Re: Making AHA Body Wash

Hello,

Thank you for your detailed questions and for sharing your formulation attempt. Let's address your points based on the information provided:

Regarding your initial questions about making an AHA body wash with 5-10% glycolic acid:

• Yes, it is possible to make a body wash with glycolic acid at this concentration.
• Adjusting the pH to 3.5-4.5 is recommended. While adjusting to 5-6 is technically possible, AHA's exfoliating efficacy significantly decreases at higher pH levels. For effective exfoliation, a lower pH (ideally below 4) is needed.
• At pH 3.5-4.5, surfactants like Coco Betaine and Lauryl Glucoside will still maintain their cleansing ability. The staff confirmed this.
• Using a body wash with a pH in the 3.5-4.5 range is generally better for skin balance compared to high pH (>7-8) soaps, which can strip natural oils and cause dryness. The goal is gentle exfoliation during cleansing, which aligns with your preference for daily, gradual exfoliation.

Regarding your specific questions about your formulation attempt:

1. Weight Loss: It's highly unlikely that 5g of material disappeared due to dissolution. As Cosmeceutical7 explained, matter is conserved. The weight discrepancy is most likely due to residue left in the beaker or inaccuracies during the weighing process. Dissolving a solid in a liquid adds the weight of the solid to the liquid.
2. pH Adjustment Difficulty: You found it hard to raise the pH using Sodium Bicarbonate because it is a weak base, primarily used as a buffer to prevent drastic pH changes, not for making large adjustments from a very acidic solution like yours (with 10% glycolic acid). For significantly increasing pH in such a formula, a stronger base like Sodium Hydroxide (Lye) is typically used, but it requires extreme caution due to its corrosive nature. Your resulting pH of 3.3 is very acidic. While it's effective for AHA exfoliation, it's slightly lower than the 3.5-4.5 range suggested by the staff and might be more irritating for daily use on the body.
3. pH Meter Reading > 14: As Cosmeceutical7 mentioned, digital pH meters are usually calibrated for the 0-14 range. A reading above 14 is highly unusual for a cosmetic solution and suggests a potential issue with the meter calibration or the measurement technique.

In summary, making an AHA body wash is feasible, and a pH of 3.5-4.5 is suitable for both cleansing and exfoliation. Your formulation attempt resulted in a very low pH (3.3), which is effective for AHA but might be irritating. Adjusting pH significantly requires a stronger base than Sodium Bicarbonate, used with caution. Weight loss was likely a measurement issue.