Quick answer
Waxy compound that is a derivative of the fatty alcohol stearyl alcohol ; Functions as a surfactant and solubilizing agent ; Helps keep ingredients together in an emulsion ; Deemed safe by the independent Cosmetic Ingredient Review panel
Steareth-21
Updated
Poly(oxy-1,2-ethanediyl), .alpha.-octadecyl-.omega.-hydroxy
Purpose
Fatty alcohol-derived surfactant, emulsifier, and stabilizing ingredient that’s been ruled safe as it is used in cosmetics.
Rating
GOOD
Category
Emulsifier
INCI Purpose
CLEANSING, SURFACTANT - CLEANSING, SURFACTANT - EMULSIFYING
Alternative Names
At a Glance
Waxy compound that is a derivative of the fatty alcohol stearyl alcohol
Functions as a surfactant and solubilizing agent
Helps keep ingredients together in an emulsion
Deemed safe by the independent Cosmetic Ingredient Review panel
Article
Steareth-21 is a waxy compound that functions as a surfactant, emulsifier and solubilizing agent, all of which helps create optimal aesthetics for skin care formulations. Steareth-21 is often combined with other steareth ingredients, such as steareth-2, for an improved sensory profile.
Steareth ingredients are prepared by interacting with the chemical intermediate gas ethylene oxide with stearyl alcohol, a process which forms an entirely new stable compound. The number that comes after (for instance, 21) indicates the average number of ethylene oxide units used in the preparation.
In 2012, the independent Cosmetic Ingredient Review panel ruled that steareth-21 is safe as used in cosmetics in amounts up to 7%. There have been concerns about the safety of steareth ingredients because toxic 1,4-dioxane, a by-product of ethoxylation, can be produced; however, this is eliminated through purification processes.
See: Emulsifier
References