murphyStearic Acid
AKA: Octadecanoic acid, 57-11-4, N-Octadecanoic acid, Stearophanic acid, Stearex Beads, Cetylacetic acid, 1-Heptadecanecarboxylic acid, Pearl stearic, Industrene R
Plant-Derived
Cleanser
Emulsifier
Acid
Clean
OriginDerived from vegetable oils such as palm, coconut, and animal fats through saponification or hydrolysis processes. Isolated and purified through fractional distillation or crystallization to obtain the individual fatty acid compound.
Octadecanoic acid is a C18 straight-chain saturated fatty acid component of many animal and vegetable lipids. As well as in the diet, it is used in hardening soaps, softening plastics and in making cosmetics, candles and plastics. It has a role as a plant metabolite, a human metabolite, a Daphnia magna metabolite and an algal metabolite. It is a long-chain fatty acid, a saturated fatty acid and a straight-chain saturated fatty acid. It is a conjugate acid of an octadecanoate. It derives from a hydride of an octadecane.
Solubility 1 to 10 mg/mL at 73 °F (NTP, 1992)
Formula
C18H36O2
Mol. Weight
284.50
CAS #
57-11-4
Form
Liquid
Skin Types
●all-skin-types, gentle
Functions
Cleansing
Makes oil and water mix so dirt, makeup, and sunscreen can actually be washed away. The reason your face wash foams.
Emulsion Stabilising
Forces oil and water to stay mixed instead of separating into layers. The unsung hero holding your lotion together.
Refatting
Cleansing
Makes oil and water mix so dirt, makeup, and sunscreen can actually be washed away. The reason your face wash foams.
Emulsifying
Forces oil and water to stay mixed instead of separating into layers. The unsung hero holding your lotion together.
Surfactant Emulsifying
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.
EWG
1
CIR
Safe as used
Pregnancy
—
CIR Safety Findings
Not Phototoxic
Product formulation test found no phototoxicity in the CIR safety assessment (CIR 161)
Mixed Eye Irritation Results
7 studies / 1 irritating / 5 mixed / 1 not irritating / reactions minimal to mild (CIR 161 and 777)
Mixed Skin Irritation Results
37 studies / 20 irritating / 5 mixed / 12 not irritating / reactions minimal to moderate (CIR 161 and 777)
Mixed Sensitization Results
12 studies / 1 sensitizing / 1 mixed / 10 not sensitizing (CIR 161 and 777)
Concentration Guide
Leave-on0.0001–21%
Rinse-off0.00006–37.4%
0%50%100%
CIR reported use · 2016 survey
Regulatory Agencies
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR