PCA

PCA molecular structure
molecular structure · PubChem
AKA: L-Pyroglutamic acid, 98-79-3, Pyroglutamic acid, Pidolic acid, 5-oxo-L-proline, (2S)-5-oxopyrrolidine-2-carboxylic acid, Pyroglu, GLUTIMIC ACID, (S)-(-)-2-Pyrrolidone-5-carboxylic acid, 5-L-Oxoproline
Synthetic
Humectant
Amino Acid
Clean
L-2-Pyrrolidone-5-carboxylic acid
Effective at 25.0%
Solubility 476000
Formula
C5H7NO3
Mol. Weight
129.11
CAS #
98-79-3
Form
Liquid
State
Solid; [Merck Index] White crystalline powder; [Alfa Aesar MSDS]
Functions
Humectant
A moisture magnet. Pulls water from the air and deeper skin layers up to the surface to keep skin plump and hydrated.
Moisturising
Locks In Moisture
Traditional Use
Pyroglutamic acid (PCA) is a naturally occurring amino acid derivative that is a primary component of skin's natural moisturizing factor (NMF). Modern skincare began incorporating it in the 1970s-1980s once its hydrating mechanism was understood.
EWG
2
CIR
Reviewed by CIR
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
all-shades-safe
Concentration Guide
5e-05%
50.0%
0%100%
Reported use
CIR reported use: 0.00005-0.05 | 0.001 (as 50% conc)
Regulatory Status
USAunder review
CANADA✔ permitted
Regulatory Agencies
Skin Types
●all-skin-types
Best For
Dehydration
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