Formulation Troubleshooting: Undissolved Hyaluronic Acid and Precipitation

Based on the ingredients and mixing method you provided, the issues with undissolved 8D Hyaluronic Acid and precipitation are likely due to two main factors:

1. 8D Hyaluronic Acid Dissolution: 8D Hyaluronic Acid is a gel-like form of Hyaluron that dissolves well in water. However, to ensure complete dissolution and proper gel formation, it is recommended to disperse the powder in purified water at a low temperature (e.g., in the refrigerator) before adding other ingredients. Adding the powder or gel directly to room temperature water without proper hydration time can lead to clumping and incomplete dissolution.

2. Precipitation due to pH: Your formula contains several ingredients that are acidic or perform best within specific pH ranges. Notably, Liquid Azelaic™ (Potassium azeloyl diglycinate) is water-soluble within a pH range of 5-11. If the overall pH of the formula drops too low (below 5), the Azelaic Acid component may precipitate out of the solution. Other acidic ingredients like Wrinkle-Fill™ (Acetyl-Tyrosine), Liquid Salicylic Acid, and DMAE (SkinTight MD™) Liquid, when combined, can significantly lower the formula's pH, impacting the solubility and stability of pH-sensitive ingredients, especially Liquid Azelaic™ used at a high concentration (10%).

Recommended Revised Mixing Procedure:

To address these issues, I recommend adjusting the mixing order as follows:

1. Hydrate 8D Hyaluronic Acid: Disperse the 8D Hyaluronic Acid powder in the purified water (40% portion) and let it hydrate fully, preferably by soaking in the refrigerator for several hours or overnight until a smooth gel is formed. Stir occasionally.
2. Dissolve Other Water-Soluble Powders: In a separate container, dissolve the other water-soluble powder ingredients (Panthenol, GlucoBright™, Safe-B3™, Wrinkle-Fill™, Tranexamic Acid, 4MSK, and Saccharomyces Lysate Extract) in a small portion of the remaining purified water. Stir until completely dissolved.
3. Combine Water Phases: Add the dissolved powder mixture from step 2 to the hydrated 8D Hyaluronic Acid gel from step 1. Mix thoroughly until homogeneous.
4. Add Liquid Ingredients: Gradually add the liquid ingredients one by one, mixing well after each addition: DMAE, Matrixyl 3000, Argireline, Repair Activator™, Liquid Azelaic™, Liquid Salicylic Acid, and Dimethyl Isosorbide (DMI).
5. Add Preservative: Add Mild Preserved Eco™ and mix until fully dispersed or dissolved (may require stirring for about 5 minutes).
6. Check and Adjust pH (Recommended): Measure the pH of the final mixture. If it is below 5, carefully consider adjusting the pH upwards using a dilute Sodium Hydroxide solution, adding drop by drop while mixing and checking the pH, until it is within a suitable range for most ingredients (e.g., pH 5-7). Be aware that pH adjustment can sometimes affect viscosity or stability.

Adjusting the mixing method to allow for proper hydration of 8D Hyaluronic Acid and carefully combining ingredients will help resolve the dissolution and precipitation problems in your formula.