Urea in Skincare – Small Crystals for Intensive Hydration

Urea is one of the most useful ingredients for formulas designed for dry, rough-feeling skin.

Cosmetic urea is synthetically produced but chemically identical to the urea naturally present in human skin. It forms part of the skin’s Natural Moisturising Factor – NMF.

How much urea should you use?

As a general guide:

• 2–5% – everyday moisturising care
• 5–10% – dry and rough-feeling skin
• around 10% and above – more intensive care for thickened, rough areas

Formulating with urea

Urea is highly soluble in water but can be unstable in aqueous formulations.

Its degradation increases with temperature, and stability studies found good stability over approximately pH 4–8, with the lowest degradation in a lactate buffer at around pH 6.0.

For practical formulation:

• dissolve urea separately in water,
• add it during cool-down,
• preferably keep the temperature below approximately 40°C,
• target a final pH of around 5.5–6.0,
• check pH again during stability testing.

Urea Soft – 5% Urea Hand and Body Lotion

Ingredients for 100 g

Phase A

• distilled water – q.s. to 100%
• 3 g glycerin – 3%
• 2 g sodium lactate 60% – 2%

Phase B

• 10 g sweet almond oil – 10%
• 5 g shea butter – 5%
• 5 g Montanov 68 – 5%

Phase C

• 5 g urea – 5%
• 2 g D-panthenol 75% – 2%
• 0.5 g vitamin E – 0.5%
• 0.6 g Cosgard – 0.6%
• lactic acid – q.s. to pH 5.5–6.0

Method

1. Reserve approximately 10–15 g of the distilled water.
2. Combine the remaining water with glycerin and sodium lactate.
3. Prepare Phase B separately.
4. Heat Phases A and B to approximately 70–75°C.
5. Combine and homogenise thoroughly.
6. Dissolve the urea in the reserved water.
7. Cool the emulsion below approximately 40°C.
8. Add the urea solution, panthenol, vitamin E and Cosgard.
9. Measure and adjust the final pH to 5.5–6.0.
10. Top up with distilled water to 100 g if necessary.

Use

Apply to hands or body as needed, particularly after washing or showering.

Heel Comfort 10 – 10% Urea Foot Cream

Ingredients for 100 g

Phase A

• distilled water – q.s. to 100%
• 3 g glycerin – 3%
• 2 g sodium lactate 60% – 2%
• 0.2 g allantoin – 0.2%

Phase B

• 10 g sweet almond oil – 10%
• 6 g shea butter – 6%
• 5 g cocoa butter – 5%
• 5 g Montanov 68 – 5%

Phase C

• 10 g urea – 10%
• 2 g D-panthenol 75% – 2%
• 0.5 g vitamin E – 0.5%
• 0.7 g Cosgard – 0.7%
• lactic acid – q.s. to pH 5.5–6.0

Method

Prepare the heated emulsion from Phases A and B, reserving part of the water for the urea.

Dissolve the urea separately.

Below approximately 40°C, incorporate the urea solution and the remaining cool-down ingredients.

Adjust the final pH to 5.5–6.0.

Use

Apply a small amount to clean, dry feet, concentrating on heels and rough areas.

Ten percent urea can sting on severely cracked or irritated skin. In that case, discontinue use or choose the gentler 5% formula.

Urea: more is not always better

The ideal concentration depends on the purpose of the product.

For daily moisturising care, 5% may be entirely sufficient, while higher levels are better reserved for rougher, thickened areas.

With urea formulations, pH, temperature, preservation and stability testing are just as important as the percentage of urea itself.