Urea is a byproduct of protein metabolism, which is excreted with urine and sweat. It also occurs in our skin as a natural moisturising factor. In cosmetics, its synthetic equivalent is used which is non-toxic and hypoallergenic. How does urea work and what are its properties and application?

Urea – production & properties

In 1828, Friedrich Wöhler, who was a chemist, isolated urea by chemical reaction with ammonium cyanate. In principle, this is not urea but carbonic acid diamide or carbamide – such terms are used by chemists and cosmetologists. The name ‘urea’ functions only in colloquial language.

Urea is a white, odourless and crystalline powder that dissolves in water and alcohol. For cosmetic purposes, it is obtained from ammonia and carbon dioxide.

Urea is a humectant, a substance that preserves moisture. In its natural form it belongs to the group of substances called NMF, which are responsible for the proper hydration of the skin. Initially, it constitutes about 7% in NMF group but decreases with age.

Urea has different properties depending on the concentration:

• 2% – urea stimulates the regeneration of the epidermis because it accelerates cell division in the granular layer of the skin. It is most often used in moisturising and regenerating creams,
• 3-10% – urea has moisturising and softening effect, it also increases levels of water in the stratum corneum. It is used in foot care products,
• 10% – urea has antibacterial effect. It is used in toners for acne-prone skin,
• 10-30% – urea breaks the hydrogen bonds of keratin and softens the skin also increasing its permeability. In addition, it helps active cosmetics or medicine penetrate into the skin,
• 30-40% – urea exfoliates the skin, which is why it is used it scrubs, exfoliating treatments and preparations for dry and callous skin, psoriasis and atopic dermatitis,

Urea – application

For many years, the name of this ingredient discouraged cosmetologists to use it in care. For this reason, the first cream with urea was made as late as in 1943. Today, urea is widely used in cosmetics for everyday use as well as in dermatological treatments.

Urea is a component of various cosmetic preparations:

• creams (for face, hands and feet),
• body lotions,
• ointments,
• emollients,
• face toners,
• hair shampoos and conditioners,
• toothpastes.

Due to its moisturising properties and the ability to store water in the deepest layers of the skin, urea effectively cares for dry and atopic skin. It also helps to treat skin disorders during menopause. In addition, urea improves the condition of the skin after sunbathing.

What’s more, urea also works well with other types of skin, for example sensitive and acne. Also, it helps with dandruff, dry knees, elbows and cracked heels.

Urea can be found under many different names on the label. The most common of these are:

• carbamide,
• carbamide resin,
• carbamimidic acid,
• carbonyl diamide,
• carbonyldiamine,
• isourea,
• 75 urea,
• pseudourea,
• ureaphil,
• ureophil,
• urevert.

However, the name is not as important as the concentration of urea which determines the properties of this ingredient.