What it is
This is a volatile silicone consisting of cyclic dimethylsiloxane units, historically supplied as a mixture of ring sizes. It spreads easily, imparts a silky, non-greasy slip, and then evaporates, which makes it a useful carrier for other ingredients and a way to improve application feel. In sunscreens and makeup it helps the product glide on smoothly and reduces tackiness.
Safety & warnings
Cyclomethicone is generally well tolerated and largely evaporates from the skin after application. It is not associated with comedogenicity and is not a recognized fragrance allergen. Some cyclic silicones have been the subject of environmental review, which has shifted many formulas toward specific or alternative materials.
Origin & sourcing
Synthetic; a volatile cyclic silicone produced industrially from silicon-based feedstocks.
Questions everyone asks
What does cyclomethicone do in sunscreen?
It is a volatile silicone that gives a light, smooth slip and acts as a carrier, then evaporates so the product does not feel greasy.
Does cyclomethicone stay on the skin?
No. It is volatile and largely evaporates after application, leaving behind the non-volatile ingredients it helped spread.