Zinc Sulfate for Melasma Treatment

Based on the information available, Zinc Sulfate has been researched for its use in treating melasma.

Here's a breakdown of the information regarding its use and concentration:

• Effectiveness: Research indicates that a 10% concentration of Zinc Sulfate solution applied topically helped reduce melasma by nearly 50% over a 3-month period.
• Usage Rate & Regulation: While research suggests effectiveness at 10%, the regulatory limit for Zinc Sulfate in cosmetic products is not more than 1%. If you use a concentration higher than 1%, the product must be registered as a drug and cannot be sold as a cosmetic.
• Irritation: Your observation about potential irritation above 5% is valid, and higher concentrations are more likely to cause skin reactions. The regulatory limit of 1% for cosmetics helps ensure safety and minimize irritation risks for general cosmetic use.

Therefore, while 10% showed efficacy in a study, for a cosmetic cream formulation, you should use Zinc Sulfate at a concentration of not more than 1% to comply with regulations and minimize the risk of skin irritation. If you require a higher concentration for potentially greater efficacy, the product would need to be formulated and registered as a drug, not a cosmetic.