Ingredient

Urea

A moisturizer at low strengths and a scale-dissolver at high ones. The number on the tube changes what it does.
Dr. Schwarz, MD · Board-certified dermatologistLast reviewed September 8, 2026
Five white jars of 40% urea cream lined up, several also listing 2% salicylic acid

Start here

Urea is unglamorous, cheap, and the thing I reach for most often on rough, dry, scaly skin that ordinary moisturizer never quite fixes. The point to understand is that it does two different jobs at two different strengths — at 5% it pulls water into the skin, and at 20% and above it breaks apart the glue between dead surface cells so thick scale and callus come off. That is why people buy a 5% lotion for cracked heels and conclude urea does not work. I use it on shins, heels, elbows, the rough bumps of keratosis pilaris and thickened eczema patches, but it stings cracked skin, so calm the skin first.

— Dr. Schwarz, Board Certified Dermatologist

Key Facts

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Also calledCarbamide, urea, CH4N2O
TypeHumectant at low strengths, keratolytic at high strengths
Strengths sold2% to 10% for dryness, 20% to 40% for thick or scaly skin
UseOnce or twice a day, on the body more often than the face
Time to workA few days for softness, 2 to 4 weeks for thick scale
Prescription neededNo for most products in the United States

What It Is

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Urea is a small molecule the body makes when it breaks down protein. Most of it leaves in urine, which is where the name came from. The version in skincare is made in a lab from ammonia and carbon dioxide. Nothing on a shelf is taken from anyone. Skin makes its own urea and holds it in the outermost layer as part of natural moisturizing factor, the mix of small water-holding molecules that keeps the surface soft. People with eczema and with ichthyosis, an inherited scaling condition, have less of it. Applying urea tops up something the skin is short of. On labels it may appear as carbamide. In the United States it is sold without a prescription across the whole range, including 40%.

How It Works

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Urea has two jobs and the concentration decides which one you get.

Under about 10% it works as a humectant, drawing water into the outer layer of skin and holding it there. It also switches on some of the skin's own repair machinery, increasing filaggrin, the water channels called aquaporins, and the natural antimicrobial peptides in the surface layer. So it does more than sit on top like a sponge.

At roughly 20% and above it becomes keratolytic. Keratin, the structural protein of the skin surface, is held in shape by hydrogen bonds. Urea breaks those bonds, the packed dead cells lose their grip, and thick scale, callus and plugs shed. This is why 40% urea can soften a thickened nail enough for a clinician to lift the diseased part away without surgery.

A third effect explains a lot of ingredient lists. A softened, hydrated surface lets other things through, so urea is often paired with lactic acid, salicylic acid, a steroid or an antifungal.

The base matters as much as the number. A 10% urea ointment behaves differently from 10% in a thin lotion.

Here is where Urea acts in the skin, and what the others do instead.

About Urea
Compare
Skin basics
PULLS WATER INSTAYS ON THE SURFACELOOSENS DEAD SKINSEALS WATER INSEALS WATER INFILLS THE GAPSFILLS THE GAPS

A humectant draws water into the outer layer and holds it there. Skin holding more water is plumper and more flexible, and fine lines caused by dryness soften within minutes. Seal it with something on top or in dry air the water can simply evaporate away. Holds water and breaks down thickened keratin, which is why it suits rough, scaly skin.

Urea is small and water-loving. At low strengths it holds water in the outer layer; at high strengths it also breaks up the bonds between dead cells, which is why the same ingredient both moisturizes and softens thick skin.

These acids work at the surface. They break the bonds holding dead cells to each other, so the top layer sheds more evenly. Skin looks smoother and brighter, and anything applied afterwards gets in more easily.

An occlusive sits on the surface and slows water escaping. It adds nothing to the skin; it stops what is already there from leaving, which is why it works best over damp skin.

An occlusive sits on the surface and slows water escaping. It adds nothing to the skin; it stops what is already there from leaving, which is why it works best over damp skin.

Emollients are oils and lipids that sit in the spaces between the cells of the outer layer, the mortar between the bricks. They fill those gaps rather than covering them over, so skin feels smoother straight away, water stays in and irritants stay out.

Emollients are oils and lipids that sit in the spaces between the cells of the outer layer, the mortar between the bricks. They fill those gaps rather than covering them over, so skin feels smoother straight away, water stays in and irritants stay out.

The outermost layer, and the one every moisturizer is aiming at. It is dead — flattened cells stacked like bricks, with a mix of fats as the glue between them. That glue is what holds water in and keeps irritants out.

The outer layer, and the only one anything in a jar reaches. It renews itself constantly: a cell made at the bottom takes about a month to reach the surface and flake off. Most of what a skincare product does, it does here.

The living layer underneath, holding the blood vessels, the nerves and the collagen. It is where lasting change happens and it is hard to reach: most of what is sold for the skin never gets this far.

What It Treats

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Keratosis Pilaris

Keratosis Pilaris

Strong evidence

The single most useful thing for keratosis pilaris, because it does both jobs at once: it holds water in the dry skin and it breaks down the keratin plug. Use 10 to 20 percent on the arms or thighs most days, on damp skin after a shower. It stings a little on cracked skin, and the bumps return within a few weeks of stopping.

Dry Skin (Xerosis)

Dry Skin (Xerosis)

Strong evidence

The best choice for thick, scaly skin on heels, shins and elbows, because it softens and dissolves the scale as well as holding water. Ten to twenty percent for general dryness, forty percent for hard heel skin. It is the alternative to scrubbing, which removes the barrier along with the flakes. It stings on cracked or broken skin, so heal the cracks first.

Eczema

Eczema

Moderate evidence

A moisturizer with urea in it, for patches that have gone thick and leathery from years of scratching. 10% and above. It stings on raw or weeping skin, so it belongs to the dry, cracked stage rather than the sore one.

Not the Best For

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Seborrheic Keratosis

Limited evidence

A strong urea cream can soften and flatten the rough white growths that scatter over the lower legs, called stucco keratoses, if the roughness is what bothers you. It smooths the surface rather than removing the growth, and it has to be used continuously. It does nothing for thick, dark, stuck-on growths elsewhere.

Athlete's Foot

Athlete's Foot

Limited evidence

A urea or salicylic acid cream thins the hard scale on the sole so an antifungal can actually reach the skin underneath. It is a helper, not a treatment: on its own it does nothing to the fungus. It is worth adding for the dry moccasin pattern, where cream otherwise sits on top of the thickened surface.

Psoriasis

Psoriasis

Limited evidence

Softens hard, thickened skin and helps shift scale, which makes it useful on the palms, soles and the thickest plaques. Higher strengths work better here than the low ones sold for dry skin. It can sting on cracked skin, so it goes on intact plaques rather than open fissures.

Forms

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A row of Urea products sold as cream, photographed on white.
Everyday dryness
Cream
The most common form, usually 5% to 10%. Suits arms, legs and hands.
A row of Urea products sold as lotion, photographed on white.
Large areas
Lotion
Thinner and faster to spread over whole legs or a back. Usually a lower strength.
A row of Urea products sold as foam, photographed on white.
Fast absorbing
Foam
Sinks in quickly and leaves less residue, which makes it easier to use before dressing.
A row of Urea products sold as heel balm or ointment, photographed on white.
Feet
Heel balm or ointment
Thick and sealing, usually 25% to 40%. Made for skin that has gone hard rather than dry.
A row of Urea products sold as nail gel, photographed on white.
Thick or diseased nails
Nail gel
Around 40%, applied under a dressing to soften the nail plate. This is a clinician-directed use, not a home project.
Thick or diseased nails
Nail gel
Around 40% under a dressing to soften the nail plate. Clinician-directed, not a home project.

Strengths

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Strength matters more here than with almost any other ingredient. It is not a dial from weak to strong but a switch between two jobs. Choose by what the skin is doing, not how bad it feels.

WeakestStrongest
2% to 5%10%20%30% to 40%40% and above
Everyday moisturizer
2% to 5%
Adds water to dry skin. Comfortable on the face and on children's skin. It will not touch thickened areas.
Rough, dry skin
10%
The general-purpose strength for shins, arms and hands. Mostly a moisturizer, with a little softening.
Scale and bumps
20%
Where the keratolytic effect becomes obvious. The usual choice for keratosis pilaris, thickened eczema patches and scaling legs.
Callus and heels
30% to 40%
For skin that has gone hard. Keep to feet, elbows and knees — too strong for the face.
Nails, with a clinician
40% and above
Under a dressing, to soften a thickened or fungal nail so the damaged part can be removed.

Basics

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When to Apply
Once or twice a day, on skin still slightly damp after washing, which gives the urea water to hold. Sunscreen, other actives and makeup are unaffected, so timing is up to you.
How to Start
Start with the lowest strength that matches the problem and use it daily for two weeks before deciding. For thick heels, apply a high-strength balm at night under socks. For keratosis pilaris, 20% every day beats a stronger product used occasionally.
If It Irritates
Stinging is common on cracked or inflamed skin and usually means the strength is too high for how damaged the skin is. Drop down, or use a plain moisturizer for a week to let the surface close. Keep high strengths off the face, the groin and broken skin.
If It’s Not Working
Check the number. Most people who say urea did nothing used 5% on a problem that needed 20%. Then check how often you use it, because urea works while it is on the skin. For rough bumps, adding lactic acid is a reasonable next step.

What to Expect

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Days 1 to 3Weeks 1 to 2Weeks 2 to 4
Adjusting
Days 1 to 3
Skin feels softer almost immediately. A brief sting is common on cracked areas.
Working
Weeks 1 to 2
Roughness eases and flaking drops. Thick areas look less built up.
Judge it here
Weeks 2 to 4
Callus and scale should be visibly thinner. If a thickened area has not changed after a month of daily use, the strength is too low.

What to Avoid

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  • Urea fits easily into a routine It has no meaningful conflicts and does not make skin sun-sensitive.
  • Broken, cracked or weeping skin High-strength urea on an open crack stings sharply. Let the skin close first.
  • The face, at high strengths The 30% and 40% products are made for callus. On the face they are uncomfortable and unnecessary.
  • Groin, underarms and other thin folds Skin here is thin and moist, and keratolytic strengths are the wrong tool.
  • Scrubbing a high-strength area Urea already loosens the surface. Add a pumice stone and you take off more than you meant to.
  • The folklore urea is called unsuitable for the face, or something to space apart from retinoids, acids and vitamin C. Neither is true. Low-strength urea is an ordinary face moisturizer and it layers with everything. It is also not an exfoliating acid.

If You Stop

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Softness fades over a few days, and rough or scaly skin returns to its old state over one to three weeks. Callus rebuilds more slowly, over a month or two. Nothing rebounds. Skin does not become drier than it was, and there is no withdrawal effect. Urea is maintenance, not a course. Most people using it for keratosis pilaris, ichthyosis or persistently dry legs use it indefinitely, often dropping to a few times a week once the skin settles.

Ask Your Doctor

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If you are treating a thickened nail
Thickened or discolored nails have different causes, and the cause changes what helps. High-strength urea is only part of the answer.
If your cracked heels bleed or hurt
Deep splits can become infected and may need more than a moisturizer.
If your skin stings every time
Even at a low strength, that points to a barrier more damaged than it looks.
If you use a steroid cream on the area
Urea helps other ingredients through the skin, so a prescription steroid can act more strongly alongside it.
If you are treating a baby or young child
Small bodies absorb proportionally more, and the right strength is different.
If you are pregnant or breastfeeding
Ask the doctor managing your pregnancy before using high-strength urea over large areas.

How It Compares

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Five moisturizer bottles containing glycerin lined up on white, including a bottle of pure vegetable glycerin16:9 hero for Glycerin. Never cropped: the tone strip and the corner logo depend on the full frame.

Glycerin

Different job

A similar water-holding effect and cheaper, but it does nothing at all to thick scale or callus.

Lactic acid and ammonium lactate

The same

Comparable on scaling and rough skin, and better at loosening the surface at moderate strengths, but it stings more and can leave skin briefly sun-sensitive.

Paula's Choice 2% BHA exfoliant, La Roche-Posay Effaclar cleanser and a CeraVe psoriasis cream pumpLabeled cutaway diagram of a single skin pore, headed Salicylic Acid. The epidermis is a brick-textured band across the top and the dermis is pink below it, with a yellow oil gland at the base of the pore and a small cluster of bacteria inside it. A single dark navy callout line points into the top of the pore: decreases dead cells in pore. There are no other callouts, so the drawing shows one effect where the other ingredient diagrams show two or three.

Salicylic acid

Different job

On scale and plugged pores. Better inside oily pores, but it is oil-loving rather than water-loving, so it does not hydrate the way urea does.

Petrolatum and plain ointments

Different job

Better at sealing water in and safer on broken skin, but they add no water of their own and do nothing to thickened areas.

Ceramide moisturizers

Different job

Better for rebuilding a leaky barrier in eczema, less useful when the problem is a build-up of hard surface.

Myths

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  • "Urea in skincare comes from urine." It is made in a factory from ammonia and carbon dioxide. The molecule is the same one the body makes, which is why skin recognizes it, but nothing on a shelf is animal-derived.
  • "Urea is an exfoliating acid." It is not an acid and does not lower a product's pH. At high strengths it loosens the bonds between dead cells, which looks like exfoliation, but the mechanism differs and it brings no sun-sensitivity concern.
  • "You cannot use urea on the face." Low-strength urea is a very ordinary face moisturizer. It is the 30% and 40% callus products that belong on feet.
  • "Higher strength is always better." Higher strength is a different job, not a better version of the same one. A 40% product on normal dry skin does less than a 10% cream.
  • "It stops working after a while." Urea does not lose effect. Skin that seems to stop responding has usually improved, or is being treated less consistently.

Questions Patients Ask

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Is urea made from urine?

No. It is made in a factory from ammonia and carbon dioxide. It is chemically identical to the urea your skin already makes and stores in its outer layer, which is why skin recognizes it, but no part of the supply chain involves urine.

Which strength should I buy?

Match it to the problem, not to how uncomfortable the skin feels. Ordinary dryness needs 5% to 10%. Rough bumps on the arms and scaling legs need around 20%. Hard, built-up heels need 30% to 40%. Buying the strongest one for everything is the common mistake.

Will it help keratosis pilaris?

Usually, for the bumps. Urea at 10% to 20% daily flattens the rough texture over about a month. The color around each bump responds less well, and on deeper skin tones the brown marks often outlast the roughness, so a pigment treatment is sometimes added. The bumps return within a few weeks of stopping.

Does it make skin sensitive to the sun?

No. Unlike glycolic and lactic acid, urea does not increase sun sensitivity, so there is no need to keep it for nighttime.

Can I use it with a retinoid, vitamin C or an acid?

Yes, all of them, in the same layer if you like. Urea has no meaningful conflicts. If anything it helps the others get in, which can make a retinoid feel stronger for the first week.

Is it safe in pregnancy?

Very little is absorbed from ordinary strengths on ordinary areas, and urea has a long history of use. Still, check high-strength products over large areas with the doctor managing your pregnancy.

References

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