Urea
Urea is a naturally occurring compound found in the skin’s natural moisturizing factor (NMF) and is widely used in skincare for its hydrating, exfoliating, and skin-softening properties. It is a humectant, meaning it helps attract and retain moisture in the skin, making it an essential ingredient in formulations designed for dry, rough, and sensitive skin. Urea is also a keratolytic agent, meaning it helps break down and remove dead skin cells, making it particularly effective for treating conditions like eczema, psoriasis, keratosis pilaris, and calloused skin.
One of urea’s standout benefits is its dual-functionality—at lower concentrations (2-10%), it acts primarily as a humectant, deeply hydrating the skin and reinforcing the skin barrier. At higher concentrations (above 10%), urea provides gentle chemical exfoliation, helping to dissolve the bonds between dead skin cells and smooth rough patches. This makes it a key ingredient in products designed for very dry, cracked, or thickened skin, such as foot creams and hand balms.
Urea is often found in moisturizers, serums, and medical-grade creams formulated for compromised or dehydrated skin. It is especially effective when combined with ceramides, hyaluronic acid, or glycerin, which further support skin hydration and barrier repair. Its non-irritating and skin-conditioning properties make it a safe choice for most skin types, though individuals with very sensitive or broken skin should start with lower concentrations to avoid potential stinging.
In addition to its hydrating and exfoliating effects, urea has been shown to enhance the absorption of other active ingredients, making it a valuable component in therapeutic and dermatological formulations. Regular use of urea-based products can help improve skin texture, relieve dryness, and promote smoother, healthier-looking skin, making it an essential ingredient in skincare for those dealing with severe dryness, rough patches, or barrier dysfunction.
Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula CO(NH2)2. This amide has two amino groups (–NH2) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid.
| |||
| |||
| Names | |||
|---|---|---|---|
| Pronunciation | urea /jʊəˈriːə/, carbamide /ˈkɑːrbəmaɪd/ | ||
| Preferred IUPAC name
Urea | |||
| Systematic IUPAC name
Carbonic diamide | |||
Other names
| |||
| Identifiers | |||
3D model (JSmol)
|
|||
| 635724 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| DrugBank | |||
| ECHA InfoCard | 100.000.286 | ||
| E number | E927b (glazing agents, ...) | ||
| 1378 | |||
| KEGG | |||
PubChem CID
|
|||
| RTECS number |
| ||
| UNII | |||
CompTox Dashboard (EPA)
|
|||
| |||
| |||
| Properties | |||
| CO(NH2)2 | |||
| Molar mass | 60.06 g/mol | ||
| Appearance | White solid | ||
| Density | 1.32 g/cm3 | ||
| Melting point | 133 to 135 °C (271 to 275 °F; 406 to 408 K) | ||
| Boiling point | decomposes | ||
| 545 g/L (at 25 °C) | |||
| Solubility | 500 g/L glycerol
50 g/L ethanol | ||
| Basicity (pKb) | 13.9 | ||
| Conjugate acid | Uronium | ||
| −33.4·10−6 cm3/mol | |||
| Structure | |||
| 4.56 D | |||
| ThermochemistryCRC Handbook | |||
Std enthalpy of
formation (ΔfH⦵298) |
−333.19 kJ/mol | ||
Gibbs free energy (ΔfG⦵)
|
−197.15 kJ/mol | ||
| Pharmacology | |||
| B05BC02 (WHO) D02AE01 (WHO) | |||
| Hazards | |||
| NFPA 704 (fire diamond) | |||
| Flash point | Non-flammable | ||
| Lethal dose or concentration (LD, LC): | |||
LD50 (median dose)
|
8500 mg/kg (oral, rat) | ||
| Safety data sheet (SDS) | ICSC 0595 | ||
| Related compounds | |||
Related ureas
|
Thiourea Hydroxycarbamide | ||
Related compounds
|
|||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |||
Urea serves an important role in the cellular metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals. Urea is Neo-Latin, from French urée, from Ancient Greek οὖρον (oûron) 'urine', itself from Proto-Indo-European *h₂worsom.
It is a colorless, odorless solid, highly soluble in water, and practically non-toxic (LD50 is 15 g/kg for rats). Dissolved in water, it is neither acidic nor alkaline. The body uses it in many processes, most notably nitrogen excretion. The liver forms it by combining two ammonia molecules (NH3) with a carbon dioxide (CO2) molecule in the urea cycle. Urea is widely used in fertilizers as a source of nitrogen (N) and is an important raw material for the chemical industry.
In 1828, Friedrich Wöhler discovered that urea can be produced from inorganic starting materials, which was an important conceptual milestone in chemistry. This showed for the first time that a substance previously known only as a byproduct of life could be synthesized in the laboratory without biological starting materials, thereby contradicting the widely held doctrine of vitalism, which stated that only living organisms could produce the chemicals of life.
