confirmed by patch testing in individuals with repeated topical medication exposure; seven cases documented from ointments and antifungal creams (Nishioka et al. 2022, PMID 35174533)
CIR Quick Reference Table (12/2017, revised 07/2018) — Stearyl Alcohol row: Finding=S, Citation=JACT 4(5):1-29, 1985 confirmed 03/04 IJT …
“Stearyl Alcohol | S | | JACT 4(5):1-29, 1985 confirmed 03/04 IJT 25(S2), 2006”— QRT-122017revised072018.pdf, p. 127