Eye Stinging from Cream Formula with Ascorbyl Palmitate 8%

Based on your formula and the feedback you've received, the ingredient most likely causing the severe eye stinging when sweat carries the cream into your eyes is Ascorbyl Palmitate (Vitamin C Ester) at the 8% concentration.

Here's why:

• Active Ingredient: Ascorbyl Palmitate is an active form of Vitamin C used for its antioxidant and potential collagen-stimulating properties. Active ingredients, especially at higher concentrations, can be irritating to sensitive areas like the eyes, even if well-tolerated on the skin.
• Concentration: You are using Ascorbyl Palmitate at the maximum recommended usage rate of 8%. While effective for skin benefits, this concentration increases the potential for irritation if it comes into contact with the eyes.
• Eye Sensitivity: The mucous membranes of the eyes are much more sensitive than skin. Ingredients that don't cause a reaction on the skin can still cause significant stinging or irritation if they get into the eyes.

The other ingredients in your formula are less likely to be the primary cause of this specific issue:

• LipidSoft Dry: This is an emollient designed to provide a dry, smooth feel. It is generally not known for causing eye irritation.
• Satin Mousse (Satin Cream Maker™): This is an emulsifier and thickener. While emulsifiers can sometimes cause mild irritation, severe stinging upon eye contact is less characteristic of this type of ingredient compared to a high concentration of an active.
• Phenoxyethanol: This is a preservative. While preservatives can sometimes be irritating, the "Extra Pure" grade you are using is specifically designed to minimize irritation risk, and eye stinging is not its typical reaction profile compared to the active ingredient.
• Purified Water: This is simply the base of your formula and does not cause irritation.

The fact that you experience stinging only when sweat carries the cream into your eyes further supports that it's related to the formula making contact with the sensitive eye area, and the high concentration of the active ingredient is the most probable trigger.

To address this issue, building on the staff's advice:

• Apply at Night: Using the cream only in the evening significantly reduces the chance of sweating causing the product to run into your eyes during the day.
• Careful Application: Be very mindful when applying the cream, keeping it well away from the immediate eye area (eyelids, under-eye close to the lash line).
• Consider Reducing Concentration: If applying only at night or avoiding the eye area isn't sufficient, you could consider reducing the concentration of Ascorbyl Palmitate in your formula (e.g., to 3-5%). This might reduce the eye irritation potential while still offering some skin benefits, although the efficacy on dark spots might be slightly less pronounced than at 8%.
• Explore Alternative Vitamin C Derivatives: As the staff mentioned, switching to a different, potentially less irritating form of Vitamin C could be an option, but this would require reformulating and testing to ensure desired results.

It's excellent that you are seeing positive results on your dark spots and skin texture! The formula seems effective for your skin; the challenge is just managing the potential for eye irritation due to the active ingredient's concentration and application near the eyes.