Urea

What it does

Part of the skin's own natural moisturising factor. It draws water into the outer layer of skin and, at higher strengths, softens and loosens thick, scaly skin.

Benefits

Moisturises at up to about 10% and becomes keratolytic above that, which is why it is a staple for very dry, rough or scaly skin. Studies suggest it also strengthens barrier function.

Concerns & Risks

Can sting on broken or inflamed skin, especially at higher strengths. No meaningful systemic risk.