Glycerin

Glycerin — chemically known as glycerol — is a simple polyol compound that occurs naturally in all living cells as a byproduct of lipid metabolism. In the skin, it is a natural component of the natural moisturising factor (NMF) — the complex mixture of water-soluble compounds found in the corneocytes of the stratum corneum that is responsible for maintaining optimal hydration levels in the outermost skin layer. Studies have shown that glycerin levels in the skin decline with age and are significantly reduced in conditions such as xerosis, eczema, and psoriasis — suggesting that its replenishment through topical application has both cosmetic and therapeutic relevance. The hydrating mechanism of glycerin is well understood and operates on multiple levels. As a humectant, it draws water from the deeper layers of the dermis towards the surface, while simultaneously attracting atmospheric moisture into the stratum corneum — creating a reservoir of hydration that persists long after application. Critically, glycerin also interacts directly with aquaporin-3, a membrane channel protein that regulates water transport across cell membranes. By facilitating glycerol transport through this channel, topical glycerin actively supports the skin’s intrinsic hydration machinery rather than simply sitting on the surface. Beyond its hydrating properties, glycerin has been shown to accelerate the recovery of the skin’s barrier function following disruption — whether caused by detergents, UV exposure, or aesthetic treatments. It does so by supporting the synthesis and organisation of lamellar bodies, the lipid-containing structures secreted by keratinocytes that form the characteristic brick-and-mortar architecture of the stratum corneum. This combination of immediate hydration, sustained moisture retention, and active barrier repair makes glycerin one of the most versatile and evidence-based ingredients across the Forget About Age product range.