Cyclopentasiloxane.

What it does

It spreads ingredients into a light, silky, non-greasy layer and then evaporates off the skin or hair within minutes, leaving little to no residue. It is widely used as a carrier solvent and to give products that smooth, fast 'slip' feel, and is often paired with non-volatile dimethicone so the dimethicone is left behind as a thin film once the D5 flashes off.

Benefits

• Immediate silky, dry, non-greasy slip that helps other ingredients spread evenly
• Volatile, so it evaporates and does not leave a heavy or tacky residue
• Excellent carrier/solvent that thins out heavier silicones and oils
• Helps deliver and 'set down' longer-lasting actives like dimethicone on the surface

Side effects

• Very low irritancy; tolerated by most skin and hair
• An environmental rather than a skin concern: D5 is persistent and bioaccumulative, and the EU limits it to 0.1% in rinse-off (wash-off) cosmetics from 2020

Who it's for

Most skin and hair types; popular in primers, hair serums, sunscreens and makeup for a light, fast-absorbing feel

Who should be careful

No notable skin contraindication; those minimising environmental silicone load may prefer to limit rinse-off products containing it

• Decamethylcyclopentasiloxane (D5) - Wikipediaencyclopedia
• Cyclopentasiloxane (Explained + Products)cosmetic database

Researched & reviewed · July 2, 2026