Butylene Glycol

// 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: Humectant ingredients draw water from the environment and deeper skin layers through hygroscopic properties. Common humectants include glycerin, propylene glycol, hyaluronic acid, urea, and alpha-hydroxy acids. These contain multiple hydroxyl groups or other hydrophilic functional groups that form hydrogen bonds with water molecules. Mechanism involves attracting water to the stratum corneum, reducing transepidermal water loss, and increasing skin hydration.

// Evidence: Skin conditioning ingredients enhance appearance, texture, and health of skin through various mechanisms. This broad category encompasses emollients, humectants, occlusives, and other agents that improve skin feel, appearance, and function. May work by moisturizing, smoothing, softening, or protecting skin. Effects include improved tactile properties, enhanced barrier function, and better overall skin condition.

// Evidence: Solvents dissolve, dilute, or disperse other ingredients creating homogeneous solutions. Water is universal solvent for hydrophilic ingredients. Organic solvents include ethanol (dissolves fragrances, some actives), propylene glycol, and glycerin. Selection based on polarity matching between solvent and solute. Mechanism involves disrupting intermolecular forces in solute and surrounding with solvent molecules. Critical for maintaining ingredient solubility and product stability.