Isostearic Acid
AKA: Isooctadecanoic acid, 16-METHYLHEPTADECANOIC ACID, 2724-58-5, 30399-84-9, Heptadecanoic acid, 16-methylmargaric acid
Synthetic
Skin Conditioner
Synthetic
Clean
16-methylheptadecanoic acid is a methyl-branched fatty acid that is heptadecanoic acid (margaric acid) substituted by a methyl group at position 16. It is a long-chain fatty acid, a branched-chain saturated fatty acid and a methyl-branched fatty acid. It is functionally related to a heptadecanoic acid.
Formula
C18H36O2
Mol. Weight
284.50
CAS #
30399-84-9, 2724-58-5
Form
Liquid
State
Liquid; Liquid, Other Solid
Functions
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Buffering
Holds Formula Together
Removes Impurities
Emulsifier
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
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory0 listings
🛡️Safety-assessed3 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR