Glossary
A naturally occurring compound found in human skin as part of the natural moisturizing factor (NMF). In skincare, urea is used at various concentrations for different effects: low concentrations (2 to 10 percent) as a powerful humectant moisturizer, and higher concentrations (20 to 40 percent) as a keratolytic agent that softens and removes thickened, dead skin.
Urea's effects depend heavily on concentration. At 2 to 10 percent, urea functions as an exceptional moisturizer by attracting and binding water molecules in the skin's outer layers. It is one of the most effective humectants known, outperforming glycerin and hyaluronic acid in some clinical comparisons for sustained hydration.
At 20 to 40 percent concentration, urea becomes keratolytic: it breaks down the protein bonds (keratin) in thickened, dead skin. At these levels, it is used to treat calluses, severely cracked heels, keratosis pilaris, and other conditions involving excessive keratin buildup. Prescription-strength urea products can reach 40 to 50 percent for addressing stubborn calluses and fungal nail conditions.
Despite being a naturally occurring skin component, urea in commercial skincare products is typically synthesized rather than derived from natural sources. This does not affect its safety or efficacy, but it means urea products do not fit the purely natural ingredient profile that some consumers prefer.
For those seeking natural alternatives to urea's moisturizing action, raw honey provides humectant properties through its natural sugar composition, and beeswax provides sustained barrier protection. While these do not match urea's specific keratolytic activity at high concentrations, they provide excellent daily moisturizing support that reduces the need for concentrated treatments.
No. While urea was originally discovered in urine (hence its name), the urea used in skincare and cosmetics is synthetically produced from ammonia and carbon dioxide. It is chemically identical to natural urea but is manufactured, not derived from biological sources.
For general dry skin: 5 to 10 percent. For very dry, rough skin or mild keratosis pilaris: 10 to 20 percent. For calluses, severely cracked heels, or stubborn KP: 20 to 40 percent. Start with a lower concentration and increase if needed.
At low concentrations (under 10 percent), urea is rarely irritating. At higher concentrations (20 percent and above), it can cause stinging on broken or very sensitive skin. It should not be applied to open wounds or actively inflamed areas.
Keep Learning
Browse hundreds of terms covering honey, beekeeping, and natural skincare.