Urea is a powerful humectant that is an essential part of the skin’s natural moisturizing factor (NMF). It draws moisture into the skin from the environment and helps retain it, which is why it’s a key ingredient in moisturizing skincare products. Urea also has keratolytic properties, meaning it can help exfoliate the skin and remove dead skin cells, which can improve the appearance of dry, rough, or scaly skin. The urea content of normal skin is nearly 1%, and contributes approximately 3-7% to the natural moisturizing factor. 

Here’s a more detailed explanation of how urea works for skin moisturizing: 

• Humectant: 

Urea acts as a humectant, meaning it can attract and hold moisture from the surrounding environment, drawing it into the skin. This helps to hydrate and soften the skin.  

• Natural Moisturizing Factor: 

Urea is a natural component of the NMF, which is a mixture of substances that helps maintain the skin’s water balance. By supplementing the NMF with urea, you can help boost the skin’s natural moisturizing abilities.  

• Keratolytic: 

At higher concentrations, urea can also act as a keratolytic, which means it can help break down and remove dead skin cells. This can help improve the appearance of rough, dry, or scaly skin.  

• Improves Barrier Function: 

Urea helps strengthen the skin’s natural moisture barrier, which is crucial for protecting the skin from external stressors and preventing moisture loss.  

• Other Benefits: 

Urea can also help improve the absorption of other skincare ingredients and can be used to treat various skin conditions, including eczema, psoriasis, and dry skin. 

Urea is used topically in the treatment of dry skin. At concentrations of 5-30%, urea 

promotes hydration of keratin and mild keratolysis in dry and hyperkeratotic skin. Urea increases the uptake of water by the stratum corneum, giving it a high water-binding capacity. Topically applied urea may also have an antipruritic effect. At high 

concentrations (e.g., 40%), urea is a protein denaturant. 

In summary, urea is a versatile ingredient that can be used to moisturize (around 2-5% is also capable of increasing hydration of the Stratum Corneum by 100% both by an osmotic effect due to its low molecular weight and for its ability to solubilize insoluble proteins), exfoliate, and improve the overall health and appearance of the skin.