Using Lactic Acid (AHA) Neutralized in Body Lotion/Serum

You can use Lactic Acid (AHA) Neutralized at 5% in a body lotion or serum for skin brightening and reducing marks. Here's guidance on your questions:

1. Daytime Use and Sun Exposure

Using products containing AHA, including Lactic Acid, increases your skin's sensitivity to the sun. Even though Lactic Acid Neutralized is designed to be less irritating, it still promotes exfoliation. Therefore, it is highly recommended to avoid direct sun exposure on the areas where the product is applied, especially during the day. Always use adequate sun protection (sunscreen) when using products with AHA, regardless of whether you apply them in the morning or evening. Using AHA products at night is generally preferred to minimize sun sensitivity risk.

2. Use in Serum and Thickeners

Yes, Lactic Acid Neutralized can be incorporated into a serum formulation. It is water-soluble and designed to be used in the water phase.

Regarding thickeners, while Lactic Acid Neutralized has a pH adjusted to be less harsh (around 4.0-4.5 at 10%), the final pH of your serum formulation will depend on all ingredients. For optimal AHA effectiveness and stability, the final product pH is typically kept in a slightly acidic range (ideally below 4.0 for maximum efficacy, though the neutralized version works at a higher pH). You should choose thickeners that are stable within the target pH range of your serum. Some common thickeners might lose viscosity at acidic pH levels, while others are specifically designed to be acid-stable. It's advisable to test the stability of your chosen thickener in your specific formula pH.