Mixing Urea Cream and High-Concentration AHA: Safety for Daily Use

Mixing skincare products, especially those with high concentrations of active ingredients like 20% Urea cream and 88% AHA (Lactic Acid), requires caution.

In your proposed 9:1 ratio (9 parts 20% Urea cream + 1 part 88% AHA), the resulting mixture would contain approximately 18% Urea and 8.8% AHA.

While both Urea and AHA are beneficial for dry, rough skin, combining them at these relatively high concentrations for daily use might be too potent for many skin types.

Urea at 18% is a strong keratolytic (exfoliant), and 8.8% AHA is also a significant concentration for daily leave-on use. The combination can lead to excessive exfoliation, irritation, redness, burning, and increased sensitivity to sunlight.

Furthermore, mixing finished products can affect their stability, pH, and overall efficacy in unpredictable ways. The pH of the final mixture is crucial for AHA effectiveness and skin safety, and simply mixing might not result in an optimal or stable pH.

Therefore, using this specific mixture daily might not be safe for everyone and could cause skin issues.

It is generally recommended to use products that are professionally formulated with appropriate concentrations of active ingredients. If you wish to use both ingredients, consider:

• Using the products separately at different times of the day or on different days.
• Looking for a professionally formulated product that contains both Urea and AHA at concentrations suitable for daily use.
• Starting with much lower concentrations if you are experimenting (though mixing is still not ideal).
• Always perform a patch test on a small area of skin before applying to larger areas.
• Consulting a dermatologist for personalized advice, especially if you have sensitive skin or a skin condition.

In summary, the proposed 9:1 mixture resulting in ~18% Urea and ~8.8% AHA is likely too strong for safe daily use for most people and carries risks of irritation and instability.