Some of the most commonly used silicone substances, called cyclosiloxanes, are:
Octamethylcyclotetrasiloxane (D4) is an odorless, colorless non-oily volatile silicone fluid used primarily to make other silicone materials. During this manufacturing process, virtually all of the material is consumed, with only a tiny amount of D4 remaining. In a small handful of personal care products, D4 can be used as an additive, providing certain application-related benefits preferred by consumers.
Decamethylcyclopentasiloxane (D5) is an odorless, colorless non-oily volatile siloxane fluid used primarily to make other silicone materials. It is also used as an ingredient in personal care and consumer products and in dry cleaning. In personal care products, D5 acts as a "carrier," allowing products to spread smoothly and easily, providing a silky, luxurious feel during application. In dry cleaning, D5 carries detergent to clothes and rinses away suspended dirt and oils trapped by the detergent. It does not interact with textiles and therefore, helps maintain the quality and color of clothes that are dry cleaned.
Dodecamethylcyclohexasiloxane (D6) is a clear, odorless, siloxane fluid that is used in some applications including cosmetics, where it provides certain application-related benefits preferred by customers.