Centella AsiaticavsGlycerin

The four key triterpenoid saponins—madecassoside, asiaticoside, madecassic acid, and asiatic acid—exert distinct but complementary mechanisms. Madecassoside and asiaticoside are anti-inflammatory: they inhibit NF-κB nuclear translocation and IκB kinase activity, reducing TNF-α, IL-6, and IL-1β production in keratinocytes and dermal cells. Madecassic acid and asiatic acid (the aglycone forms) stimulate type I and III collagen synthesis in fibroblasts by upregulating collagen gene expression and procollagen production. All four compounds promote wound healing by stimulating angiogenesis via VEGF (vascular endothelial growth factor) upregulation, fibroblast proliferation and migration, and extracellular matrix remodeling. Centella extracts also increase superoxide dismutase (SOD) and catalase activity in skin cells, enhancing endogenous antioxidant defense. The triterpenes may modulate TGF-β and Smad signaling. TECA (Titrated Extract of Centella Asiatica) standardizes these actives for consistent clinical efficacy.

Glycerin (glycerol) is a small three-carbon polyol (92 Da) that penetrates the stratum corneum via intercellular lipid and transcellular routes. It acts as a humectant through osmotic mechanisms—creating a concentration gradient that draws water from the atmosphere (when humidity >65%) and from deeper epidermal layers. Glycerin upregulates aquaporin-3 (AQP3), a glycerol-permeable water channel in keratinocyte membranes that facilitates water and glycerol transport. It supports the natural moisturizing factor (NMF)—amino acids, lactate, and urea that maintain stratum corneum water-holding capacity. Glycerin modulates keratinocyte differentiation and may enhance lipid lamellae organization. Mild antimicrobial activity occurs through osmotic stress. Clinical studies demonstrate hydration efficacy comparable to or exceeding hyaluronic acid.