What it is
Simethicone is a defined mixture of fully methylated linear siloxane polymers (dimethicone) and silicon dioxide. In personal care formulations it imparts a smooth, conditioned skin feel and can act as an anti-foaming agent during manufacturing and use. In sunscreens it contributes to a silky texture and an even, spreadable film.
Safety & warnings
Simethicone is considered well tolerated and non-irritating in topical use, with a long record of use in both cosmetics and other consumer products. It is not a known fragrance allergen and is not associated with notable comedogenicity at typical use levels.
Origin & sourcing
Synthetic; manufactured by combining silicone polymer (dimethicone) with finely divided silica.
Questions everyone asks
How is simethicone different from dimethicone?
Simethicone is dimethicone blended with silica, which gives it added anti-foaming behavior; plain dimethicone is the silicone polymer alone.
Why is it in sunscreen?
It helps create a smooth, even, conditioned feel and can reduce foaming, supporting a pleasant texture and uniform film.