Butyl Stearate
molecular structure · PubChem
AKA: 123-95-5, Butyl octadecanoate, N-Butyl stearate, Octadecanoic acid, Butyl ester, Kesscoflex BS, Kessco BSC, N-Butyl octadecanoate, Butyl octadecylate, Starfol BS-100
Plant-Derived
Emollient
Skin Conditioner
Clean
The CIR Expert Panel concluded that the alkyl esters, listed subsequently, are safe in the present practices of use and concentration described in this safety assessment when formulated to be non-irritating.
Effective at 21.5%
Solubility Insoluble in water; soluble in ethanol; very soluble in acetone
Formula
C22H44O2
Mol. Weight
340.60
CAS #
123-95-5
Form
Liquid
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.
Emollient
Fills in the tiny cracks between skin cells to make everything feel smooth and soft. The "silky finish" ingredient.
Locks In Moisture
Traditional Use
Synthetic ester developed as a cosmetic emollient and conditioning agent. Created to provide texture improvement and skin compatibility in skincare and color cosmetic formulations.
EWG
1
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
ewg-1
medical-approval
pregnancy-nursing-safe
all-shades-safe
Concentration Guide
0.0008%
43.0%
0%60%
Reported use
CIR reported use: 0.0008-12 | 0.002-43
Regulatory Agencies
Skin Types
●all-skin-types, gentle
Best For
Dryness
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️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