Polyquaternium-28

Polyquaternium-28 is a synthetic polymer — a long-chain molecule composed of repeating units with a positive electrical charge. It is derived from quaternised (charged) cellulose or similar polysaccharide backbones and is used primarily in hair and personal care formulations.In skincare products, it functions as a film-forming and conditioning agent. It deposits onto the skin surface, where its charged structure allows it to bind temporarily to the negatively charged outer layers. This creates a thin, smooth protective layer.

Polyquaternium-28 works through electrostatic attraction. Its positive charge allows it to adhere to the negatively charged keratin proteins on the skin surface. Once bound, it forms a thin polymer film that smooths the outer layer, reducing roughness and scattering of light.This film is temporary and washes away with cleansing; it does not penetrate the epidermis or alter skin biochemistry. The effect is purely cosmetic and mechanical.

Polyquaternium-28 is typically incorporated into moisturisers, serums, or lightweight conditioners at low concentrations. Apply to damp or clean skin as part of your regular routine. It works well layered under or within hydrating products, and poses no interaction concerns with other skincare ingredients. If you have very sensitive skin, patch test first, as some individuals may react to film-forming polymers.

Polyquaternium-28 is generally well-tolerated and approved for use in cosmetics across major regulatory bodies including the EU and UK. It is non-toxic and non-irritating at typical use levels. Some individuals with very reactive skin may experience mild irritation or prefer to avoid polymer-heavy formulations.