Isoprene/Pentadiene Copolymer
AKA “Isoprene/Pentadiene Copolymer, Synthetic Rubber
Synthetic
Ingredient Facts
Isoprene/pentadiene copolymer
AKA: Synthetic Rubber
Synthetic · Emollient · EWG: 4
Synthetic
Emollient
Occlusive
Skin Conditioner
Synthetic
Clean
Helps create a smooth, lightweight texture that glides effortlessly onto skin without feeling heavy or sticky.
CAS #
31303-93-2
Form
Liquid
State
Solid
See origin →
Functions
Viscosity Controlling
Film Forming
Creates a physical seal on skin to lock moisture in and keep irritants out. The "slugging" ingredient — barrier protection.
Emollient
Fills in the tiny cracks between skin cells to make everything feel smooth and soft. The "silky finish" ingredient.
Smoothing
Controls Viscosity
Traditional Use
A synthetic polymer developed in the 20th century for use in cosmetic formulations. Designed to improve product texture, adhesion, and wear properties in makeup and skincare products.
Skin Types
all-skin-types
Best For
General
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Yes
EWG
4
CIR
Insufficient
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Regulatory Status
USAunder review
EUrestricted
JAPANrestricted
CANADArestricted
Verified Feb 2026
Data: CosIng · EWG · CIR