Polyester-8 Good Film-Forming Agent Hydration Polyester-8 at a glance Emollient film-forming agent Improves the performance and adherence of sunscreens Considered non-irritating Made using synthetic polymer technology Polyester-8 description Polyester-8 is a synthetic copolymer (molecule composed of many repeating units) of adipic acid, octyldodecanol, and neopentyl glycol. Its primary role in skin care is film-forming and conditioning agent. A secondary but very important role of polyester-8 is in sunscreens, where it works to improve adherence to skin and resistance to coming off in water or with friction (as in rubbing of skin). This ingredient also helps stabilize avobenzone by “quenching” electrons generated when avobenzone is exposed to UV light, which would ordinarily lead to it breaking down. Some brands are using polyester-8 instead of octocrylene to stabilize avobenzone since the former is considered non-irritating while some people find octocrylene sensitizing around the eyes. Usage levels of polyester-8 in skin care is typically 1–3% when the goal is photostabilizing avobenzone; however, lower amounts may be used for its other properties. In some cases, polyester-8 may be used with octocrylene since it allows for a lower concentration of this ingredient, which is likely to improve tolerability. Related ingredients: Adipic Acid/Neopentyl Glycol/Trimellitic Anhydride Copolymer