Urea
A skin-identical humectant from the skin's own moisturising factor; low strengths hydrate, higher strengths soften rough, thickened skin.
urea, carbamide
Dry & dehydrated skin · Barrier support · Body texture & stretch marks
What it does
Urea is a component of urine, although synthetic versions are used in cosmetics. It is an essential part of the skin's natural moisturising factor (NMF) and a common ingredient in hydrating products. At higher concentrations, urea also acts as a keratolytic, softening and loosening rough, thickened skin.
How it works
In small amounts, urea has beneficial water-binding and mild exfoliating properties for skin. As a humectant, it draws water into the outer layer of the skin and helps it stay there, while loosening the bonds between dead surface cells so they shed more easily. From around 10%, that softening effect comes to the fore, which is why stronger urea creams are used on rough heels, elbows and knees. In larger concentrations it can cause sensitivity.
MG says
For very dry or sensitised skin, keep urea to low concentrations, around 5–10% unless your doctor advises otherwise, and apply your moisturiser straight after bathing, while the skin is still damp. On the face, Auteur's Definitive Hyaluron Activator lists urea high in its formula, alongside sodium lactate and sodium PCA, two more of the skin's own moisturising factors.
Cautions
Urea is generally well tolerated at low strengths, but it can sting on broken, cracked or very sensitive skin, so patch test first. Keep stronger formulas, from around 10%, for rough areas such as heels and elbows rather than the face.
