How to Dilute Lactic Acid (AHA 88) Safely

Regarding your question about diluting Lactic Acid (AHA 88) and what to mix it with, based on the previous replies, here is the recommended approach:

Recommended Diluent

The correct substance to use for diluting Lactic Acid is distilled water. This is confirmed by the staff's advice. Mixing with honey or general cream is not recommended because it is difficult to accurately control the final concentration and, more importantly, the pH level, which is critical for safety.

Key Safety Guidelines

It is crucial to follow the safety guidelines for using AHA products on consumers, as outlined by the US FDA and mentioned by the staff:

• The final mixture's pH must be above 3.5.
• The concentration of the acid should not exceed 10%.
• Avoid sun exposure after application and use sun protection.

The Importance of pH Adjustment

While you can dilute the Lactic Acid 88% solution with distilled water to achieve a concentration of 10% or less, a solution made purely from Lactic Acid and water will be very acidic (have a low pH). The critical safety requirement is that the final pH must be above 3.5.

To ensure the pH is above 3.5, you typically need to use a pH adjuster to raise the pH of the diluted solution. A common pH adjuster for this purpose is Sodium Hydroxide solution.

Using Without a pH Adjuster

Since you mentioned you do not have a pH adjuster, and presumably do not have a pH meter to measure the final pH, it is highly risky to use the diluted Lactic Acid solution. Even at a 10% concentration, the pH will likely be below 3.5, which can cause significant skin irritation, burns, or other adverse reactions.

As the staff advised, using Lactic Acid outside the recommended concentration (<= 10%) and pH (> 3.5) should only be done under the supervision of a medical professional.

Therefore, while distilled water is the correct diluent, it is strongly recommended to adjust and measure the pH to ensure it meets the safety requirements before use. Without the means to do this, using the Lactic Acid carries significant risk.