Isoprene/Pentadiene Copolymer
AKA “Isoprene/Pentadiene Copolymer, Synthetic Rubber
Ingredient
Ingredient Facts
Isoprene/pentadiene copolymer
AKA: Synthetic Rubber
Ingredient · Viscosity Controlling · EWG: 4
Synthetic
Not Clean
1,3-Pentadiene, polymer with 2-methyl-1,3-butadiene
CAS #
31303-93-2
Form
Liquid
State
Solid
See origin →
Functions
Viscosity Controlling
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
Pregnancy & Breastfeeding Safe
Yes
EWG
4
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Regulatory Status
USApermitted
EUrestricted
JAPANrestricted
CANADArestricted
Verified Jun 2026
Data: CosIng · EWG · CIR