Ingredient Encyclopedia

Welcome to the Ingredient Encyclopedia

Discover what’s inside your skincare — from retinol to aloe vera — with clear guides on benefits, uses, and safety.

Ingredient Encyclopedia

Propylene Glycol – Benefits, Side Effects & Uses

by ThankMeNow Editors on Sep 10, 2025
Propylene Glycol is a versatile, low-molecular-weight diol (humectant) that serves as one of the most reliable multi-taskers in skincare. While it is often unfairly scrutinized, its primary role is to act as a solvent and delivery vehicle, ensuring that active ingredients remain stable and are distributed evenly across the skin. Its small molecular size allows it to penetrate the surface layer more efficiently than larger humectants, carrying hydration and actives deeper into the stratum corneum. It provides a "slippery" glide that makes products feel effortless to apply, and unlike drying alcohols, it leaves behind a subtle, hydrated finish that prevents the "tight" sensation common in treatment-heavy routines.