Hydrogenated Polyisobutene is a synthetic emollient and skin-conditioning ingredient used in skincare, lip care, makeup, and sunscreen formulas. It is made by polymerizing isobutene, then hydrogenating and purifying the material to create a clear, stable, oil-like ingredient with a smooth, cushiony feel. Its INCI name is Hydrogenated Polyisobutene, and commonly referenced CAS numbers include 68937-10-0, 40921-86-6, and 61693-08-1, depending on grade and supplier documentation.

In skincare, Hydrogenated Polyisobutene helps soften the skin, improve slip, and reduce moisture loss by forming a lightweight, flexible film on the surface. It is often used as an alternative to mineral oil or certain silicone ingredients because it gives formulas a silky feel without feeling overly heavy. In lip products, it can add shine, glide, and longer wear. In creams, balms, masks, and color cosmetics, it can improve texture, spreadability, and product stability.

Hydrogenated Polyisobutene does not exfoliate, brighten, or act like an active treatment ingredient. Its role is mostly sensory and supportive. It helps a formula feel smoother, apply more evenly, and leave skin feeling soft and conditioned. Because it is hydrophobic, meaning it does not mix with water, it can also help improve water resistance in certain formulas.

Overall, Hydrogenated Polyisobutene is best described as a functional emollient. It supports comfort, softness, and moisture retention while helping formulas feel more elegant on the skin.