Melatonin is a naturally occurring hormone scientists believe “sets the clock” in everyone’s cycle of sleeping and waking. It increases in the evening as sunlight diminishes and decreases in the morning as sunlight returns.

Melatonin is produced by an organ at the base of the brain called the pineal gland. The production of melatonin declines with age, and supplemental melatonin is most helpful in mature persons with decreased melatonin levels.

If you have to have a cup of coffee to jump start your morning, you probably don’t have enough melatonin. The brain’s natural supply of melatonin is reduced by caffeine, benzodiazepines (tranquillizers such as Librium and Valium), and beta-blockers for controlling high blood pressure.

If you have been taking melatonin for insomnia and you haven’t been getting the expected results, the problem may be a shortage of magnesium. Especially if you also experience delayed sleep, cluster headaches, depression, chronic fatigue syndrome, or asthma, a minimal dosage of magnesium (with calcium, copper, and zinc) may be what is required to help melatonin reset your body clock for restful sleep.