What it is
Cyclohexasiloxane is dodecamethylcyclohexasiloxane (D6), a cyclic volatile methylsiloxane built from a six-unit ring of alternating silicon and oxygen atoms, each silicon carrying two methyl groups (molecular formula C12H36O6Si6). It is a light, volatile silicone that spreads easily, leaves a silky and non-greasy feel, and does not build up because it evaporates from skin rather than absorbing. These properties make it common in foundations, primers, serums, and sun-care products, where it helps with smooth application and a soft finish. In the silicone family it has emerged as a substitute for the smaller cyclic siloxanes D4 and D5.
Safety & warnings
On skin, cyclohexasiloxane is prized for a light, smooth, non-greasy feel and is generally regarded as low-irritation in topical use. Most attention to this ingredient concerns environmental persistence rather than skin reactivity: it is one of the cyclic siloxanes under regulatory review, and it gained use partly as a replacement for D4 and D5, which were restricted as persistent, bioaccumulative substances. Consumers focused on the environmental footprint of cyclic silicones may wish to factor that into their choices.
Origin & sourcing
Cyclohexasiloxane is a synthetic silicone, an organosilicon compound made from repeating silicon-oxygen units capped with methyl groups. It is a colorless liquid produced industrially as one of the cyclic volatile methylsiloxanes (cVMS) used in personal care and household products.
Questions everyone asks
What is cyclohexasiloxane used for in sunscreen?
It is a volatile silicone that acts as a lightweight emollient and solvent. It helps the product spread smoothly and feel silky and non-greasy, then largely evaporates without leaving residue or buildup.
Is cyclohexasiloxane the same as D4 or D5?
No. It is D6, the six-unit cyclic siloxane, a larger relative of D4 and D5. It is often used as a substitute for those smaller cyclic siloxanes, which face restrictions for environmental persistence.
Does cyclohexasiloxane clog pores?
It is a volatile silicone that evaporates rather than absorbing or building up, and it leaves no oily residue. Tolerance varies by individual, but it is generally chosen for a light, non-greasy finish.