Propylene Glycol

Propylene Glycol is a synthetic diol that has been a cosmetic industry workhorse since the 1950s, valued for its exceptional ability to attract and retain moisture while also serving as an effective solvent for active ingredients and preservatives. Its low molecular weight allows it to penetrate the stratum corneum efficiently, enhancing the delivery of other ingredients, though this same property has led to restrictions in some markets due to potential skin sensitivity at high concentrations. Formulators choose it for its multifunctionality, cost-effectiveness, and ability to reduce water activity in formulations, thereby boosting preservation, though it's increasingly being replaced by propanediol (from corn) in natural formulations.