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What is melatonin? Why do we need it?

Melatonin is a natural hormone produced by the pineal gland, located deep within the brain. Its main purpose is to regulate the human body clock and help bring about sleep. Levels of melatonin fluctuate over time; lower melatonin levels are found during the day, while the highest melatonin levels are present in the body during the night.

Melatonin is associated with the sleep cycle in humans. Several double-blind, controlled studies have shown that melatonin reduces the time people need to go to sleep and improves the quality of a person's sleep. It can also reduce the effects of jet lag and help people recover their energy levels.

Melatonin may also work on a variety of other conditions. Some studies have shown that melatonin supplements can reduce the incidence of cluster headaches and tension headaches in people with sleep disorders. Test-tube studies suggest that melatonin can inhibit the production of breast cancer cells and increase survival rates in people with lung cancer and brain cancer. In addition, it may effectively treat fibromyalgia and a pediatric disorder called Angelman's syndrome.

How much melatonin should I take?

Normally, the body secretes melatonin for several hours per day in healthy people. For people who have a melatonin deficiency or trouble sleeping, most practitioners recommend between 1 and 3 milligrams of a melatonin supplement each night, taken one to two hours before bedtime. People with cancer often take large amounts of melatonin - up to 20 milligrams per night. Melatonin should not be taken during the day, and should only be taken under the supervision of a licensed health care provider.

What forms of melatonin are available?

Melatonin is available in some foods, but only in trace amounts. Synthesized melatonin supplements are available at some health food stores. However, in many countries, melatonin supplements can only be obtained through a doctor's prescription.

What can happen if I take too much melatonin? Are there any interactions I should be aware of? What precautions should I take?

Melatonin supplements have been associated with a wide range of side-effects, ranging from drowsiness and disorientation, to decreased sperm counts and sperm quality, to headaches and abdominal cramps. As a result, melatonin should not be taken by the following people: women who are pregnant or breastfeeding, people diagnosed with depression or schizophrenia, people diagnosed with autoimmune diseases (such as lupus), people with neurological disorders, and people with fibromyalgia. Diabetics should take melatonin supplements only under the care and supervision of a licensed health care provider.

Melatonin may also interact with certain medications, particularly chemotherapy drugs and medications used to treat breast cancer. As such, melatonin uptake should be monitored closely by any patients taking these or other medications.

As always, make sure to consult with a licensed health care provider before taking melatonin or any other dietary supplement or herbal remedy.


  • Haimov I, Laudon M, Zisapel N, et al. Sleep disorders and melatonin rhythms in elderly people. BMJ 1994;309:167.
  • Hughes RJ, Sack RL, Lewy AJ. The role of melatonin and circadian phase in age-related sleep maintenance insomnia: assessment in a clinical trial of melatonin replacement. Sleep 1998;21:52-68.
  • Lewy AJ, Bauer VK, Cutler NL, et al. Melatonin treatment of winter depression: a pilot study. Psychiatr Res 1998;77:57-61.
  • Shamir E, Laudon M, Barak Y, et al. Melatonin improves sleep quality of patients with chronic schizophrenia. J Clin Psychiatry 2000;61:373-7.
  • Zhdanova IV, Wurtman RJ, Wagstaff J. Effects of a low amount of melatonin on sleep in children with Angelman syndrome. J Pediatr Endocrinol Metab 1999;12:57-67.
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