Dimethicone

Dimethicone, also known as polydimethylsiloxane (PDMS), is a silicone-based polymer widely used in cosmetics, personal care products, and medicine. It is a linear siloxane made up of repeating dimethylsiloxane units. Dimethicones vary in viscosity, from light, volatile fluids to thicker oils, and are typically colorless, odorless, chemically inert, and thermally stable.

In cosmetic and personal care formulations, dimethicone serves as an emollient, slip agent, and barrier. It conditions the skin and hair by forming a protective film that reduces transepidermal water loss and enhances product spreadability. Volatile dimethicone helps create a lightweight feel as it evaporates after application, while nonvolatile forms remain on the surface to provide longer-lasting protection and conditioning.

Medical and consumer health uses include skin protectants that form a barrier on damaged or sensitive skin, used in diaper rash creams and other barrier products. Dimethicone is also found in some ophthalmic and ear care products as a lubricating agent or to aid in softening earwax.

Safety and regulation: Dimethicone is generally regarded as safe for topical use and is considered non-irritating and non-sensitizing for most people. Systemic absorption from topical products is minimal. Some individuals with acne-prone skin report pore occlusion with occlusive formulations, depending on concentration and vehicle. Dimethicone should not be ingested, and products should be used according to labeling.

Additional notes: Dimethicone’s inert nature and versatility contribute to its widespread use across many cosmetic and therapeutic applications.