Cyclomethicone is used as a base solvent to blend with fragrance oils and perfume oils. Cyclomethicone is a clear, odorless silicone. It leaves a silky-smooth feel when sprayed on the skin. Ideal for body sprays, lotions creams, bath salts, hair care, linen sprays etc. Cyclomethicone stays completely blended and crystal clear without shaking.

Cyclomethicones are unmodified silicones that possess a cyclical structure rather than the chain structures of dimethyl silicones. Low heat of vaporization and the ability to select a desired vapor pressure has led their use as cosmetic vehicles. Unmodified silicones stay on or near the surface of the skin. Not only are the molecules too big to physically enter past the upper living cells, they associate with the upper layer of drying skin but they also cannot penetrate cell membranes due to their large size.

Cyclomethicones evaporate quickly after helping to carry oils into the top layer of epidermis. From there, they may be absorbed by the skin. Cyclomethicones perform a similar function in hair care products by helping nutrients enter the hair shaft.

Formal Chemical Name (IUPAC)
2,2,4,4,6,6,8,8,10,10-decamethyl-1,3,5,7,9,2,4,6,8,10-pentaoxapentasilecane

References

http://www.dowcorning.com/