Serum Formulation Feedback: Stability, Whitening, and Preservation

Thank you for your inquiry regarding your serum formulation. We have reviewed the formula and your questions and provide the following feedback:

1. Ingredient Adjustments:

   • As the staff mentioned, your formula contains Zinc PCA, which is an electrolyte. Light Cream Maker™ (1%) may be sensitive to electrolytes and could affect the stability or texture. We recommend replacing Light Cream Maker™ with Pro Polymer at 1-1.3% for better electrolyte tolerance. Alternatively, if you prefer to use Light Cream Maker™, you may need to increase its concentration to 2-2.5% to achieve adequate viscosity and stability in the presence of electrolytes.
   • The concentrations of other active ingredients like Galactomyces Ferment Filtrate (35%), Vitamin B3 (4%), Witch Hazel + Allantoin (10%), Rice Vitamin (2%), Zinc PCA (1%), MSM (2%), and GlucoBright™ (3%) are generally within effective ranges for their stated benefits (moisturizing, anti-inflammatory, skin barrier, oil control, gentle whitening). No major adjustments are strictly necessary for these based on typical usage rates, but you can fine-tune based on desired feel and performance after testing.

2. Whitening Effect:

   • The formula contains Vitamin B3 (Niacinamide) and GlucoBright™ (Acetyl Glucosamine), both of which contribute to skin brightening and help reduce uneven skin tone gently. As the staff indicated, this formula is expected to improve skin brightness and give a healthy glow. However, it is not designed to achieve significant "pale" whitening or effectively reduce stubborn dark spots and hyperpigmentation.
   • If your goal is stronger whitening or reduction of dark spots, you would need to incorporate more potent whitening agents such as Activated Resorcinol or Tranexamic Acid, as suggested by the staff.

3. Preservation with 1,2-Hexanediol:

   • Yes, 3% 1,2-Hexanediol, especially when combined with 0.5% Mild Preserved™ (Ethylhexylglycerin), should provide sufficient preservation for a serum packaged in a vacuum pump bottle for commercial sale. 1,2-Hexanediol acts as a preservative booster and humectant. The vacuum pump packaging also helps minimize microbial contamination during use.
   • However, it is absolutely crucial to maintain high standards of cleanliness and hygiene during the manufacturing process and ensure that all packaging materials are properly sanitized before filling. Good Manufacturing Practices (GMP) are essential for product safety and stability when selling commercially.

4. Other Recommendations:

   • pH Adjustment: Ensure the final pH of the serum is appropriate for the ingredients, particularly Niacinamide, which is most stable between pH 5-7. Adjusting the pH might be necessary after all ingredients are added.
   • Stability Testing: Before commercial launch, conduct comprehensive stability testing (e.g., accelerated aging, freeze-thaw cycles) to ensure the formula remains stable in terms of appearance, texture, pH, and microbial load over its intended shelf life in the chosen packaging.
   • Sensory Testing: Evaluate the texture and feel of the serum. The combination of ingredients and the chosen thickener will influence the final sensory experience. Adjusting the thickener percentage (within the recommended range) can help achieve the desired feel.
   • Ingredient Quality: Ensure all raw materials are cosmetic grade and sourced from reputable suppliers.

Overall, this formula contains a good blend of ingredients targeting moisturizing, anti-inflammatory, barrier support, and oil control benefits. The gentle whitening effect is a nice addition, but manage expectations regarding strong dark spot reduction unless more potent actives are added. Pay close attention to the thickener choice/percentage and strict hygiene during production for stability and safety.