Formulating Lactobionic Acid Serum: Direct Mixing vs. Concentrated Solution

Yes, you can mix Lactobionic Acid powder directly with water and Glycerin to create a serum. There is no technical requirement to create a 90% solution first; in fact, adding the powder directly to your water phase is the standard and often easier method for formulation.

1. Direct Mixing vs. 90% Solution

• Direct Mixing: This is the recommended approach. You should dissolve the powder into the water and glycerin phase. For a beginner, the best order is: Water → Glycerin → Lactobionic Acid powder. Mix until fully dissolved. Mild warming can help, but is usually not necessary.
• 90% Solution Math: Your math is correct (9g powder + 1g water = 10g of a 90% w/w solution). However, a 90% solution is extremely concentrated, highly viscous, and difficult to handle. It is usually only prepared as a "stock solution" for industrial convenience and is not necessary for making a standard serum.

2. Formulation Guidance for Beginners

Since you are just learning to formulate, here are the key technical considerations for a Lactobionic Acid serum:

• Usage Rate: The recommended usage rate for Lactobionic Acid is 0.5% to 5%. Using more than 5% may cause skin irritation.
• pH Target: For an effective yet gentle exfoliating serum, aim for a pH of 3.5–4.2. Lactobionic acid is a Polyhydroxy Acid (PHA), which is naturally gentler and more moisturizing than AHAs like Glycolic Acid.
• pH Adjustment: Because Lactobionic Acid is quite acidic, it will significantly lower the pH of your water. You will likely need to adjust the pH upward using a base (such as a Sodium Hydroxide solution) to reach your target range.
• Preservation: Since your serum contains water and glycerin, it must include a preservative to prevent microbial growth. A suitable preservative option for this pH range is Mild Preserved™ COS.

3. Compatibility

• Glycerin: Glycerin (USP/Food Grade) is perfectly compatible with Lactobionic Acid and helps improve the serum's moisturizing properties and skin feel.
• Thickeners: If you want a "gel" serum texture, ensure your thickener is acid-stable. Some common thickeners (like standard Carbomer) will lose their viscosity at the low pH required for hydroxy acids.