Displaying 2 results of Melatonin Impurities Melatonin is a hormone produced naturally in the body that helps regulate sleep and wake cycles. However, during the manufacturing process of melatonin supplements, impurities can sometimes be introduced, such as byproducts from chemical reactions or contaminants from raw materials. These impurities can potentially affect the quality and safety of the supplement, and strict regulations are in place to limit their presence in melatonin products.