Propylene Glycol
Propylene Glycol (PG) is a colorless liquid with CAS# 57-55-6. Its primary role in cosmetic formulations is to improve freeze-thaw stability, ensuring products do not freeze or melt at extreme temperatures, typically used at less than 2% for this purpose. It also functions as a humectant, solvent for other ingredients, and a mild penetration enhancer at higher concentrations (10–25%). It is listed as a food-safe additive and is used in injectable drugs, indicating a well-established safety profile at low concentrations.
At low concentrations (under 5%), PG helps skin attract and retain moisture as a humectant and aids in dissolving and stabilizing other cosmetic ingredients. It may enhance the penetration of certain beneficial actives into the skin, though significant penetration enhancement requires concentrations of 10–25%, which are rarely used in cosmetics.
Can be a skin irritant when used in pure (100%) form or at concentrations above 10%; concentrations above 10% may cause irritation. Often criticized in natural cosmetics communities, though cosmetic scientists and toxicology experts consider it safe at typical use levels below 5%.
![MEDICUBE [Subscr.] Azelaic Acid 16 Calming Serum](/_next/image?url=https%3A%2F%2Fcdn.shopify.com%2Fs%2Ffiles%2F1%2F0156%2F3905%2F2336%2Ffiles%2F00_285b5a5a-20e9-44ab-a41c-05b1196738d8.jpg%3Fv%3D1749431175&w=3840&q=75)
