Modern dermatology considers the state of the epidermal barrier to be a fundamental aspect of overall health. One of the most critical components ensuring the integrity of this barrier is urea — an endogenous compound known in chemistry as carbamide, or carbonic acid diamide, with the formula CO(NH₂)₂. In the context of cosmetology, urea is not merely an ingredient but a biomimetic agent that plays a key role in maintaining moisture homeostasis. A true understanding of how to hydrate facial skin is impossible without a thorough analysis of the natural moisturizing factor (NMF), of which urea is an essential part. This report is dedicated to a detailed examination of urea's mechanisms of action, its role as an exfoliant, and practical recommendations for incorporating it into daily skincare.
What is urea
Urea is a colorless crystalline substance that dissolves readily in water and alcohol, yet remains insoluble in fats. It occurs naturally in the skin, accounting for approximately 7% of the total NMF mass. Its primary biological function is to retain water molecules within the stratum corneum of the epidermis — the very foundation of skin hydration at a physiological level. Because urea is hygroscopic, it draws moisture both from the deeper layers of the dermis and from the surrounding environment, keeping tissue elastic and supple. When its concentration in the epidermis drops below the critical threshold of 1%, the skin's protective function weakens, leading to xerosis, flaking, and irritation.
Urea for cosmetic use is produced through the synthesis of carbon dioxide and ammonia, which guarantees high purity and an odor-free result. The synthetic form is chemically identical to its natural counterpart but free of any impurities, making it an excellent choice for safe at-home skincare. Due to its high biocompatibility, urea rarely causes allergic reactions, which sets it apart from many other active ingredients.
Physiological causes of deficiency
As we age, urea levels in the epidermis naturally decline. The aging process is accompanied by the degradation of filaggrin — a protein that serves as a precursor to NMF components. This causes the skin to lose its ability to retain moisture, creating a need for external replenishment. Beyond aging, hormonal fluctuations — particularly the drop in estrogen during menopause — slow down sebaceous gland activity, creating a lipid deficit that further compromises hydration. A genetic predisposition to deficiencies in certain enzymes can also result in chronic dryness, where standard moisturizing approaches prove ineffective.
Environmental Aggressors
Environmental factors have a critical impact on skin hydration. Ultraviolet radiation (both UVA and UVB) breaks down the hydrolipid barrier, triggering premature aging and dehydration. In winter, dry indoor air combined with low outdoor temperatures draws moisture from the epidermis, causing cracking and roughness. Regular exposure to hard water, pool chlorine, and harsh detergents such as SLS strips away natural humectants. Once the barrier is compromised, even familiar products can cause a burning sensation, signaling the need to rethink your entire skincare strategy.
Medical causes of dry skin
Xerosis is often not merely a cosmetic concern but a manifestation of systemic conditions. In diabetes, elevated blood glucose causes significant fluid loss, leaving the skin vulnerable to infections. Patients with hypothyroidism frequently experience a sallow complexion and severe flaking on the elbows and knees. Atopic dermatitis and psoriasis involve a genetically impaired barrier function, where urea levels can be up to 80% below normal. In such cases, effective moisturization requires therapeutic emollients with a high concentration of carbamid.
How urea works in cosmetics
The mechanism of urea's action is unique in that it shifts depending on its concentration in the formula. At lower levels (up to 10%), it acts as a pure humectant, while at higher concentrations (above 10%), it takes on keratolytic properties. Thanks to its small molecular weight, urea penetrates deep into the stratum corneum rather than simply sitting on the skin's surface — it physically integrates into the skin's structure, simultaneously helping other active ingredients reach deeper layers. This makes it invaluable for enhancing the effectiveness of an entire skincare routine.
Key properties and biological effects
Urea offers a broad spectrum of therapeutic benefits. First, it provides intense hydration by retaining water in the intercellular space. Second, it has a pronounced antiseptic and antibacterial effect, which is particularly valuable for acne-prone skin. Third, carbamide relieves itching and the sensation of tightness, making it ideal for sensitive skin. It also stimulates cell regeneration, accelerating the healing of minor micro-damage.
If your skin has been craving that kind of deep hydration, Alis Hydrating Body Cream was formulated exactly for this — with urea at a level that softens and restores without overwhelming the skin.
Urea as an exfoliant
At higher concentrations, urea begins to break down the hydrogen bonds between keratin proteins in the stratum corneum. This loosens the "cement" holding dead skin cells together, allowing them to shed effortlessly. This form of exfoliation is far gentler than physical scrubs, as it does not damage healthy cells. Removing the layer of keratinized cells is, in fact, the first step toward effective moisturization — dead cell buildup acts as a barrier that prevents moisture from penetrating the skin. Exfoliation with urea leaves skin smooth and luminous while simultaneously delivering hydration to the deeper layers, making it one of the most effective at-home treatments with zero risk of mechanical trauma. If you want to combine chemical and physical exfoliation, Firming Body Scrub is an example of a formula where both approaches complement each other
Clinical applications and professional use
In clinical settings, urea at concentrations of 40% and above is used for the non-surgical removal of damaged nails or the treatment of severe hyperkeratosis. Dermatologists frequently prescribe such formulations to patients with psoriasis for rapid removal of keratinized plaques. In aesthetic dermatology, high-dose carbamide is used in foot peels — the well-known "exfoliating socks" — which require careful post-treatment moisturization, as intensive chemical action can leave the skin temporarily vulnerable. Professional recommendations for facial care typically avoid such high concentrations, focusing instead on delicate barrier support.
What is an exfoliant — in plain terms
The word "exfoliant" comes from the Latin for "to shed leaves." Simply put, it is a product that helps your skin get rid of the buildup of old, dead cells that accumulate on its surface. When these cells are not removed, the complexion looks dull and pores become congested. No moisturizer can penetrate through a layer of dead-cell "cement" — which is precisely why exfoliation is the essential first step in any hydration routine. Using urea as an exfoliant allows you to combine two processes in one: you gently clear away what no longer serves the skin while simultaneously delivering moisture to the deeper layers. This is one of the most effective at-home renewal methods available.
How to use urea in your skincare routine
Proper use of urea-based products ensures lasting results without adverse reactions. It is important to start with lower concentrations to allow the epidermis to adapt. When choosing products, check the ingredient list: urea should appear among the first five to seven ingredients for a genuinely therapeutic effect. Apply the product to cleansed, slightly damp skin to maximize carbamide's hygroscopic properties — this allows water molecules to be held within the stratum corneum for significantly longer.
Basic morning and evening routine
- Cleansing — Use gentle, alcohol-free gels or foams to avoid stripping the NMF. Soothing Body & Hand Wash Gel is a good example of a cleanser that respects the barrier rather than working against it.
- Toning — Choose toners with aloe vera or hyaluronic acid to prepare the skin.
- Serum — Apply a urea-based product (3–5%). This is the critical hydration step.
- Moisturizer — Seal in moisture with a cream containing ceramides or natural oils. Hydrating Body Cream or Nourishing Body Butter both work well at this stage — the cream for lighter daily use, the butter for nights when your skin needs more.
- Protection — In the morning, always apply SPF, as exfoliation increases the skin's sensitivity to UV radiation.
Best ingredient combinations
Urea works beautifully alongside other humectants. Pairing it with hyaluronic acid creates multi-layered hydration: hyaluronic acid holds water at the surface, while urea retains it within. Combining it with lactic acid enhances the keratolytic effect, which is beneficial for skin showing signs of hyperkeratosis. Urea also works synergistically with niacinamide, which calms inflammation and improves elasticity. Vitamins A and E further accelerate cell regeneration when added to the routine.
What not to combine with urea
Despite its safety profile, there are important limitations. High concentrations of urea (above 10%) should not be used simultaneously with potent retinoids or aggressive AHA/BHA acids, as this can compromise the skin barrier and cause significant irritation. Avoid applying it to broken skin or immediately after hair removal. In such situations, panthenol or allantoin are better choices until the epithelium has fully recovered.
Who is urea best for
Urea is a rescue ingredient for anyone whose skin suffers from chronic dehydration. It is ideal for mature skin, as it compensates for age-related moisture loss. Those with acne-prone skin will also find it a valuable ally, as it helps clear pores and combat bacteria without drying the face out. Low concentrations (2–5%) are particularly effective for restoring comfort after retinoid treatments that cause peeling. Urea is also recommended as part of the daily care routine for people with diabetes and atopic dermatitis — hands in particular tend to show the first signs of barrier breakdown, which is why a dedicated product like Hydrating Hand Cream can make a real difference in keeping cracks and discomfort at bay. For city dwellers, it offers additional defense against environmental pollutants — making it one of the most well-rounded skincare ingredients available.
