What it is
This ingredient is formed by adding average chains of about eight ethylene oxide, five propylene oxide, and three butylene oxide units onto a glycerin core, creating a water-soluble polyether. The mixed-oxide structure gives it humectant properties that help draw and hold moisture while leaving a smooth, non-tacky finish. In gel and emulsion sunscreens it conditions the skin and can aid the even distribution of other ingredients.
Safety & warnings
This polyether is generally well tolerated in leave-on products. As with other alkoxylated ingredients, manufacturers control for residual ethylene oxide and 1,4-dioxane through purification. It is not a known fragrance allergen and is not considered comedogenic at typical use levels.
Origin & sourcing
Synthetic, produced by reacting glycerin with ethylene oxide, propylene oxide, and butylene oxide.
Questions everyone asks
What is the role of this ingredient in skincare?
It acts mainly as a humectant and conditioning agent, helping the formula hold moisture and feel smooth without stickiness.
What do the numbers 8/5/3 mean?
They indicate the average number of ethylene oxide, propylene oxide, and butylene oxide units added to the glycerin backbone.