Combining Ethyl Ascorbic Acid and Perfect-C™ in a Serum

You are planning to create a serum using two different forms of Vitamin C derivatives: Ethyl Ascorbic Acid and Perfect-C™ (Ascorbyl Tetraisopalmitate), each at a concentration of 10%.

Based on the product information:

• Ethyl Ascorbic Acid is a water-soluble Vitamin C derivative. It is highly stable and easy to mix in the water phase of a formulation. The recommended usage rate is 1-10%, with 3% typically recommended. Its effective pH range is 3.5-6.0.
• Perfect-C™ (Ascorbyl Tetraisopalmitate) is an oil-soluble Vitamin C derivative. It is also highly stable and should be mixed in the oil phase or during the cream-making process. The recommended usage rate is 1-10%, with 5% typically recommended. Its effective pH range is 5.0-5.5.

Feasibility of Combination

Combining a water-soluble and an oil-soluble ingredient requires a specific type of formulation. A simple water-based or oil-based serum will not work for both. To incorporate both Ethyl Ascorbic Acid and Perfect-C™ effectively, you would need to create an emulsion (like a lotion or cream) or potentially a biphasic serum that allows both phases to be present and mixed before application.

Concentration and Potential Irritation

You propose using 10% of each ingredient, resulting in a total concentration of 20% Vitamin C derivatives.

• While the recommended maximum usage rate for each ingredient individually is 10%, combining them at this high level results in a significant total concentration.
• Both derivatives are generally considered less irritating than L-Ascorbic Acid. However, a total concentration of 20% is quite high for facial skin and could potentially be too strong or cause irritation, especially for individuals with sensitive skin.
• The recommended typical usage rates are lower (3% for Ethyl Ascorbic Acid and 5% for Perfect-C™), which are effective concentrations for achieving benefits like whitening and anti-aging with less risk of irritation.

Compatibility

Both ingredients mention that they should not be used with Vitamin B3 (Niacinamide) or Zinc PCA in the same formula.

Conclusion

It is technically possible to formulate a product containing both Ethyl Ascorbic Acid and Perfect-C™ by creating an emulsion or biphasic system. However, using 10% of each, totaling 20%, is a very high concentration. While some skin types might tolerate it, it significantly increases the risk of irritation compared to using lower, typically recommended concentrations (like 3-5% of each or a combined total of 5-10%).

It is generally advisable to start with lower concentrations when combining potent active ingredients and observe how your skin reacts before considering higher percentages.