What is it?
A synthetic wax made to match the composition and properties of spermaceti, a waxy substance found in the heads of sperm whales. It is a blend of esters formed from fatty acids and fatty alcohols that each have 14 to 18 carbons, such as cetyl palmitate and myristyl myristate. It softens skin and adds body to creams, lotions, lipsticks, makeup and hair conditioners.
Key information
- The CIR Expert Panel concluded in 1997 that cetyl esters is safe as used, and in 2013 included it among alkyl esters that are safe when formulated to be non-irritating.
- In 2013 it was reported in 476 cosmetic products, at up to 30 percent.
- A product containing 60 to 65 percent cetyl esters did not irritate rabbit skin or eyes.
- It scored 1 out of 5 in a 1989 rabbit-ear comedogenicity survey, a grade the author did not consider significant.
More information
Sperm whales are named after spermaceti, the waxy substance in their heads, which was once used in oil lamps, lubricants and candles. Commercial whaling from 1800 to 1987 greatly reduced their numbers, and they are listed as endangered. Cetyl esters is a synthetic wax intended to be indistinguishable from natural spermaceti. According to the CIR, commercial cetyl esters contains one or more of six esters: cetyl palmitate, cetyl stearate, cetyl myristate, myristyl myristate, myristyl stearate and stearyl stearate. It is also defined in the National Formulary, a U.S. compendium for pharmaceutical ingredients.
The Cosmetic Ingredient Review (CIR) Expert Panel concluded in 1997 that cetyl esters is safe as used in cosmetics. It relied largely on earlier reviews of its component esters, whose data showed no systemic toxicity, no sensitization or photosensitization, and little irritation. A product containing 60 to 65 percent cetyl esters caused no irritation on intact or abraded rabbit skin and no eye irritation, and the same product’s lethal oral dose in mice was more than 20 g per kilogram. In 2013 the panel folded cetyl esters into a review of 237 alkyl esters, which it concluded are safe as used when formulated to be non-irritating. Cetyl esters was then reported in 476 products, at up to 30 percent.
Pore clogging does not appear to be a concern. In a 1989 survey that used the sensitive inner ear of rabbits, cetyl ester NF scored 1 out of 5 for comedogenicity and 1 for irritation, grades the author did not consider significant, and he wrote that large esters such as cetyl palmitate “are not a problem.”
On labels it appears as cetyl esters. Despite the history of the name, it is synthetic and does not come from whales.
Sources: International Journal of Toxicology (1997), via Cosmetic Ingredient Review: Final report on the safety assessment of cetyl esters (in the 2012 alkyl esters re-review supplement); Cosmetic Ingredient Review: Amended safety assessment of alkyl esters as used in cosmetics (2013); Journal of the Society of Cosmetic Chemists (1989): Comedogenicity and irritancy of commonly used ingredients in skin care products; NOAA Fisheries: Sperm whale
