Key Functions in Skincare and Cosmetics Humectant: Draws water from the air into the skin to maintain hydration. Solvent: Dissolves hard-to-mix active ingredients, such as salicylic acid, helping formulas blend smoothly. Emollient: Softens the skin and creates a smooth, non-sticky finish. Preservative Booster: Enhances the performance of preservatives to extend product shelf life.