Isobutyl Polysilsesquioxane
AKA “Pentacyclo(9.5.1.13, 13)octasiloxane, Pentacyclo[9.5.1.13, RefChem:859707, PSS-OCTAISOBUTYL SUBSTITUTED 97”
Synthetic
Ingredient Facts
Isobutyl polysilsesquioxane
AKA: Pentacyclo(9.5.1.13, 13)octasiloxane, Pentacyclo[9.5.1.13, RefChem:859707, PSS-OCTAISOBUTYL SUBSTITUTED 97
Synthetic · Film Forming · EWG: 4
Synthetic
Occlusive
Skin Conditioner
Silicone
Synthetic
Clean
Strengthens and conditions nails, helping them stay flexible and resistant to breakage while creating a smooth, polished finish.
Formula
C32H72O12Si8
Mol. Weight
873.60
CAS #
221326-46-1
Form
Liquid
See origin →
Functions
Nail Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Film Forming
Creates a physical seal on skin to lock moisture in and keep irritants out. The "slugging" ingredient — barrier protection.
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Locks In Moisture
Antioxidant Protection
Strengthens nails
Traditional Use
Modern silicone-based polymer developed for cosmetics in the late 20th century. Used to provide a lightweight, silky texture and improved spreadability in skincare and color cosmetic formulations.
Skin Types
●all-skin-types
Best For
General
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Yes
Verified Feb 2026
Data: PubChem · CosIng · EWG · CIR