Melatonin is a fascinating human hormone, produced in the pineal gland of the brain. It
affects the body’s circadian rhythm and sleep patterns, and endocrine (hormone)
secretions. Synthesized from the amino acid tryptophan, it becomes serotonin as an
intermediate product. Its production is inversely related to the amount of light a person
gets, varies with age, and may be increased by meditation or music therapy. It is rapidly
inactivated, so that with lower doses (3 mg or less by mouth) one can drive or use
machinery 4-5 hours afterward. Use has been reported or studied in 30 conditions,
ranging from sleep disorders and disruptions, depression, seizures and other brain
conditions, to cancer and sunburn.
Sleep conditions have been studied the most, with varying conclusions. As is often true,
methodology, patient selection and product formulation vary, making overall conclusions
difficult. Although the measurable marker of sleep efficiency does not seem to improve
with melatonin, subjective reports of sleep quality, alertness, daytime sleepiness and
fatigue improve with use for jet lag, and the time it take to fall asleep (sleep latency) in
general insomnia. Sustained release preparations may be better for sleep maintenance, but
have not been sufficiently studied. Unfortunately, melatonin does not seem to yield
improvement in measurable markers for those working rotating or graveyard shifts; I
found no notation of subjective benefits for this use. Special needs children may have
benefits, but parents need to check with the provider for these specialized uses.
A prescription, sustained release preparation is being studied in France for the indication
of sleep. The only other common self medication situation in which melatonin is likely
effective is nicotine withdrawal.
Preliminary studies indicate potential benefits for those with migraine headaches, chronic
fatigue syndrome, and fibromyalgia, and insomnia caused by irritable bowel syndrome or
the medications propranolol and other beta blockers. A single low dose seems to increase
sexual behavior, though repeated high doses are inhibitory.
Melatonin apparently has immune modulatory, antioxidant and oncostatic (keeping
cancers from growing) effects; these are being investigated with respect to several
cancers, but also could negatively affect people on immune suppressant drugs.
Depression can be aggravated by use of melatonin, so even though there is some
evidence it may help sometimes, it is definitely NOT recommended until more is known.
People with diabetes, high blood pressure and seizure disorders also should avoid
melatonin.
Combining melatonin with ongoing use of anticoagulant and antiplatlet drugs,
benzodiazepines (valium family), immunosuppressants, luvox, nifediine and verapamil
should be approached cautiously, with the knowledge of your provider. Do not drink
alcohol with melatonin. Those younger than 20 years produce higher amounts of
melatonin, and chronic use of melatonin could cause problems; they should not take it
regularly.
Side effects in study patients are the same as placebo: daytime drowsiness(20%),
headache(8%) and dizziness(4%). The drowsiness is not significant at doses 3 mg and
lower. Many other side effects have been reported with a much lower incidence.
Most preparations contain synthesized melatonin; that from animal sources is not
recommended, as it may contain contaminants.
For INSOMNIA, doses of 0.3 to 5 mg at bedtime have been used; doses 3 mg or less
have minimal side effects of drowsiness the next day. The same size dose, taken at
bedtime on the arrival day at the destination seems to help JET LAG; this can be
continued 2 to 5 days. This works heading east more than 4 time zones, but not reliably
traveling west. For acute NICOTINE WITHDRAWAL, a single dose 0.3 mg orally 3 and
a half hours after smoking the last cigarette helped alleviate anxiety, restlessness,
irritability and craving for 10 hours; repeated doses have not been tested.
Many products contain a combination of melatonin with various herbs. Theoretically this
could help, but none have been well tested, and such combinations could just as easily
have more side effects.
Sources: Natural Medicine Comprehensive Database, accessed 12/8/09; Melatonin for
Treatment of Sleep Disorders, Evidence Report/Technology Assessment, number 108,
November 2004 (from the federal government Agency for Healthcare Research and
Quality