Serum Formulation Review and Recommendations

Here is a review of your two serum formulations, along with recommendations based on the ingredients and their typical usage:

Formula 1: Brightening and Dark Spot Reduction Serum

Your formula includes Alpha Arbutin, Vitamin B3 (Niacinamide), and Glucosamine, which is an excellent combination for targeting skin brightening, reducing dark/red marks, and improving overall skin tone. Allantoin is a good addition for soothing the skin.

• Alpha Arbutin (2%): This is within the recommended usage rate (0.2-2%) for effective skin brightening. The optimal pH range for Alpha Arbutin is 3.5-6.5.
• Vitamin B3 (Niacinamide) (4%): This is a good concentration within the recommended range (1-10%) for its benefits in reducing hyperpigmentation, strengthening the skin barrier, and controlling oiliness. Niacinamide works synergistically with Glucosamine for brightening. The optimal pH range is 4.0-7.0.
• Glucosamine (4%): This is within the recommended range (1-8%), and 4% is specifically recommended when combined with Niacinamide for skin brightening and improving skin hydration. It should be in a formula with pH 3-7.
• Allantoin (0.5%): The solubility of Allantoin in water at room temperature is approximately 0.5%. Therefore, 0.5% is the maximum amount that will dissolve clearly at room temperature and is a suitable concentration for soothing and reducing irritation. The recommended usage range is 0.1-2.0%, with an optimal pH of 4-8.
• Phenoxyethanol (1%): This is a standard and effective concentration for preservation (recommended 0.5-1.0%). It is stable across a wide pH range (2-9).
• Ecocert (Organic Natural Thickener) (1%): Assuming this refers to a natural gum like Xanthan Gum, 1% is a typical usage rate for thickening water-based serums (recommended 0.1-2%). Xanthan Gum can be used in various pH environments.

Overall for Formula 1: The ingredient percentages are well-chosen and within recommended ranges for efficacy and stability. The combination of actives is suitable for your stated goals. The expected pH of 6-6.5 is within the effective range for all active ingredients.

Recommendation for Formula 1: To help prevent potential discoloration of Alpha Arbutin and maintain the stability of the formula, consider adding ActiveProtec™ OX at a concentration of 0.6%. This would slightly reduce the water percentage.

Formula 2: Softening, Moisturizing, and Healthy Skin Serum

Your formula focuses on hydration, soothing, and antioxidant benefits with Apple Stem Cell Extract, Green Tea Extract, Cucumber Extract, and Natural Moisturizing Amino Acids.

• Apple Stem Cell Extract (5%): This is at the higher end of the recommended usage rate (0.5-5%), which is suitable for providing antioxidant and potential anti-aging benefits. It should be added in the final step below 40°C and at pH 3.5-6.5.
• Green Tea Extract (5%): This is also at the higher end of the recommended usage rate (1-5%), providing strong antioxidant and anti-inflammatory properties, and helping to control oiliness. It should be added in the final step below 40°C and at pH 4.0-6.5. It is sensitive to light and metal ions.
• Allantoin (0.5%): Same as Formula 1, 0.5% is the maximum soluble amount in water at room temperature and is effective for soothing. Optimal pH is 4-8.
• Phenoxyethanol (1%): Standard and effective preservation at 1%. Stable at pH 2-9.
• Ecocert (Organic Natural Thickener) (1%): Assuming Xanthan Gum, 1% is a typical usage rate for thickening.
• Cucumber Extract (4%): This is within the recommended usage rate (3-5%) for its soothing and hydrating properties. Avoid heat over 50°C and use at pH 5-7.
• Natural Moisturizing Amino Acids (3%): This is within the recommended usage rate (0.5-5%) for providing hydration and supporting the skin's natural moisturizing factors. Optimal pH is 6-7.

Overall for Formula 2: The ingredient percentages are appropriate for achieving the desired effects of hydration, soothing, and antioxidant protection. The expected pH of 6-6.5 is within the effective range for most active ingredients, though some are more stable at slightly lower pH. The mixing instructions for Apple Stem Cell Extract and Green Tea Extract (adding in the final step below 40°C) are important.

Recommendations for Formula 2:

• To help protect the Green Tea Extract from degradation by metal ions, consider adding ActiveProtec™ OX at a concentration of 1%. This would slightly reduce the water percentage.
• Store the finished product in an opaque container to protect the light-sensitive Green Tea Extract.
• Avoid including Vitamin E in this formula, as it can affect the stability of Green Tea Extract.

pH Considerations for Both Formulas

Based on the optimal pH ranges of the ingredients, both formulas are likely to be slightly acidic to neutral. Your expectation of a pH around 6-6.5 is plausible and falls within the effective range for most of the active ingredients in both formulas. It is crucial to measure the pH of your finished serums and adjust if necessary to ensure optimal efficacy and stability of the ingredients.

Allantoin Usage

Regarding the appropriate amount of Allantoin, the recommended usage rate is 0.1-2.0%. However, its solubility in water at room temperature is limited to about 0.5%. Therefore, using 0.5% is appropriate for a clear, water-based serum stored at room temperature. If you were to store the product in a cooler environment (6-8°C), the maximum soluble amount in water is lower, around 0.2%. Your use of 0.5% is suitable for a room-temperature serum.

Both of your formulations are well-designed with appropriate ingredient selections and concentrations for your skin concerns. Implementing the recommendations regarding ActiveProtec™ OX and storage for Formula 2 will further enhance their stability and effectiveness.