Transepidermal water loss (TEWL) occurs when intercellular lipids—specifically cholesterol, ceramides, and fatty acids—are depleted by harsh surfactants or dry ambient air. Phytosterols, plant-derived structural analogues of cholesterol, directly integrate into human stratum corneum matrices.
The Golden Ratio: 3:1:1 Molecular Balance
Clinical studies show that barrier restoration is significantly accelerated when botanical oils deliver ceramides, fatty acids, and phytosterols in a balanced 3:1:1 molar ratio. Seed oils like Baobab, Evening Primrose, and Meadowfoam supply these critical building blocks.
Customizing Lipid Ratios
Depending on your ambient climate and dryness level, your required phytosterol density varies. Use our interactive Skin Routine Builder to calculate your ideal seasonal lipid layer.