Formula Evaluation: AHA Gel Body Cream

Based on the ingredients and percentages provided, this formulation is generally usable, but there are important considerations regarding pH to ensure efficacy and stability.

Let's look at each ingredient:

• Disodium EDTA (0.1%): This acts as a chelating agent, helping to bind metal ions in water. This improves the stability and shelf life of the product, especially if using non-distilled water. The percentage used is within the typical recommended range (0.1-0.2%).
• Allantoin (0.5%): Known for its soothing and anti-irritant properties, Allantoin helps reduce skin irritation and supports tissue regeneration. The usage rate of 0.5% is within the recommended range (0.1-2.0%) and is soluble in water at room temperature. Allantoin is most effective in a pH range of 4-8.
• AHA (5%): Alpha Hydroxy Acids (AHAs) are used for exfoliation, helping to remove dead skin cells and improve skin texture. A 5% concentration is common for body products. For AHAs to be effective for exfoliation, the final product's pH typically needs to be low, generally below 4.
• Pro Polymer (1%): This ingredient acts as a gel maker or thickener, providing the desired texture for your cream. The usage rate of 1% is within the recommended range (0.5-5%) and should create a suitable gel consistency. Pro Polymer has good electrolyte resistance, but its performance at very low pH levels required for AHA efficacy should be tested.
• Glycerin (5%): A humectant that draws moisture into the skin, helping to keep it hydrated. 5% is a suitable concentration for moisturization and is well within the typical usage range (1-100%). Glycerin also helps dissolve other ingredients.
• Phenoxyethanol SA (1%): This is a broad-spectrum preservative (equivalent to Optiphen Plus), essential for preventing microbial growth and keeping the product safe. The 1% usage rate is within the recommended range (0.5-1.25%) for general products. This preservative is effective in a pH range of 2.0-6.0.

Key Consideration: pH Balance

The most critical aspect of this formula is managing the pH.

• For the 5% AHA to provide effective exfoliation, the final pH of the product should ideally be adjusted to a low level, typically between 3.5 and 4.0.
• However, Allantoin functions optimally in a pH range of 4-8. While it may still provide some benefit at a lower pH, its efficacy might be reduced.
• The preservative, Phenoxyethanol SA, is effective down to pH 2.0, so it will function correctly at the low pH required for AHA.
• The stability and viscosity provided by Pro Polymer should also be tested at the target low pH, as some gel makers can lose viscosity in acidic conditions.

Recommendation:

The formula is viable, but you will need to carefully adjust the final pH after all ingredients are mixed. Aim for a pH that balances the exfoliating efficacy of the AHA with the stability and performance of the other ingredients. It is highly recommended to perform stability testing on the final product at the adjusted pH to ensure the texture remains consistent and the ingredients remain effective over time.