Polyisobutene is a polymer of the hydrocarbon isobutylene. It functions as a texture-enhancing, thickening and film-forming agent. It is a synthetic liquid that offers emollient benefits and is often used to replaced mineral and silicone oils in formulations. In our formulas, polyisobutene is part of a proprietary thickener-emulsifier and combines with polyacrylate-13 and polysorbate 20 to create supple, silicone-like textures without the use of silicones. Polyisobutene works by increasing the thickness of the lipids or oils in product formulations. It acts as a lubricant on the skin and is often used as a substitute for squalene.