Adjusting Your Eye Makeup Remover Formula

Your current formula is effective at removing waterproof makeup, which is great! The stinging indicates an irritation issue that needs to be addressed for eye safety and comfort.

Potential Causes of Stinging

• pH Level: The most common reason for eye stinging from cosmetic products is a pH that is significantly different from the natural pH of tears (which is around 7.4). Even ingredients considered mild can cause irritation if the overall formula pH is too acidic or too alkaline.
• Ingredient Concentration: While ingredients like Butylene Glycol and Polyaminopropyl Biguanide are used in eye products, using them at higher concentrations (like 10% Butylene Glycol and 1% Polyaminopropyl Biguanide in your formula) could potentially cause sensitivity or stinging for some individuals, especially in the delicate eye area.
• Specific Ingredient Sensitivity: Although Poloxamer 184 and Poloxamer 124 are specifically noted as non-irritating to the eyes and suitable for eye makeup removers, individual sensitivities can sometimes occur. However, this is less likely than pH or the other ingredients at their current levels.

Recommended Adjustments

To reduce stinging while maintaining makeup removal efficacy, consider the following steps:

1. Check and Adjust pH: This is the most crucial step. Measure the pH of your finished formula. Ideally, for an eye product, the pH should be adjusted to be as close as possible to the natural pH of tears, typically in the range of pH 7.0-7.4. You can use a dilute acid (like citric acid solution) to lower the pH or a dilute base (like sodium hydroxide solution) to raise it, adding drop by drop and checking the pH frequently until you reach the target range. Adjusting the pH alone often resolves stinging issues.
2. Slightly Reduce Preservative Concentration: If adjusting the pH does not completely eliminate stinging, consider slightly reducing the concentration of Polyaminopropyl Biguanide. While 1% is within the recommended range, reducing it slightly (e.g., to 0.8% or 0.5%) might help reduce irritation. However, it is critical to perform a challenge test on the adjusted formula to ensure that the lower preservative concentration is still effective at preventing microbial growth.
3. Slightly Reduce Solvent Concentration: If the above steps are not sufficient, you could try slightly reducing the Butylene Glycol concentration (e.g., to 8% or 9%). Butylene Glycol helps dissolve makeup, so reducing it too much might slightly impact the formula's effectiveness on waterproof products. Test this carefully.

The Poloxamers (Poloxamer 184 and Poloxamer 124) are key to the effectiveness of your formula on waterproof makeup and are designed to be non-irritating to the eyes. It is generally not recommended to reduce their concentration if you want to maintain the current cleansing power.