Urea
Urea (also called Carbamide) is a naturally occurring compound found in the skin and classified as a natural moisturizing factor (NMF), making up approximately 7% of NMFs. It functions both as a moisturizer/humectant and as a mild keratolytic agent, capable of breaking down bonds in the protein filaggrin to free up amino acids in the skin. It is considered a skin-identical ingredient and is used in concentrations ranging from low percentages in everyday moisturizers up to 10–40% in therapeutic treatments.
Urea is a strong humectant that helps skin retain water, keeping it plump, elastic, and hydrated. As a mild keratolytic, it enhances skin barrier function and antimicrobial peptide expression. High-percentage formulations (10–40%) have demonstrated effectiveness in skin disorders associated with excessive dryness and impaired barrier function, such as ichthyosis, xerosis, psoriasis, eczema, and seborrheic dermatitis.
High-percentage urea formulations (10–40%) are typically reserved for therapeutic use in specific skin disorders; use at these concentrations should be approached with care on sensitive or compromised skin.
