I prefer taking melatonin no more that 2 or 3 times a week and at a dose of less than 2 mg. Sometimes taking a smaller amount, such as 0.5 mg, or even 0.3 mg, several hours before bed, on an empty stomach, works better than taking a higher amount, such as 3 mg, an hour or two before bed. However, each person is different and it may take trial and error to figure out the best dosage and timing. It would also be helpful to take a full week off every month or two. Melatonin works better taken on an empty stomach. Many people make the mistake of taking it after a meal, or taking it a half hour before bed expecting it to work similar to prescription sleep meds. A smaller amount, 2 to 4 hours before bed, on an empty stomach, works much better. There are reports of melatonin being an excellent antioxidant and perhaps having anti-cancer benefits. However, tolerance can develop if used frequently which is one of the reasons I suggest not using it nightly. Also, not enough long term studies are available to determine possible side effects if taken nightly several years in a row.