Can you use lactic acid with urea?
The chemistry
Urea is a natural moisturizing factor: at low concentrations (around 5 to 10 percent) it draws water into the outer layer, and at higher concentrations (20 percent and above) it softens and breaks down thick, scaly skin (Celleno 2018). Lactic acid is an alpha hydroxy acid that also belongs to the skin's own moisturizing factors; it loosens dead cells and, in a study using 5 and 12 percent lotions, increased the firmness and thickness of the skin (Smith 1996). Together they hydrate and smooth at the same time, which is why they are used for heels, elbows, keratosis pilaris and xerosis. In a randomized trial of a moisturizer for dry feet, the urea and lactic acid formulation outperformed its vehicle (Pham 2002).
Best for
Cracked heels, keratosis pilaris, rough elbows, dry shins.
Strength
Low urea hydrates; high urea softens thick skin.
Face?
Use low strengths only, and patch test.
Common mistakes
These creams sting on cracked or broken skin, so treat open fissures with a plain ointment first. For keratosis pilaris, the bumpy 'chicken skin' on the upper arms, apply the cream daily for several weeks; the bumps flatten but return if you stop. For heels, apply at night and wear cotton socks to boost absorption. A 10 percent urea lotion is generally fine for the face if you are very dry, but high-strength foot creams are too much for facial skin.
Your routine
Morning
- Gentle body wash
- Urea and lactic acid lotion on dry areas
- Sunscreen on exposed skin
Evening
- Shower
- Urea and lactic acid cream on heels or arms
- Cotton socks for feet
Go slower if
Lactic acid increases sun sensitivity (Kaidbey 2003). Avoid on eczema flares with cracked skin; it may sting badly. People with diabetes and foot problems should follow their foot care team's advice.
Evidence strength
Good for urea in dry skin conditions; moderate for lactic acid. The combination has trial support for dry feet.
Products with lactic acid
The Ordinary Lactic Acid 10% + HA
Picked for lactic acid
10% lactic acid paired with glycerin and hyaluronic acid crosspolymer.
Buy on Amazon (opens in a new tab)FAQ
Will this help my child's rough arms?
Keratosis pilaris is common in children. Ask a doctor about strength first, because these creams can sting young skin.
Why does my heel cream tingle?
Both ingredients sting on micro-cracks; it usually fades within days as the skin heals.
Can I use a urea and lactic acid cream on psoriasis plaques?
Urea creams are often used to soften psoriasis scale so prescription treatments penetrate better, but plaques can sting with acids. Ask your dermatologist which strength fits your plan (Celleno 2018).
Related combinations
- RetinolYes, with timing
- Vitamin CYes, with timing
- NiacinamideYes
- TretinoinYes, with timing
- Salicylic AcidYes, with care
- Hyaluronic AcidYes
- Glycolic AcidYes, with care
- Benzoyl PeroxideYes, with timing
Sources
- Celleno L. Topical urea in skincare: a review. Dermatol Ther. 2018;31(6):e12690.
- Smith WP. Epidermal and dermal effects of topical lactic acid. J Am Acad Dermatol. 1996;35(3 Pt 1):388-391.
- Pham HT, Exelbert L, Segal-Owens AC, Veves A. A prospective, randomized, controlled double-blind study of a moisturizer for xerosis of the feet in patients with diabetes. Ostomy Wound Manage. 2002;48(5):30-36.
- Kaidbey K, et al. Topical glycolic acid enhances photodamage by ultraviolet light. Photodermatol Photoimmunol Photomed. 2003;19(1):21-27.