Melatonin

Melatonin is a naturally occurring hormone made by the pineal gland and plays a large role in circadian rhythms and sleep cycles.  Common uses for melatonin are jet lag, insomnia, sleep disorders, and sleep enhancement. There were very few adverse events reported with melatonin usage in patients. Some side effects are headaches, dizziness, nausea, and drowsiness.

For insomnia, a typical dose is 0.3-5 mg at bedtime.