Dimethicone in its simplest form is polydimethylsiloxane, also known as silicone oil, but more commonly called dimethicone. Silicone oils are derived from silica (sand and quartz are silicas).
Dimethicone comes in various viscosities, this one is 350 centistokes, a medium viscosity which offers excellent barrier properties when used in skin protectant formulations. It adds slip and glide, reducing tackiness. It offers conditioning properties when used in hair and skin care applications.
Used at a rate of 1% to 30%, dimethicone conforms to the FDA's Tentative Final Monograph on OTC Skin Protectants. However, provided you make no drug claims for it, dimethicone does not have to be declared as an active ingredient, nor does your product or facility need to conform to OTC drug production standards. Dimethicone can be added to any cosmetic and declared on the ingredient label in descending order.
When using dimethicone in cosmetic formulations, one should be guided by the usage rates in the Cosmetic Ingredient Review (CIR) tables (see our Reference Room for links to these PDFs) as these apply to cosmetics rather than OTC products.
The CIR lists Dimethicone in the Cosmetic Ingredients Found Safe as Used in the following amounts:
Appearance: Semi viscous clear liquid
Stored somewhere cool, dark, and dry, Dimethicone 350 has a long shelf life.