Polypropylsilsesquioxane

Polypropylsilsesquioxane is a synthetic silicone polymer derived from silica. It belongs to the silsesquioxane family of ingredients and is used primarily in cosmetics for its film-forming properties.When applied to skin, it forms a thin, continuous layer that sits on the surface. This film is designed to improve the feel and appearance of products whilst creating a light protective barrier. It is used in roughly 0.5% of skincare formulations.

Polypropylsilsesquioxane works by polymerising on the skin surface to form a cohesive, lightweight film. Unlike heavier silicones, this polymer is designed to be breathable whilst still providing a protective layer.The film smooths micro-irregularities on skin, which can optically reduce the visibility of texture and fine lines. It also slows moisture evaporation from the stratum corneum without fully sealing the skin, making it suitable for use on most skin types.

Polypropylsilsesquioxane is typically found in primers, serums, and lightweight moisturisers. Apply over clean skin or after other actives to allow the film to set. It can be layered under makeup or used alone. Remove with a gentle cleanser in the evening, as the film should not be left on skin overnight.

Polypropylsilsesquioxane is generally well-tolerated and non-comedogenic in most formulations. It is not known to trigger sensitivity or allergic reactions in the general population, though individuals with silicone sensitivities should patch-test first.