Urea is a water-attracting molecule that skin makes as part of its natural moisturizing factor. In lotions it hydrates at lower strengths and, at higher strengths, softens and loosens thick, rough skin. People use it for very dry legs, cracked heels and rough bumps on the arms. It is well tolerated, though it can sting.
- Helps with
- very dry skin, rough bumps on arms and thighs, cracked heels, flaky patches
- Evidence
- Strong. Many clinical trials in dry, scaly skin and a long record in dermatology; higher strengths cause more mild stinging.
- Typical strength
- 4% in a moisturizing cream study; 20% in the rough-bump study
- Works well with
- glycerin, ceramides
- Be careful with
- high strengths on sensitive skin (stinging)
What does urea do for skin?
Urea is for skin that is past simply dry: shins with a fish-scale pattern, heels that crack, elbows that feel like bark, and the rough little bumps on the backs of the arms. It pulls water into the outer layer and, at higher strengths, softens the thickened, rough surface so it can shed.
Skin already contains it. A 2021 review explains: “Urea is a hygroscopic molecule (capable of absorbing water) present in the epidermis as a component of the natural moisturizing factor (NMF)”. That natural moisturizing factor is the skin’s own mix of water-holding substances inside the surface cells.
Does urea help rough bumps on the arms and legs?
In a 4-week study, 30 adults aged 18 to 65 with rough, bumpy skin on the arms or legs used a 20% urea cream once a day. Smoothness and texture improved clearly after 1 week and further by 4 weeks, most participants were satisfied with how their skin felt, and no significant side effects were reported. The study had no comparison group. For more on those bumps, see strawberry legs.
Does urea sting?
It can. In a 30-day double-blind study of 197 people with very dry skin, a cream with 4% urea and 4% salt moisturized as well as a 20% glycerin cream, but 24% of its users rated the stinging as moderate or severe, compared with 10% for glycerin. The 2021 review notes that urea’s side effects are mild and more frequent at high concentrations.
How long until you notice a difference?
In the 20% urea study, texture improved within 1 week of daily use.
How do you use urea?
Apply a urea lotion or cream once or twice a day to dry areas, ideally after a shower; see why skin feels so dry after a shower. Lower strengths suit everyday dryness; higher strengths are aimed at thick, rough areas such as heels.
Who should be careful with urea?
Stinging is the main side effect reported, and the 2021 review says side effects are more frequent at high strengths. If stinging is a problem, a glycerin-based moisturizer is a gentler swap, based on the comparison above.
- Piquero-Casals J, et al. Urea in dermatology: a review of its emollient, moisturizing, keratolytic, skin barrier enhancing and antimicrobial properties. Dermatol Ther (Heidelb). 2021;11(6):1905-1915.
- McCormick E, et al. Evaluation of a moisturizing cream with 20% urea for keratosis pilaris. J Drugs Dermatol. 2024;23(1):1274-1277.
- Lodén M, et al. A double-blind study comparing the effect of glycerin and urea on dry, eczematous skin in atopic patients. Acta Derm Venereol. 2002;82(1):45-7.
- Rawlings AV, Harding CR. Moisturization and skin barrier function. Dermatol Ther. 2004;17 Suppl 1:43-8.
Editorial content, not medical advice.