Amino Acid

Acetyl Hydroxyproline

CAS 33996-33-7 EC 251-780-6
L-Proline, 1 Acetyl-4-Hydroxy-
Limited Data
Insufficient safety data available. Consider enriching this ingredient.
Details

Description

L-Proline, 1 Acetyl-4-Hydroxy-

Purpose

Function

HAIR CONDITIONING, HUMECTANT, SKIN CONDITIONING, SKIN CONDITIONING - EMOLLIENT, SKIN PROTECTING
Profile

Properties

Silicone
Silicone free
Compliance

Regulatory Status

EU
Permitted
Safety
EXCELLENT
US
Permitted
Absorptionlow
Sensitizationnone
MoSadequate
NOAEL200 mg/kg
ConcernNone
Verdict

Key structural amino acid in collagen with skin-conditioning, hair-conditioning, and antistatic functions; supports skin firmness and hydration; excellent safety profile as an endogenous molecule

US Note

No FDA restrictions for cosmetic use; standard amino acid with well-established safety profile

Assessment

Ratings

Comedogenic0/5
LowHigh
Irritancy0/5
LowHigh
Reference

Identifiers

CAS Number
33996-33-7
EC Number
251-780-6
Category
Amino Acid
Updated
Apr 23, 2026