Polyester-4 ●
TL;DR. This ingredient is primarily a synthetic film-former. It helps create a flexible, water-resistant layer that improves wear, adhesion, and even distribution in sunscreens, color cosmetics, and styling products.
What does Polyester-4 do in a cosmetic formula?
This ingredient is primarily a synthetic film-former. It helps create a flexible, water-resistant layer that improves wear, adhesion, and even distribution in sunscreens, color cosmetics, and styling products.
Is Polyester-4 clean?
From a clean-beauty perspective, this ingredient has friction because it is a synthetic polymer with limited skin penetration but a persistence profile that many stricter standards scrutinize. It is not a common irritation or allergen concern, but its polymer status places it outside many natural-leaning frameworks.
Is Polyester-4 sustainable?
This material is typically made from petrochemical-derived monomers and is not considered readily biodegradable. Its main sustainability issue is environmental persistence rather than acute skin-safety concern.
Is Polyester-4 COSMOS-approved?
It is not permitted under COSMOS-natural or COSMOS-organic standards as a conventional synthetic film-forming polymer. It has weak Green Chemistry alignment because it relies on non-renewable feedstocks and does not readily break down after use.
How does Polyester-4 work chemically?
The molecule is a high molecular weight synthetic polyester designed to form a continuous film after solvent or water evaporation. It is generally used at low single-digit percentages, with performance depending on solvent system, neutralization or dispersion format, and compatibility with UV filters, pigments, waxes, and other film-formers.
Last updated 2026-05-13