INGREDIENT · HUMECTANT
Sodium PCA in skincare: a humectant with thin direct proof
Sodium PCA is a humectant used in moisturisers. It has a clean safety review and little trial evidence of its own.
You may see it written as
- Sodium PCA
- PCA
What sodium PCA is
A 2019 safety review describes PCA (2-pyrrolidone-5-carboxylic acid) and its salts, sodium PCA among them, as skin-conditioning agents that work as humectants.1 A humectant attracts and holds water.
What the safety review found
The Cosmetic Ingredient Review expert panel reassessed PCA and sodium PCA in 2019 and added calcium, magnesium and potassium salts. It concluded the ingredients are safe in cosmetics in the present practices of use and concentration. It added that they should not be used in cosmetic products in which N-nitroso compounds can form.1 The panel was set up in 1976 by the cosmetics industry’s trade association, with support from the US Food and Drug Administration and the Consumer Federation of America.2
What the trials show
Most trials test mixtures of natural moisturizing factor (NMF) molecules, not sodium PCA alone. In two double-blind studies of 35 and 33 people, lotions and creams enriched with ceramides and NMF raised skin hydration on the lower legs more than a ceramide cream over 10 days, with a statistically significant overall difference on day 10.3 The abstract does not list which molecules the formulations contained.
A 2021 study of 12 volunteers over 14 days used a formulation with NMF components and a placebo. Both disturbed the balance of water, NMF and lipids in the outer skin, and the NMF supplement reduced those effects. Over time it increased the amount of strongly bound water at 30 to 40% of the layer's depth.4 Two of its five authors work for a chemicals and ingredients company.4
A 2025 report on a moisturiser combining NMF and lipids found increases in filaggrin, hyaluronic acid and lipid levels against untreated controls in the lab, and improved barrier strength and tolerability in people with atopic dermatitis, rosacea or cosmetic intolerance syndrome.5 It tested one finished product.
How to read this
Sodium PCA has a clear safety conclusion and a believable job as a humectant. The hydration benefits shown in trials belong to whole formulas, so they cannot be credited to sodium PCA on its own.
Using sodium PCA with other products
Two of the studies above tested products that combined NMF with ceramides or lipids.3,5 Each was one product, not layered products. We did not find a source on layering sodium PCA with other products.
Sodium PCA in pregnancy and breastfeeding
We found no pregnancy- or lactation-specific evidence for this ingredient.
Evidence on cosmetic products in pregnancy is limited overall, so ask your doctor or midwife about the specific product you use.6
What you will see on the label
On a label, look for Sodium PCA and PCA. Snifff shows it as Risk-free. For the rest of the formula, see what the score means and how to read the list.
As Snifff shows itSodium PCA
Pregnancy and nursing
We found no pregnancy- or lactation-specific evidence for this ingredient.
Wording as it appears in the extension, which can change between releases.
A FEW MORE ANSWERS
Common questions about sodium pca
What is sodium PCA?
The sodium salt of PCA (2-pyrrolidone-5-carboxylic acid), used in cosmetics as a humectant that attracts and holds water.1
Is sodium PCA safe?
A 2019 review concluded PCA and its salts are safe in cosmetics as used, and said they should not be used in products where N-nitroso compounds can form.1
Does sodium PCA moisturise skin?
Moisturisers based on natural moisturizing factor mixtures raised hydration in small trials, but none of the recent abstracts we found isolates sodium PCA.3,4,5
Is Sodium PCA safe in pregnancy?
Snifff found no pregnancy-specific evidence for Sodium PCA. Ask your doctor or midwife about the product you use.
WHERE THIS COMES FROM
Sources
- Safety Assessment of PCA (2-Pyrrolidone-5-Carboxylic Acid) and Its Salts as Used in CosmeticsFiume MM, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD, et al. · International Journal of Toxicology · 2019
- Fifty years of the Cosmetic Ingredient Review (CIR) and the Expert Panel for Cosmetic Ingredient Safety: an independent, transparent, and science-forward program for ingredient safety assessmentInternational Journal of Toxicology · 2026
- Natural moisturizing factor-enriched formulations compared to a ceramide-based creamBaldwin HE, Arrowitz C, Del Rosso J · Journal of Drugs in Dermatology · 2024
- Retaining skin barrier function properties of the stratum corneum with components of the natural moisturizing factor: a randomized, placebo-controlled double-blind in vivo studySchleusener J, Salazar A, von Hagen J, Lademann J, Darvin ME · Molecules · 2021
- Skin barrier benefits of a natural moisturizing factor and lipids-based moisturizer for clinically sensitive skinBernhardt KT, Zaleski E, Li WH, Patel R, Parsa R, Miller D, Draelos ZD, et al. · Journal of Drugs in Dermatology · 2025
- Cosmetic dermatology in pregnancy and lactation: a risk-benefit framework for clinical practiceKovacs T, et al. · International Journal of Dermatology · 2026
This page explains an ingredient. It is not medical advice, and it is not an assessment of any product. If you are pregnant, breastfeeding, or have a skin condition, ask your doctor or pharmacist.