Polyquaternium-10

Polyquaternium-10 is a cationic cellulose-derived conditioning polymer used mainly in hair and some skin products (typically ~0.1–1%) to reduce static and improve slip/film-forming. Clinical experience and patch-test data generally show low irritation potential for this high–molecular weight polymer, but cationic polymers can occasionally provoke stinging or mild irritant reactions on compromised barriers (e.g., eczema, post-procedure) when left on the skin. Given its overall good tolerability yet non-zero risk in highly reactive patients, it fits best as very gentle rather than inert. Safety Notes: In commercial haircare and skincare, Polyquaternium-10 is most often used at very low levels (~0.01–0.10%) in shampoos/cleansers and light lotions to provide wet-comb improvement, anti-static effects, and a soft after-feel without buildup. Higher levels are seen in consumer-available high-deposition conditioners, masks, leave-in detanglers, and styling creams where slip and substantivity are prioritized; these can reach ~0.5% and, more rarely, about 1.0% in thickened, strongly conditioning leave-on formats. There is no specific EU/FDA maximum for this polymer in cosmetics, so practical upper use is mainly limited by viscosity, clarity/compatibility with anionics, potential tack/buildup, and sensory performance (rinse-off typically lower than leave-on).