Chitosan

Chitosan is a natural biopolymer derived from chitin, found in shellfish exoskeletons and fungal cell walls. It is a degradable polysaccharide that has been modified and adapted for cosmetic use, where it functions primarily as a film-forming agent and hair fixative.In skincare formulations, chitosan creates a protective layer on the skin surface. Its film-forming properties help to condition and provide a smooth texture, whilst its biocompatibility makes it suitable for sensitive formulations.

Chitosan works by forming a thin, breathable film across the skin surface. This physical barrier helps to smooth irregularities and create a refined appearance whilst allowing normal skin function to continue. The film-forming action is its primary cosmetic mechanism in skincare products.Research also suggests chitosan may interact with skin cells in ways that support antimicrobial and anti-inflammatory responses. However, most detailed mechanisms observed in research relate to specialised formulations (such as wound-healing scaffolds) rather than everyday cosmetic concentrations, so transl…

Chitosan works best in leave-on formulations where its film-forming properties can develop on the skin surface. It is commonly found in serums, lightweight moisturisers, and conditioning treatments. Apply to clean skin and allow a moment for the protective layer to set before applying additional products. It pairs well with hydrating and soothing ingredients in formulations designed for sensitive or reactive skin.

Chitosan is generally well-tolerated across skin types and considered safe for cosmetic use. Those with shellfish allergies should check product sourcing, as chitosan is often derived from shellfish, though fungal-derived alternatives exist.