What it is
PEG/PPG-20/15 Dimethicone is a dimethicone backbone modified with polyethylene glycol and polypropylene glycol side chains, giving the molecule both oil-loving and water-loving regions. This amphiphilic structure lets it emulsify oil and water phases and stabilize water-in-silicone or water-in-oil systems common in fluid sunscreens. It also contributes a light, slippery skin feel and helps disperse pigments and UV filters evenly.
Safety & warnings
Silicone polyether emulsifiers of this type are generally well tolerated and non-sensitizing at use levels. They are not associated with notable comedogenicity. As with any surfactant, very high concentrations could be mildly irritating to compromised skin, but this is uncommon in finished products.
Origin & sourcing
Synthetic; manufactured by attaching polyether (PEG and PPG) chains to a silicone (dimethicone) polymer.
Questions everyone asks
What does PEG/PPG-20/15 Dimethicone do in a sunscreen?
It works as an emulsifier and surfactant, holding the oil and water phases together and helping the product spread smoothly while dispersing UV filters and pigments evenly.
Is PEG/PPG-20/15 Dimethicone a silicone?
Yes. It is a dimethicone silicone modified with polyether chains, which makes it water-dispersible and able to act as an emulsifier rather than a simple silicone oil.