What is melatonin? Melatonin is a sleep aid supplement that helps people sleep better and provides insomnia relief. Is melatonin bad for you? According to Dr. Castriotta, “low dose (1–3 mg) melatonin is safe and effective in certain circumstances in managing circadian rhythm disorders but is not a very good hypnotic.” A hypnotic drug is one that induces sleep. If melatonin helps you sleep, it is okay to take it every night for one to two months but after that stop and see how your sleep is, be sure to relax before bed. Some of the negative effects that melatonin causes are nausea, dizziness, headache, and drowsiness. It may also affect how you sleep if you discontinue using it. In conclusion, melatonin does not cause any harm to your body and you will be okay if you take it.