Wait until you read this: "Oral administration of 1,000 mg a day of melatonin to five adults for 25 to 30 days resulted in drowsiness being noted as an adverse effect. There were no severe and/or irreversible impacts on clinical parameters (blood pressure, heart rate, ECG, serum chemistry, urine analysis) in these people." Source: Nordlund JJ, Lerner AB. The effects of oral melatonin on skin color and on the release of pituitary hormones. J Clin Endocrinol Metab. 1977