Polybutylene Terephthalate

What is Polybutylene Terephthalate?

Polybutylene terephthalate is a tough, semi-crystalline thermoplastic polyester made from terephthalic acid and 1,4-butanediol through polycondensation. In cosmetics, it serves in makeup, hair styling aids, and sun protection items. It functions by creating a sheer, flexible sheath over skin or hair that boosts staying power against moisture, friction, and movement. This polymeric layer helps makeup adhere evenly and last longer while shielding hair from humidity and touch-ups. Additionally, it modulates formula thickness, ensuring spreadability, suspension of other components, and a pleasant sensory feel without stickiness. Its chemical stability and smooth texture contribute to refined product finishes across diverse applications.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1 View on EWG →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Film former
Creates a continuous film on skin or hair to improve wear, water resistance, transfer resistance, shine, or hold in sunscreens, makeup, and styling products.
Hair fixative
Provides style hold by forming a film on hair, helping maintain shape, reduce frizz, and improve durability in sprays, gels, and mousses.
Viscosity controlling agent
Adjusts thickness to the desired level for stability and usability, improving dispensing, suspension, and texture across many formulation types.

Benefits

Forms a protective layer that improves makeup durability and water repellency.

Offers reliable hold for hairstyles, reducing flyaways and extending style longevity.

Optimizes product consistency for effortless blending and even coverage.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Individuals seeking long-lasting, smudge-proof cosmetics.
Those sensitive to synthetic polymers.
People with active lifestyles needing humidity-resistant hair products.
People preferring fully natural or plant-based formulations.
Users wanting stable, easy-to-apply sunscreens and lotions.
Individuals with rare polyester allergies.

Safety Notes

  • Low hazard rating with minimal skin penetration due to large molecular size.
  • Non-comedogenic, unlikely to contribute to pore blockage.

Frequently Asked Questions about Polybutylene Terephthalate

What is polybutylene terephthalate used for in cosmetics?

It acts as a film former for skin protection, hair fixative for style hold, and viscosity controller for better texture.

Is polybutylene terephthalate safe for daily use?

It carries a low safety hazard rating and shows no significant risks in typical cosmetic applications.

Does it work well in makeup products?

Yes, it enhances wear, water resistance, and smoothness in foundations, lip colors, and sunscreens.