Urea
Definition
Urea is a naturally occurring compound found in the skin as part of the natural moisturizing factor (NMF) — the collection of water-soluble substances in the stratum corneum that help maintain hydration. In skincare, synthetic urea is used at various concentrations for different effects. At low concentrations (2-10%), urea acts as a powerful humectant, attracting and binding water to hydrate dry, rough, or flaky skin. At moderate concentrations (10-20%), it provides both moisturizing and mild keratolytic (exfoliating) effects, helping to soften and smooth rough patches, calluses, and conditions like keratosis pilaris. At higher concentrations (20-40%), urea becomes a more potent exfoliant used to treat conditions like psoriasis, severely dry skin, and thickened nails. Urea is exceptionally well-tolerated, non-irritating for most people, and can even help other active ingredients penetrate the skin more effectively.
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