Urea

Urea is a unique double-acting ingredient: at 3–10% it works as a powerful humectant and NMF component that binds water and softens skin; at 20–40% (pharmacy-grade) it becomes a keratolytic that dissolves the protein bonds of thick, calloused, or severely flaky skin. It is medically proven for ichthyosis, psoriasis support, cracked heels, and keratosis pilaris. Cosmetic creams at 5–10% relieve rough upper arms, dry shins, and itchy winter skin. Urea also enhances penetration of accompanying actives. Downside: slight sting on cracked skin at higher strengths. Dermatology’s most underrated all-rounder for genuinely dry, rough skin problems.