Foot Cream Formulation with Lactic Acid and Urea

Based on your questions and the previous response, here is the information regarding your proposed foot cream formulation:

Your proposed formula:

• Sodium Lactate 5%
• Urea 10%
• Lactic Acid 5%
• Water
• Preservative

This combination is suitable and can be used together.

Regarding your specific questions:

• Gluconolactone: You do not need to include Gluconolactone in this formula because Lactic Acid (an AHA) is already present, which helps to lower the pH. While Lactic Acid may not maintain the pH stability above 7 as effectively as Gluconolactone over the very long term, it is perfectly fine for a product intended for use within approximately 3 months, provided it is not stored in hot conditions.
• Trying ingredients separately: It is acceptable to combine Sodium Lactate, Urea, and Lactic Acid as proposed in your formula. There is no requirement to test Sodium Lactate and Urea separately before combining them in this formulation.

Additional Recommendation:

• Alternative AHA: Glycolic Acid is suggested as an alternative to Lactic Acid. It may offer better results for softening hard skin and is less sticky than Lactic Acid, although it is typically more expensive.
• Consistency: It is highly recommended to formulate this mixture into a cream consistency rather than a liquid. A cream is generally much easier and more pleasant to apply to the feet and dry areas.

This formulation should help to soften cracked and dry skin on the feet.