Polyquaternium-73

Polyquaternium-73 is a synthetic polymer — a large chain-like molecule made up of repeated units. It is positively charged, which allows it to bind to hair fibres (which carry a negative charge). This ingredient is primarily used in haircare formulations rather than skincare.In haircare, polyquaternium-73 works as a film-former and conditioning agent. It adheres to the hair shaft, creating a protective layer that can reduce frizz, improve shine, and enhance combability. It also has antistatic properties, helping to manage flyaway strands.

Polyquaternium-73 is a cationic (positively charged) polymer that electrostatically adheres to hair fibres, which naturally carry a negative charge. Once bound to the hair surface, it forms a thin, continuous film.This film acts as a barrier, smoothing the outer layer (cuticle) of each hair strand. By filling microscopic irregularities and creating a more uniform surface, it reduces light scatter (which causes dullness and frizz), increases shine, and lowers the friction between adjacent hairs. The antistatic effect occurs because the deposited polymer prevents the accumulation of static el…

Polyquaternium-73 is typically found in leave-in conditioners, styling products, and rinse-off treatments at low concentrations. For best results, apply to damp or dry hair, focusing on mid-lengths and ends rather than the scalp. If using a rinse-off product, follow the instructions on the packaging; if using a leave-in product, use sparingly to avoid product buildup or heaviness.

Polyquaternium-73 is generally considered safe and well-tolerated in cosmetic products. It is approved for use in both the EU and US. Buildup may occur with heavy or frequent use of leave-in products, which can occasionally lead to dull or greasy-looking hair.