Formulation Feedback: Vitamin C and Lycopene Water Essence

Thank you for sharing your formulation. It's great that you've observed the stability of Vitamin C with the addition of Lycopene.

You've correctly identified the main issues: the very low pH (1) and the slight stickiness.

Analysis of Your Formula

• High Vitamin C Concentration: Your formula uses L-Ascorbic Acid at 15%. L-Ascorbic Acid is inherently acidic, which explains the low pH of 1. High concentrations can also contribute to the sticky texture you're experiencing.
• Lycopene: Lycopene is a powerful antioxidant and can help protect Vitamin C from oxidation, which is beneficial for stability. Your usage rate of 5% is within the typical recommended range (1-10%). The ratio of Vitamin C to Lycopene isn't the primary cause of the pH or stickiness issues; these are mainly due to the high concentration and nature of L-Ascorbic Acid itself.
• pH Level: A pH of 1 is too low for cosmetic application and can cause significant skin irritation. For L-Ascorbic Acid to be effective and safe for skin, the optimal pH range is typically between 2.0 and 4.0. The FDA requires cosmetic products applied to the skin to have a pH of at least 3.5.

Recommendations to Address pH and Stickiness

To improve the formula's pH and texture while maintaining efficacy, consider the following adjustments, similar to the staff's suggestions:

1. Reduce Vitamin C Concentration: Lowering the percentage of L-Ascorbic Acid will help increase the pH and reduce stickiness. A concentration of 10% is still highly effective for brightening and is a common level used in stable formulations.
2. Incorporate Solvents/Carriers: Adding ingredients that help dissolve and carry the Vitamin C can improve texture and penetration. Options include:
   • Ethoxydiglycol: This acts as a solvent and carrier and can help reduce stickiness. The staff suggested 5%, but please note that current regulations limit Ethoxydiglycol usage to not more than 2.6% in leave-on skin products like a water essence. Using it within this limit can still be beneficial.
   • Ethyl Alcohol: Can help reduce stickiness but should be used sparingly (e.g., 5% as suggested by staff) as it can be drying to the skin.

Suggested Approach

A balanced approach could involve:

• Reducing the Vitamin C (L-Ascorbic Acid) to 10%.
• Adding Ethoxydiglycol (up to 2.6% for a leave-on product) and/or a small amount of Ethyl Alcohol (e.g., 5%) to improve texture and aid penetration.
• Adjusting the water percentage accordingly.
• Keeping Propylene Glycol, Glycerin, and the preservative at appropriate levels.
• Maintaining Lycopene at 5% for its antioxidant benefits.

Remember to always check the pH of your final formulation and adjust it to be within the safe and effective range (ideally 3.5-4.0 for L-Ascorbic Acid) if necessary, although reducing the Vitamin C concentration should help raise it significantly from pH 1.

Performing stability testing on the adjusted formula is also crucial to ensure the Vitamin C remains potent over time.