Urea

Humectant that helps skin retain moisture and can gently exfoliate. Urea functions as a potent humectant by attracting and binding water within the stratum corneum, thereby increasing skin hydration and elasticity. At higher concentrations, it exhibits keratolytic properties by disrupting hydrogen bonds in keratin and denaturing proteins, leading to increased desquamation of corneocytes. Additionally, urea can improve skin barrier function by normalizing epidermal differentiation and lipid synthesis, and it can act as a penetration enhancer for other topical agents.

Urea is generally considered safe for use in cosmetics, affirmed by the CIR Expert Panel. It has a low potential for sensitization, though higher concentrations can cause transient stinging or irritation, particularly on compromised or sensitive skin.

Look for products with 2-40% (most moisturizing formulas use 2-10%, while keratolytic formulations for conditions like xerosis or ichthyosis use 10-40%) for clinical efficacy.