Answers to Your Formulation Questions

Here are the answers to your questions regarding cosmetic ingredients:

1. Ethyl Ascorbic Acid vs. L-Ascorbic Acid pH

You are correct that Ethyl Ascorbic Acid does not require the very low pH levels that L-ascorbic acid does for stability.

• L-Ascorbic Acid: This form of Vitamin C is most stable and effective in acidic environments, typically requiring a pH range of 2.0-4.0. However, for cosmetic products applied to the skin, the FDA recommends a minimum pH of 3.5. L-ascorbic acid is prone to oxidation, especially in the presence of water.
• Ethyl Ascorbic Acid: This is a highly stable derivative of Vitamin C that is water-soluble. It is effective in a wider pH range, specifically 3.5-6.0. This makes it easier to formulate with compared to L-ascorbic acid, as it doesn't require such a low pH.

2. Ingredients for Dark Circles and Puffiness (REGU®-AGE, Orange Peel Extract, Caffeine)

These three ingredients work through different mechanisms to address dark circles and puffiness around the eyes:

• REGU®-AGE: This ingredient works by strengthening the skin around the eyes, making the tissue firmer. It helps reduce dark circles and puffiness by improving microcirculation and protecting the skin from UV damage and inflammation. Its mechanism involves hydrolyzed rice bran protein, soybean protein, and oxido reductases.
• Orange Peel Extract (Hesperidin Methyl Chalcone): This extract primarily works by stimulating blood flow. Increased circulation helps to reduce dark circles caused by poor blood flow or inflammation. It also has anti-glycation effects, helping to slow skin aging. It can cause a warming sensation due to increased blood flow.
• Encapsulated Caffeine: Caffeine is known for its ability to stimulate circulation and has anti-inflammatory and antioxidant properties. When applied topically, it can help reduce puffiness by constricting blood vessels and reducing fluid accumulation. Encapsulated forms, like Encapsulated Caffeine, can provide a slow release for continuous action.

Comparison and Combination:
Since these ingredients target different aspects of dark circles and puffiness (skin strengthening, blood flow stimulation, reducing fluid/inflammation), using a combination of them can potentially provide more comprehensive results than using just one. There isn't a single "best" ingredient among these; the optimal choice or combination depends on the specific cause of the dark circles or puffiness and the desired formulation properties. Combining ingredients with complementary mechanisms is a common strategy in cosmetic formulation.

3. Gentle Preservative for the Eye Area

For the sensitive eye area, a preservative specifically designed for gentleness is recommended.

• Eye Preserved™ (Polyhexamethylene Biguanide, PHMB): This preservative was developed for use in contact lens solutions, indicating its suitability for use around the eyes and for sensitive skin. It is gentle, has good heat resistance, is colorless and odorless, and does not contain formaldehyde. It is effective against a wide range of microorganisms but may have lower efficacy than some other preservatives, so maintaining high cleanliness during manufacturing is important. It is incompatible with anionic ingredients like Hyaluronic Acid and certain polymer-based thickeners.

Eye Preserved™ is specifically formulated to be gentle enough for the delicate eye area.