83% less to 478% more than the dosage advertised on the label, based on these studies. Because the U.S. Food and Drug Administration (FDA) regulates melatonin

83% less to 478% more than the dosage advertised on the label, based on these studies. Because the U.S. Food and Drug Administration (FDA) regulates melatonin as a dietary supplement rather than a prescription drug, manufacturers have less strict oversight. Independently tested brands remain supreme. Often not even the expensive brands.