Stearyl Alcohol

// 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: Opacifying ingredients make formulations less clear through light scattering. These include titanium dioxide, zinc oxide, fatty alcohols, glycol stearates, and styrene/acrylates copolymer. The mechanism involves particles or crystalline structures that scatter light, reducing transmission and creating pearl-like or milky appearance. Particle size and refractive index determine degree of opacity. Used for aesthetic appeal and to mask colored ingredients.

// 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: Emollient ingredients create smooth, soft skin by filling spaces between corneocytes in stratum corneum. These include esters (isopropyl palmitate), oils (jojoba, argan), fatty alcohols, and silicones. The mechanism involves spreading on skin surface, filling microscopic irregularities, and creating lubricious film. Effects are immediate tactile improvement and visual smoothing. Emolliency measured by spreading coefficient and skin feel assessments.

// 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.

// Evidence: Emulsifying surfactants enable creation of stable oil-in-water or water-in-oil emulsions by positioning at oil-water interface, reducing interfacial tension. HLB (hydrophilic-lipophilic balance) determines emulsion type: HLB 3-6 for W/O, HLB 8-18 for O/W emulsions. Examples include polysorbate 80, ceteareth-20, glyceryl stearate. Mechanism involves forming interfacial film preventing droplet coalescence. Often used in combinations with co-emulsifiers (fatty alcohols) creating lamellar structures for enhanced stability.

// Evidence: Foam-boosting surfactants enhance lather richness, bubble size, and foam stability when combined with primary foaming agents. Typically amphoteric surfactants (cocamidopropyl betaine) or alkanolamides (cocamide DEA, cocamide MEA). Mechanism involves increasing foam viscosity through synergistic interactions with anionic surfactants, stabilizing bubble films through mixed micelle formation, and reducing drainage rate. Result is creamier, longer-lasting foam improving sensory experience.