Serum Formulation Feedback and Recommendations

Regarding your serum formulation aimed at skin whitening, acne reduction, and skin tightening, the original combined formula is not ideal. The staff recommendation to separate the formula into two distinct serums is a sound approach for better efficacy and reduced potential for irritation.

Combining a high concentration of Salicylic Acid, which is primarily for acne treatment and can be irritating, with multiple whitening and anti-aging ingredients in a single formula is generally not recommended. Salicylic Acid may require different application methods or frequencies compared to ingredients meant for continuous use. Mixing them can also increase the overall risk of skin irritation.

Recommended Formulas

Based on the staff's advice, here are the two recommended formulas:

1. Acne Treatment Formula:
This formula is designed to target acne and control oiliness, making it particularly suitable for oily and acne-prone skin types.

• Salicylic Acid (liquid form): 2%
• Vitamin B3: 5%
• Vitamin B5: 3%
• Pro Polymer: 1%
• Phenoxyethanol: 1%
• Water: Remaining percentage.

2. Whitening / Anti-aging Formula:
This formula combines ingredients for skin tightening, whitening, and antioxidant benefits, suitable for addressing concerns like dullness, dark spots, and loss of firmness.

• DMAE Liquid: 10%
• Vitamin B3: 5%
• GlucoBright: 3%
• Trans-White: 3%
• สารสกัดมะหาด (Oxyresveratrol): 2%
• Pro Polymer: 1%
• Phenoxyethanol: 1%
• Water: Remaining percentage.

Addressing Your Questions

• Adjusting for Different Skin Types: Separating the formulas helps cater to different skin types. The Acne Treatment formula is well-suited for oily and acne-prone skin. The Whitening/Anti-aging formula's base is generally suitable, but for dry skin, you might consider adding additional moisturizing ingredients like Glycerin or Hyaluronic Acid to the water phase, ensuring compatibility.

• pH Adjustment: Yes, pH adjustment is crucial for both efficacy and stability.

  • For the Acne Treatment Formula (with Salicylic Acid), the pH should be adjusted to a low range, typically pH 3-4, for Salicylic Acid to be effective.
  • For the Whitening / Anti-aging Formula, consider the optimal pH ranges for the ingredients: Vitamin B3 (pH 3-8, best 4-7), GlucoBright (pH 3-7), Trans-White (pH 3-8), Oxyresveratrol (pH 3-6.5), and Activated Resorcinol (if added) (pH 4.5-5.5). Aim for a compatible range, likely around pH 4.5-6.5.

• Achieving Desired Properties: By separating the formulas, each serum can be optimized to effectively target its specific concerns (acne in one, whitening/tightening in the other), increasing the likelihood of achieving the desired results compared to a single, less compatible blend.

• Adding Activated Resorcinol at 0.5%: Adding Activated Resorcinol at 0.5% to the Whitening / Anti-aging Formula is a good idea and is within the recommended usage rate for leave-on products (max 1%). It is a potent whitening agent that works well with Vitamin B3 and GlucoBright and can enhance the whitening effect. Remember it is light-sensitive (use opaque packaging) and works best at pH 4.5-5.5. Consider adding Disodium EDTA (around 0.2%) to help prevent discoloration.

Always perform stability testing on your final formulations before selling them.