Polyethylene Terephthalate
INCI: POLYETHYLENE TEREPHTHALATE
Reviewed by Rosie · Last updated 14 Aug 2026
A synthetic polymer that forms a protective layer on the skin surface
Best For Skin Types
All
Addresses
Usage Frequency
As tolerated
What Is Polyethylene Terephthalate?
Polyethylene terephthalate (PET) is a synthetic polymer — a long-chain plastic material — commonly used in packaging and textiles. In skincare formulations, it functions as a film-forming agent, meaning it creates a thin, continuous layer across the skin's surface when applied.
The ingredient is used sparingly in skincare products (found in approximately 0.3% of formulations) and works by adhering to the skin to form a protective barrier. This film-forming property is its primary cosmetic function.
How It Works
PET functions as a film-forming agent by depositing on the skin and setting to create a thin, continuous protective layer. This physical barrier sits atop the skin rather than penetrating it, helping to seal in moisture and defend against external irritants.
Clinical Evidence & References
Research into PET has largely focused on its potential as a biocompatible scaffold for cell delivery in wound healing applications, rather than its direct cosmetic effects on intact skin. Some studies suggest PET membranes can support cell viability and function, which may have therapeutic implications for severe skin injuries, though this lies outside typical skincare use.
Direct evidence on how PET performs as a cosmetic film-former in skincare products remains limited. The ingredient's rarity in formulations (0.3% of products) suggests it may be reserved for specific applications rather than being a widespread skincare staple.
Published Research
How to Use
PET-containing products should be applied to clean, dry skin. As with any film-forming ingredient, you may wish to cleanse thoroughly at the end of the day to remove the layer and allow the skin to breathe. If combining with other actives, apply PET-containing products last, as the film may reduce penetration of other ingredients.
Safety & Precautions
Frequently Asked Questions
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