Propylene Glycol Good Humectant Hydration Propylene Glycol at a glance Functions as a humectant (hydrating ingredient) Can enhance the delivery of key actives into skin Plays a role in keeping formulas from melting in high heat or freezing in low temps Used in thousands of personal care products with a proven track record of safety Also known as 1,2-propanediol Propylene Glycol description Propylene glycol is a humectant (hydrator) that can enhance the delivery of key active ingredients into skin. It also plays a role in keeping formulas from melting in high heat or from freezing in low temps. Also known as 1,2-propanediol, propylene glycol is used in thousands of personal care products with a proven track record of safety. As a raw material, it is a clear, purified liquid that is produced synthetically. There are some websites that state propylene glycol is really industrial antifreeze and that it is a strong skin sensitizer. They further point out that the Material Safety Data Sheet (MSDS) on propylene glycol warns users to avoid skin contact. As ominous as this sounds, it’s far from the reality of how propylene glycol is used in cosmetics formulations. The Cosmetic Ingredient Review Board and other groups have analyzed the toxicology data and exposure studies concerning topical application of propylene glycol as commonly used in cosmetics. Their conclusion was that it is safe and does not pose a health risk to consumers. Concentrations of up to 73% have been reported with leave-on products; for rinse-off products, higher concentrations are permissible. Related ingredients: Butylene Glycol Pentylene Glycol