Isoprene/Pentadiene Copolymer

AKA: Synthetic Rubber

Synthetic

Not Clean

1,3-Pentadiene, polymer with 2-methyl-1,3-butadiene

CAS #

31303-93-2

Form

Liquid

State

Solid

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.

EWG

CIR

Safe as used

Pregnancy

Yes

CIR Safety Findings

Not a Sensitizer

medical-approval

all-shades-safe

Regulatory Status

USA✔ permitted

EU⚠ restricted

JAPAN⚠ restricted

CANADA⚠ restricted

Regulatory Agencies

EWG CIR FDA EU COSING Health Canada

Skin Types

●all-skin-types

Best For

General

Pregnancy & Breastfeeding Safe

Yes

The paper trail

🔬Peer-reviewed1 paper →

⚖️Regulatory1 listing →

🛡️Safety-assessed1 review →

Counts, not a verdict. A listing isn't a study. The trail, you decide.

Verified Jun 2026

Data: CosIng · EWG · CIR