What it is
PEG-8 Dimethicone is a silicone polyether in which polyethylene glycol (averaging eight ethylene oxide units) is grafted onto a dimethicone backbone, giving the molecule both water-loving and silicone-loving parts. This dual nature lets it act as a nonionic emulsifier, especially for water-in-silicone systems, while also imparting a smooth, conditioning slip. It is used in sunscreens and other leave-on products to stabilize emulsions and refine application feel.
Safety & warnings
Silicone polyethers are generally well tolerated, low in irritation potential, and non-comedogenic at cosmetic use levels. As with other ethoxylated materials, the PEG portion should be sourced to control trace 1,4-dioxane. It is not a recognized fragrance allergen.
Origin & sourcing
Synthetic. It is made by attaching polyethylene glycol chains to a dimethicone (silicone) backbone.
Questions everyone asks
Is PEG-8 Dimethicone a silicone?
Yes. It is a silicone (dimethicone) modified with polyethylene glycol chains so that it can disperse in water and act as an emulsifier.
Why is it used in sunscreens?
It helps stabilize water-in-silicone emulsions and gives a smooth, light slip during application.