Three in 10 U.S. adults have trouble sleeping at least sometimes and one in every 10 experiences chronic insomnia, being unable to fall asleep at least three times a week, according to the National Institutes of Health. The most common sleep complaint at any age, insomnia affects nearly half of people age 60 or older. Melatonin is instrumental in regulating sleep cycles. Synthetic melatonin supplements are a widely used over-the-counter method of treating sleep disorders. However, results of research on melatonin's safety and efficacy have been mixed.
What It Is
Melatonin is a hormone that is produced by the pineal gland in the brain. Its production is stimulated by darkness and suppressed by light, suggesting that it is involved in the regulation of circadian rhythms--the 24-hour waking and sleeping cycle that corresponds roughly to day and night--as well as in regulating other body functions, according to MedlinePlus. Synthetic melatonin supplements are used most often to treat sleep disorders, but are also being used or investigated as remedies for other conditions.
Function
When the sun goes down, the pineal gland is turned on and begins producing melatonin, which is released into the blood. As the melatonin level in the blood rises one becomes less alert and sleep becomes more inviting. Melatonin levels in the blood stay elevated for approximately 12 hours and then fall back to low daytime levels. Daytime melatonin levels are barely detectable, says the "Sleep Disorders Sourcebook."
Uses
Melatonin is most commonly used to help insomniacs get to sleep and to help regulate the sleep cycles of people with disrupted circadian rhythms, such as travelers with jet lag and workers assigned to night shifts. There also is evidence that melatonin supplements can be helpful to people with low natural melatonin levels, including seniors--melatonin production decreases with age--and people with schizophrenia, according to the University of Maryland Medical Center.
Dosages
There currently is no standard recommended dose for melatonin supplements. The healthy human body normally produces about 0.3 mg per day. For insomnia, a usual dose ranges anywhere from 1 mg to 3 mg one hour before bedtime. For jet lag, 0.5 mg to 5 mg one hour prior to bedtime is common. Alternatively, 1 mg to 5 mg one hour before bedtime for two days before departure and two to three days after arrival at final destination is sometimes used. For children under age 15, doses should be kept to less than 0.3 mg; a dose of 1 mg to 5 mg could cause seizures in this group, according to the University of Maryland Medical Center. Substantially larger doses are sometimes used, under medical supervision, notes the "PDR for Nonprescription Drugs, Dietary Supplements, and Herbs."
Cautions
Some people experience vivid dreams or nightmares, or disrupted circadian rhythms, from taking too much of a melatonin supplement. Melatonin can cause drowsiness if taken during the day and could possibly interact with other medications such as antidepressants, antipsychotics, benzodiazepines, blood pressure medications, beta-blockers and others. So the University of Maryland Medical Center recommends that people taking other medications check with their doctors before taking melatonin supplements, and that pregnant and nursing women avoid taking melatonin.
Research
According to a monograph prepared by the Natural Standard Research Collaboration that is available through MedlinePlus, the strongest scientific evidence for the efficacy of melatonin involves treating jet lag. Substantial evidence also exists concerning its use to treat insomnia in the elderly, sleep disturbances in children with neuro-psychiatric disorders, and decreasing the time it takes healthy adults to get to sleep. Studies of using melatonin supplements for other purposes, such as treating attention deficit hyperactivity disorder, various cancers, the side effects of chemotherapy, glaucoma and high blood pressure have shown less conclusive results.
References
- National Institutes of Health: National Heart Lung and Blood Institute: Insomnia
- MedlinePlus: Melatonin
- "Sleep Disorders Sourcebook," Second Edition, Amy L. Sutton, Editor, 2005
- University of Maryland Medical Center: Melatonin
- "PDR for Nonprescription Drugs, Dietary Supplements, and Herbs," 31st Edition, 2010
Member Comments