Cetyl Isononanoate

AKA: Hexadecyl isononanoate, Isononanoic acid, Hexadecyl ester
Synthetic
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.
Formula
C25H50O2
Mol. Weight
382.70
CAS #
84878-33-1
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
A synthetic ester developed in the 20th century as a lightweight conditioning and emollient ingredient. Designed to provide skin conditioning benefits without occlusive residue in modern cosmetics.
EWG
1
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
ewg-1
medical-approval
pregnancy-nursing-safe
all-shades-safe
Regulatory Status
USApermitted
EUrestricted
JAPANrestricted
CANADArestricted
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