Polyquaterium-51 ●
TL;DR. This ingredient is primarily a skin and hair conditioning film-former that helps bind water, improve slip, and leave a smoother after-feel. It is often used for barrier-feel support in moisturizers, serums, cleansers, and hair-care formulas.
What does Polyquaterium-51 do in a cosmetic formula?
This ingredient is primarily a skin and hair conditioning film-former that helps bind water, improve slip, and leave a smoother after-feel. It is often used for barrier-feel support in moisturizers, serums, cleansers, and hair-care formulas.
Is Polyquaterium-51 clean?
From a clean-beauty perspective, it is generally low-irritation and not a common allergen, but it has friction because it is a synthetic quaternized polymer. Some standards scrutinize this class because of persistence and limited biodegradability rather than direct skin tolerance concerns.
Is Polyquaterium-51 sustainable?
This material is synthetic and typically derived from petrochemical methacrylate chemistry. As a high-molecular-weight water-soluble polymer, it is not expected to be readily biodegradable, which creates wastewater persistence concerns.
Is Polyquaterium-51 COSMOS-approved?
This ingredient is not permitted in COSMOS-organic or COSMOS-natural formulas because it is a synthetic quaternized polymer. Its Green Chemistry fit is limited by petrochemical feedstocks and poor biodegradability, despite low use levels and water-based delivery.
How does Polyquaterium-51 work chemically?
The molecule is a high-molecular-weight methacrylate copolymer with zwitterionic phospholipid-like side groups and hydrophobic segments, so it deposits as an ultrathin water-binding film. It is usually supplied as an aqueous solution and used at low active levels, with broad compatibility across normal skin-care pH when paired with nonreactive emulsifiers and thickeners.
Last updated 2026-05-13