Oleyl Phosphate

AKA: Phoslex A 18D, Nostaphat KO 300N, Oleyl alcohol phosphate, 9-Octadecen-1-ol, 37310-83-1

Synthetic

Cleanser

Emulsifier

Clean

Phosphoric acid, 9-(Z)-octadecenyl esters (mono- and di-)

Effective at 2.11%

Formula

C18H39O5P

Mol. Weight

366.50

CAS #

37310-83-1

Form

Powder

State

Other Solid; Liquid; Water or Solvent Wet Solid

Functions

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 Cleansing

Surfactant Emulsifying

Moisturizing

Antimicrobial

Fights Acne

Lifts away dirt and oil

Mixes oil and water

Traditional Use

Developed as a synthetic phosphate ester in the 20th century. Used in cosmetics as an emulsifier and conditioning agent with no traditional use history.

EWG

CIR

Safe as used

Pregnancy

Yes

CIR Safety Findings

Not a Sensitizer

medical-approval

all-shades-safe

Concentration Guide

0.02%

4.2%

0%6%

Reported use

CIR reported use: 0.02-4.2

Regulatory Status

USA✔ permitted

EU⚠ restricted

JAPAN⚠ restricted

CANADA⚠ restricted

Regulatory Agencies

EWG CIR FDA EU COSING Health Canada

Skin Types

●all-skin-types

Best For

General

Pregnancy & Breastfeeding Safe

Yes

The paper trail

🔬Peer-reviewednone on file

⚖️Regulatory1 listing →

🛡️Safety-assessed2 reviews →

Counts, not a verdict. A listing isn't a study. The trail, you decide.

Verified Jun 2026

Data: PubChem · CosIng · EWG · CIR