What it is
PEG/PPG-9/2 dimethyl ether is a copolymer of ethylene oxide and propylene oxide capped with methyl ether groups, forming a water-soluble liquid. It works as a humectant and as a solvent or co-solvent that keeps ingredients in solution and helps create a light, non-tacky texture. In sunscreens it is valued for giving a fresh, smooth skin-feel and for helping disperse other components evenly.
Safety & warnings
This polyether is generally well tolerated on intact skin and has a low irritation profile at cosmetic use levels. It is not a known fragrance allergen and is not regarded as comedogenic. As with other PEG/PPG materials, cosmetic grades are purified to limit trace impurities from manufacturing.
Origin & sourcing
Synthetic; produced by copolymerizing ethylene oxide and propylene oxide and then capping the ends with methyl ether groups.
Questions everyone asks
Why is PEG/PPG-9/2 dimethyl ether used in sunscreens?
It acts as a humectant and solvent that helps keep the formula uniform while contributing a light, fresh, non-sticky skin feel.
Does it provide sun protection?
No. It is a texture and moisture ingredient and does not absorb or block UV light.