Ceteareth-20
Also known as Ethoxylated cetearyl alcohol (20 EO), Polyoxyethylene (20) cetearyl ether, Cetearyl alcohol ethoxylate
“CIR Expert Panel says: safe as used in cosmetics.”
CETEARETH-20 is a nonionic ethoxylated emulsifier formed by reacting cetearyl alcohol (a mixture of cetyl C16 and stearyl C18 fatty alcohols) with approximately 20 ethylene oxide units, yielding a polyoxyethylene ether with an HLB of approximately 15.7. It functions as a primary O/W emulsifier in creams and lotions at typical concentrations of 1–5%. The CIR Expert Panel originally assessed Ceteareths (the full ethoxylate series) in 1999 (IJT 18(S3):41-49) and issued an amended assessment in 2012 (IJT 31(S2):169-244), finding all assessed Ceteareths — including Ceteareth-20 — to be safe as used when formulated to be non-irritating (QRT Finding=SQ). The non-irritating formulation qualification is standard for nonionic surfactant emulsifiers. The principal safety concern for all ethoxylated ingredients is trace 1,4-dioxane contamination arising from the ethoxylation manufacturing process; a 2005 safety review of PEGs and their derivatives (Fruijtier-Pölloth, PMID 16011869), which explicitly covers ceteareths as a PEG ether class, confirms that 1,4-dioxane and ethylene oxide are byproducts requiring removal and recommends continued manufacturer effort to eliminate these impurities.
Effective O/W emulsifier (HLB ~15.7): creates stable, fine-droplet emulsions in creams and lotions at typical 1–5% use levels
Non-ionic character provides broad compatibility with anionic, cationic, and amphoteric co-ingredients
CIR Expert Panel assessed Ceteareth-20 as safe as used (Finding=SQ), with the 2012 amended assessment reaffirming the original 1999 conclusion
- · CIR SQ qualification: formulation must be non-irritating; as a surfactant/emulsifier, Ceteareth-20 can disrupt barrier function at high concentrations or in sensitive individuals.
1,4-Dioxane is an unavoidable trace byproduct of the ethoxylation process used to manufacture Ceteareth-20; it is not listed on the label. Vacuum stripping during manufacturing is the standard control (Fruijtier-Pölloth 2005, PMID 16011869).
CIR Quick Reference Table (12/2017, revised 07/2018) — Ceteareth-20 row: Finding=SQ, Detail='Safe as used in cosmetics when formulated to…
“Ceteareth-20 | SQ | Safe as used in cosmetics when formulated to be non- irritating | IJT 18(S3):41-49, 1999; IJT 31(S2):169-244 (2012)”— QRT-122017revised072018.pdf, p. 23