Isostearic Acid
AKA “Isooctadecanoic acid, 16-METHYLHEPTADECANOIC ACID, Heptadecanoic acid, UNII-LZM5XA0ILL, EINECS 220-336-3, 16-methylmargaric acid”
Synthetic
Ingredient Facts
Isostearic acid
AKA: Isooctadecanoic acid, 16-METHYLHEPTADECANOIC ACID, Heptadecanoic acid, UNII-LZM5XA0ILL, EINECS 220-336-3, 16-methylmargaric acid
Synthetic · Binder · EWG: 5
Synthetic
Emulsifier
Synthetic
Clean
A gentle binding agent that helps cleanse and blend formulas together, keeping products smooth and effective on skin.
Formula
C18H36O2
Mol. Weight
284.50
CAS #
30399-84-9, 2724-58-5
Form
Liquid
State
Liquid; Liquid, Other Solid
See origin →
Functions
Binder
Cleanser
Emulsifier
Forces oil and water to stay mixed instead of separating into layers. The unsung hero holding your lotion together.
Holds Formula Together
Removes Impurities
Cleansing Surfactant
Traditional Use
A synthetic branched fatty acid derived from petrochemical processes in the mid-20th century. Designed to mimic natural fatty acids while providing improved stability and emollient properties in skincare formulations.
Skin Types
●all-skin-types
Best For
Dryness
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Yes
Final Report on the Safety Assessment of Isostearic Acid
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Isostearic Acid
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Microemulsions based on TPGS and isostearic acid for imiquimod formulation and skin delivery.
Pescina S, Garrastazu G, Del Favero E, Rondelli V, Cantù L et al.
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 2018
Verified Feb 2026
Data: PubChem · CosIng · EWG · CIR