Acetyl Arginine

Acetyl Arginine 1
Acetyl Arginine 2
Acetyl Arginine 3
AKA: 210545-23-6, Ac-Arg-OH dihydrate, (S)-2-Acetamido-5-guanidinopentanoic acid dihydrate, AC-ARG-OH 2H2O, L-Arginine, Hydrate (1:2), N-ACETYL-L-ARGININE DIHYDRATE, N-Acetyl-L-arginine (dihydrate), Ac-Arg-OH.2H2O, (2S)-2-acetamido-5-(diaminomethylideneamino)pentanoic acid;dihydrate
Synthetic
Humectant
Emollient
Skin Conditioner
Amino Acid
Not Clean
L- Arginine, N(2)-acetyl-
Formula
C8H20N4O5
Mol. Weight
252.27
CAS #
210545-23-6
Form
Liquid
Functions
Humectant
A moisture magnet. Pulls water from the air and deeper skin layers up to the surface to keep skin plump and hydrated.
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 modified amino acid developed in the late 20th century for use in anti-aging skincare to support collagen production and skin barrier function.
EWG
4
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Regulatory Status
USA✔ permitted
EU⚠ restricted
JAPAN⚠ restricted
CANADA⚠ restricted
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed1 review →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR