Urea

Urea is naturally found in the skin’s natural moisturizing barrier, which is also made up of amino acids and more. Your body’s availability of urea decreases with age. If you’re using retinoids or exfoliating acids on your skin and see irritation or dryness, stick to lower concentrations of urea. Due to its exfoliating properties, it might irritate your skin.

Type of Ingredient: Keratolytic emollient (tissue softener)
Main Benefits: Dissolves the intracellular matrix, which loosens dead, scaly skin. This makes it ideal for treating calluses, dermatitis, psoriasis, eczema, and keratosis pilaris. It also draws moisture into the skin for serious hydration.
Who Should Use It: Anyone with dehydrated, flaky/scaly skin or who has one of the above skin conditions.
How Often Can You Use It: Generally, you should apply to the affected areas one to three times a day (or as directed by your physician). Unless the treatment area is on the hands, remember to wash them immediately after using the product to not inadvertently treat the skin on the hands.
Works Well With: Products with Urea 40 should be used alone.

What Is Urea?

To put it simply, urea is a by-product of bodily waste, like sweat and urine when it’s found in its natural state, that is. “Urea is a natural-occurring by-product of protein metabolism in our livers. Synthetic urea is manufactured for skincare use,” explains Engelman. Much like hyaluronic acid—another humectant and popular skincare ingredient that our bodies already produce in small amounts—all skin already contains urea. However, when used in skincare products, urea is manmade, and the amount of the substance used in items like urea creams and gels will vary from item to item.

In addition to urea’s humectant properties, which attract moisture from vapors in the air and retain it into or under the skin's surface, Thornfeldt explains that urea molecules have a keratolytic effect. Keratolytic substances moisturize by breaking down keratin, which binds skin cells together, essentially removing that rough top layer to allow moisture to reach deep down. This can be incredibly helpful for anyone looking to shed dead, dry skin from the surface of their complexions and is available either over-the-counter or with a prescription.

Why Your Skin Might Love It

In products, it acts as a humectant moisturizer ingredient, holding onto water and keeping the skin hydrated. It also regulates the composition of skin, and acts as an exfoliant to help remove dead skin. Need more benefits? It can also be anti-itching and antimicrobial!

Benefits of Urea 40 For Skin

Adds intense moisture: When used on the skin (be that in a moisturizer, ointment, or other topical treatment), urea is offered in various concentrations, and each one is formulated to target different issues. Low doses of urea are usually labeled urea 2 or urea 10, with the number signifying the percentage of urea in the product at hand. Higher concentrations, like urea 40, are used to add an intense amount of moisture to the skin, making it ideal for treating dry, rough skin, along with skin conditions that consistently yield such symptoms.
Sloughs away dead skin: “Urea can penetrate thick skin, such as foot calluses, and is excellent for cracked feet,” says Engelman. The breaking down of dead skin also makes urea 40 great for treating eczema, psoriasis, and corns.

Anti-fungal: “Urea is often used in creams to treat specific foot conditions, particularly those that are fungal in nature." A thick layer of the cream can combat fungus on or around the nails and may even soften the surface of thick fingernails and toenails. For this, Thornfeldt indicates urea in high concentrations. "Urea improve the delivery of other biologically active molecules in the skin such as anti-fungal/yeast medicines. It does this by being hydrophilic and a lipid barrier disruptor at concentrations above 12 percent."

Side Effects of Urea 40

In terms of side effects associated with Urea 40, Engelman lists “burning, itching, irritation, or skin break down in rare cases” to be among the most common. If you notice irritation after using Urea 40 cream, you may want to talk to your doctor about lowering the dose or reducing the application times. To get the best results from Urea 40 cream, take extra care to avoid getting any into your eyes, nose, and mouth, or anywhere near your groin area when you apply it to your skin and don’t apply Urea 40 to broken skin or cuts.

How to Use a Urea 40 Cream

First thing’s first: Before you start applying this stuff to your skin, you’re going to want to find the correct dosage of urea to treat your exact skincare concerns, which can prevent possible side effects from occurring. Using products that contain a low amount of urea will, predictably, produce milder results but can be ideal for anyone looking to simply add moisture to extra-dry areas of their skin or treat a mild case of athlete’s foot. If you’re looking for a more highly concentrated urea solution to treat a condition like eczema, it’s best to talk to your doctor, who can point you in the direction of a product that’s best suited to target your troubles. The most commonly used urea creams above 10 percent span somewhere within the urea 20 to urea 40 range.

Whatever the dosage you and your doctor decide is right for you, application is usually recommended twice a day, unless your doctor says otherwise. To target especially rough areas of the body, like cracked heels, you can lock in moisture with urea 40 and a simple DIY mask of sorts. “Apply to the cracked or dry area then cover with a cloth, like a sock, to protect and lock in moisture,” suggests Engelman. Urea 40 shouldn’t be used as an all-over body or facial moisturizer and should generally only be applied to areas where extreme dryness is found—like elbows, knees, and feet.2

Patch testing is a good way to figure out how you’ll react to Urea 40 in your skin. Apply a small amount of the product to a clean area and follow initial reactions or changes for the first 24 hours.

Where To Find It

Look for urea in moisturizers and serums. Hand creams and foot treatments commonly include high concentrations of urea to soften calloused skin, but at lower concentrations urea is also great for the face.

Urea only!

Note: Some preservatives will have the word “urea” as part of their name (e.g. diazolidinyl urea, imidazolidinyl urea), but don’t have any of the same effects as urea. Make sure you look for “urea” on its own in an ingredient list!

Anyone looking to hydrate or moisturize their dry skin has likely run the gamut when it comes to finding the right lotion or cream to get the job done. But what if you have a thick layer of dry skin that just won’t seem to budge? Enter: Urea 40, a skincare ingredient usually sold as a cream, lotion, or ointment. The main ingredient is surprise, urea (which is delivered at a concentration of 40 percent). Other, milder urea creams are available in lower concentrations—like Urea 10 and Urea 20—and even smaller traces of urea are found in some skincare products designed to hydrate skin.

The Takeaway

When it comes to Urea 40, this product is best left for people looking to treat exceptionally dry skin, like cracked heels, corns, or calloused skin. If you have a skin condition that has you battling dry skin consistently, like eczema or psoriasis, Urea 40 might be a good option for treating rough, itchy complexions, especially during flare-ups. Anyone simply looking for a good moisturizer, however, would probably benefit from a lower dose of urea or a hydrating cream or ointment that contains urea as an ingredient in addition to others.