Serum Formula Assessment

Your formula provides a good combination of moisturizing ingredients (Hyaluronic Acid, Rice Vitamin) and a skin barrier support ingredient (Cerasoft) in a light serum base. The percentages used for each ingredient are within the typical recommended ranges for cosmetic formulations, suggesting it should be effective for hydration and improving skin feel. The inclusion of Disodium EDTA helps to stabilize the formula by chelating metal ions in the water, and Mild Preserved Eco provides preservation. Magnesium Sulfate is also included, which the Silky Serum Base Plus description notes can help improve formula stability. Overall, the formula appears well-balanced for a moisturizing serum.

Answers to Your Questions

1. Is this formula okay? Any additional recommendations?
   The formula is generally okay and provides a solid base for a moisturizing serum. The ingredient choices and concentrations are appropriate for their intended functions. For additional recommendations, you might consider adding an antioxidant (if targeting anti-aging) or a soothing agent (if targeting sensitive skin), depending on the specific skin concerns you wish to address. Always perform stability testing on your final product.

2. Should Mild Preserved Eco be mixed in water or Silky Serum Base Plus without a blender?
   Mild Preserved Eco can dissolve in water, but the description indicates it requires blending for about 5 minutes to become clear. Without a blender, dissolving it completely clear in the water phase might be challenging and require extensive stirring. It can also be dispersed in oil. The product description recommends adding it in the last step when the formula has a gel or cream texture. Given your formula is a serum, you can try dissolving it in the water phase with thorough stirring before combining phases, or adding it to the final serum and stirring very vigorously until it is as dispersed as possible. Dissolving it in the water phase first might be easier to ensure even distribution without a blender.

3. Can RO water with EDTA be used instead of DI water?
   Yes, according to the description for Disodium EDTA, it is suitable for use with reverse osmosis (RO) water or clean plain water when distilled water is not available. The purpose of adding Disodium EDTA is precisely to chelate ions present in these water sources, preventing them from interfering with the formula and helping with stability.