The Food and Drug Administration has issued a warning letter to HBB LLC, the maker of Lazy Larry relaxation brownies, citing that the melatonin used in its product has not been deemed as a safe food additive. Furthermore, the FDA says it can seize the company’s brownies, should HBB continue to make and sell them.

Melatonin is a naturally occurring hormone in the human body and aids in sleep regulation. Melatonin supplements are only lightly regulated by the FDA, and therefore, the makers of melatonin-containing products claim they are not subject to regulatory agency approval, unless their products contain a brand-new ingredient. In large quantities, melatonin can cause the body’s central nervous system to slow and ultimately lead to breathing problems. Generally, however, melatonin causes people to become extremely tired and slightly nauseous.

Up until last month, Lazy Larry brownies were marketed and sold as, “Lazy Cakes,” but the name was changed in order to further establish the product as a supplement and to appease its critics. However, the FDA’s warning letter indicates the agency is not completely satisfied with simply name change for the product.