Science
Mechanism of Action
Polyester-8, a synthetic copolymer, forms a protective film on the skin, acting as a conditioning agent. Its primary mechanism in sunscreens involves photostabilizing UV filters like Avobenzone through a triplet quenching process, preventing degradation upon UV exposure. It also enhances product substantivity and wash-off resistance, thereby improving water resistance. Furthermore, it contributes to skin hydration and provides minor UVB absorption, though its large molecular weight prevents significant skin penetration.
Research
Clinical Evidence
High confidenceN/A
Transparency
Dusting Analysis
The Formula
Formulation
Stability
Polyester-8 significantly enhances the photostability of sunscreen actives such as Avobenzone. It is readily integrated into the oil phase of formulations due to its mutual solubility with common oil-phase ingredients, facilitating easy emulsification.
Synergies
- Avobenzone (for photostabilization)
- Diethylhexyl 2,6-Naphthalate (for synergistic photostabilization)
- Other polymeric film formers (for enhanced water resistance)
Safety
Safety Profile
Generally considered safe for use, complying with European Cosmetic Regulation (EC) 1223/2009. Clinical studies confirm it is non-irritating and non-sensitizing to the skin, and is neither genotoxic nor phototoxic. A slight potential for ocular irritation has been observed in specific tests, and while rare, contact dermatitis can occur.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Polyester-8 is a valuable synthetic polymer, particularly for enhancing sunscreen efficacy by photostabilizing UV filters and improving water resistance, while also offering mild conditioning benefits for a wide range of skin types.
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References
Sources