Melatonin.

Melatonin, a hormone produced by the pineal gland, appears to help regulate the sleep-wake cycle. With further study and clinical experience, it may become an accepted therapy for insomnia. Although melatonin preparations are available without prescription in health food stores and pharmacies, their potency, purity, safety and effectiveness cannot be assured. Until large clinical trials provide further information about melatonin's efficacy, adverse effects, drug interactions and effects on various disease states, melatonin products should be used with the understanding that many questions about their safety remain unanswered.