Vitamin C Serum Formulation with Perfect C

You are correct that Perfect C (Ascorbyl Tetraisopalmitate) is generally easier to work with and more stable than L-Ascorbic Acid. However, as the staff mentioned, these two forms of Vitamin C have different solubility properties, which is why you cannot directly substitute Perfect C into a formula designed for L-Ascorbic Acid, such as the Vitamin C E Ferulic kit.

• L-Ascorbic Acid (Vitamin C Ultra-Fine): This is a water-soluble form of Vitamin C. It is highly effective but is known for its low stability, especially when dissolved in water and exposed to air, light, or heat. It requires a low pH (2.0-4.0) for optimal absorption and stability. The separation you observed in your L-Ascorbic Acid batch after leaving it outside the refrigerator is likely due to this inherent instability and potential lack of proper stabilizers or preservation in your specific mixture.
• Perfect-C™ (Ascorbyl Tetraisopalmitate): This is an oil-soluble form of Vitamin C. It is highly stable and absorbs well into the skin because it is oil-based. Formulating with Perfect C requires an oil or silicone base and potentially an emulsifier if you want to incorporate a water phase to create a cream or lotion. The original Vitamin C E Ferulic kit formula, designed for water-soluble L-Ascorbic Acid, does not contain the necessary oil phase or emulsifiers to properly incorporate Perfect C.

Fixing the Separated L-Ascorbic Acid Batch

The staff's suggestion to add Light Cream Maker™ or Pro Polymer™ to your separated L-Ascorbic Acid batch is a good approach to try and salvage it.

• Light Cream Maker™ is an oil-in-water emulsifier and thickener that works without heat and can handle up to 20% oil. It can help bind the separated layers together into a more stable cream or cream-gel texture.
• Pro Polymer™ is primarily a gel maker for water-based formulas but can also help create a creamy texture in water+oil formulas and has good electrolyte resistance. Adding it can help thicken and stabilize the mixture.

By incorporating one of these ingredients, you can potentially re-emulsify or thicken the separated mixture, making it usable again, although its long-term stability might still be compromised compared to a properly formulated and preserved product.

Importance of Phenoxyethanol

You asked if Phenoxyethanol (Extra Pure) is necessary. Yes, it is highly recommended, especially for any cosmetic product containing water. Phenoxyethanol is a preservative that helps prevent the growth of bacteria, yeast, and mold. Without a preservative, a water-containing product can quickly become contaminated, leading to spoilage, loss of efficacy, and potential skin irritation or infection. While refrigeration can slow down microbial growth, it does not eliminate the need for a preservative for products intended for regular use over time. Phenoxyethanol is considered a safe and effective preservative, though it is more effective against bacteria than fungi and is often used in combination with other preservatives for broad-spectrum protection.

In summary, while Perfect C is a great ingredient, it requires a different formula base than the Vitamin C E Ferulic kit. Your L-Ascorbic Acid separation issue is likely due to its inherent instability in water. Adding Light Cream Maker or Pro Polymer can help fix the texture, and using a preservative like Phenoxyethanol is crucial for the safety and shelf life of any water-based cosmetic product.