Stearic Acid

// Evidence: Cleansing ingredients remove sebum, dirt, cells, and cosmetics through surfactant action, emulsification, or solubilization. Surfactants reduce surface and interfacial tension, allowing water to wet oily surfaces. Micelle formation enables hydrophobic substances to be solubilized and rinsed away. Must balance efficacy with mildness to avoid stripping natural lipid barrier.

// Evidence: Emulsion stabilizers maintain dispersion of immiscible phases by preventing droplet coalescence through interfacial film formation, electrostatic repulsion, steric stabilization, viscosity enhancement, or network formation. Stabilizers include polymers (carbomers, xanthan gum), proteins, and modified celluloses. The combination of primary emulsifiers with secondary stabilizers creates robust lamellar liquid crystalline structures.

// Evidence: Fragrance ingredients provide aromatic appeal through essential oils, aroma chemicals, and natural extracts. These volatile compounds interact with olfactory receptors creating scent perception. Fragrance design considers top notes (high volatility), middle notes (moderate volatility), and base notes (low volatility) for scent development over time. Must consider stability, allergen content, and regulatory compliance.

// Evidence: Refatting ingredients restore the lipid barrier depleted by surfactants through oils, lipids, and emollients that deposit during rinsing. These include plant oils, fatty alcohols, lanolin, and ceramides. The mechanism involves replenishing intercellular lipids and surface sebum, preventing the tight, dry feeling from harsh cleansing. Particularly important in syndets and gentle cleansers to maintain barrier integrity while cleansing.

// Evidence: Cleansing surfactants specifically formulated for removing sebum, dirt, and impurities. Primarily anionic (sodium laureth sulfate, sodium cocoyl isethionate) and amphoteric surfactants (betaines). Mechanism involves reducing surface tension enabling water to wet oily surfaces, solubilizing lipophilic materials in micelles, and emulsifying oils for rinse-off. Cleansing efficacy balanced with mildness by surfactant selection, concentration, and pH optimization. Must avoid excessive lipid removal that compromises barrier function.