Serum Formulation Review for Skin Nourishment + Whitening

Subject: Serum Formulation Review - "Skin Nourishment + Whitening"

Regarding your serum formulation for "Skin Nourishment + Whitening", here are the answers to your questions based on the ingredients and typical formulation practices:

• Question 1: Do I need to add more preservative?
  Yes, a preservative should be added. Given the 40% water content, it is recommended to include a preservative at a concentration of at least 1% of the water phase, which is 0.4% of the total formula. Recommended options include Mild Preserved Eco or Phenoxyethanol SA at 0.4%.

• Question 2: Which method is correct?
  Method A is the correct procedure for this type of formulation (Water in Silicone emulsion using SiliSolve Plus™). You should mix ingredients 9-12 (oil/silicone phase) first, then slowly add ingredients 1-8 (water phase) while blending with a high-speed mixer or homogenizer to ensure proper emulsification. Manual stirring is not sufficient.

• Question 3: Should I add an Anti-oxidant to help reduce the degradation rate of the ingredients?
  Yes, adding an antioxidant can help protect the ingredients from oxidation and extend the shelf life of the serum. Vitamin E Acetate at 0.1% is a suitable option to include.

• Question 4: Based on the ingredients, what skin type is it suitable for? Dry/Normal/Oily?
  Based on the ingredients, particularly the use of SiliSolve Plus™ which results in a light, water-in-silicone texture, this formulation is most suitable for normal to oily skin types.