murphyIsobutyl Stearate
AKA: 2-Methylpropyl octadecanoate, Octadecanoic acid, 2-methylpropyl ester, Stearic acid, Isobutyl ester, Isobutyl octadecanoate, HSDB 2177, Stearic acid isobutyl ester, Uniflex IBYS
Plant-Derived
Emollient
Skin Conditioner
Clean
OriginDerived from stearic acid and isobutanol, both petroleum-derived or synthesized from natural oils through chemical processes. Produced through esterification, where stearic acid and isobutanol react together under catalytic conditions to form the ester compound.
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.
Solubility Very sol in ether
Formula
C22H44O2
Mol. Weight
340.60
CAS #
646-13-9
Form
Liquid
Skin Types
●all-skin-types
Best For
Dryness
Pregnancy & Breastfeeding Safe
Yes
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
The paper trail
🔬Peer-reviewednone on file
⚖️Regulatory1 listing →
🛡️Safety-assessed3 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
EWG
1
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
2 studies / 2 not sensitizing (CIR 189 and 623)
Not Phototoxic
Human test found no phototoxicity in the CIR safety assessment (CIR 623)
Skin Irritant in Testing
3 studies / 3 irritating / reactions mild (CIR 189 and 623)
Concentration Guide
CIR's newest survey reports no concentration of use.
CIR · 2012 survey
Regulatory Agencies
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR