Supplements: Melatonin

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Melatonin is an important hormone secreted by the pineal gland in the brain. Since its identification in 1958, studies have shown that melatonin actually regulates many of the other hormones in the body. These hormones control our circadian rhythm, the 24-hour patterns that our bodies respond to every day. The release of melatonin is stimulated by darkness and suppressed by light, so it helps control when we sleep and when we wake. Melatonin also controls the timing and release of female reproductive hormones, affecting menstrual cycles, menarche, and menopause. Overall levels of melatonin in the body also respond to the process of aging. Children have the highest levels of nocturnal melatonin; as adults age, their nocturnal melatonin levels get lower and lower, which means they go to sleep and wake up earlier, and may suffer from disrupted sleep patterns.


  • Jet lag. Melatonin is used to restore sleeping patterns and fatigue caused by cross time-zone travel.
  • Insomnia. Melatonin can restore more regular sleep patterns in those who suffer from insomnia as a result of low melatonin levels (that is, older people and some children with sleep disorders that may be caused by autism, epilepsy, Down syndrome, or cerebral palsy).
  • Cancer. Melatonin can help prevent and treat some cancers, particularly those that are related to hormones (for example, breast cancer, prostate cancer) and non–small cell lung cancer. It also greatly increases the effectiveness and lowers the side effects of some cancer drugs (for example, interferon and interleukin 2).
  • Depression. Melatonin may be beneficial in treating depression related to low melatonin levels (for example, seasonal affective disorder)
  • Preliminary studies show melatonin may be useful in treating multiple sclerosis, coronary heart disease, epilepsy, and post-menopausal osteoporosis; and in preventing sudden infant death syndrome.

Dietary Sources


Other Forms

Melatonin is available as tablets, capsules, and sublingual tablets.

How to Take It

There is no official dosage range for melatonin supplements. Different people will be more sensitive or less sensitive to melatonin. For those especially sensitive to it, lower dosages may work as effectively as the standard amount, while taking the standard amount or higher dosage could cause anxiety and irritability.

To treat insomnia, one dose of 3 mg an hour before bedtime is usually effective, although dosages as low as 0.1 to 0.3 mg may improve sleep for some people. If 3 mg a night is not effective after three days, try 6 mg one hour before bedtime. An individually effective dose should produce restful sleep with no daytime irritability or fatigue. For treatment of jet lag, take 5 mg of melatonin one hour before bedtime upon arrival at your destination, and take it for the first five days. Dosages for anticancer treatment may be much higher (10 to 50 mg per day). Do not take melatonin supplements long term without consulting your health care provider.


There are no known serious side effects to supervised melatonin use. Lack of sleep and insufficient exposure to darkness may suppress your body's natural production of melatonin. Some people may experience vivid dreams or nightmares when they take melatonin. Overuse or incorrect use of melatonin could disrupt circadian rhythms. Melatonin can cause drowsiness if taken during the day. If you experience morning drowsiness after taking melatonin at night, take less of it.

It may not be good for you to take melatonin if you have an autoimmune disorder, such as lupus or rheumatoid arthritis, or an immune system cancer, such as lymphoma or leukemia. If you are taking melatonin for depression, make sure you do so under your health care provider's care and advice. In some cases, melatonin can actually worsen the symptoms of depression instead of making them better.

If you take corticosteroids for anti-inflammatory or immune suppressive purposes (for example, you have had a transplant), use melatonin cautiously, and always under the supervision of your health care provider. Melatonin could interfere with fertility. Do not take it if you are pregnant or nursing.

Possible Interactions

Vitamin B12 changes the level of production of melatonin. If you have low levels of melatonin, you will often have low vitamin B12 levels as well. Taking vitamin B12 (1.5 mg of methylcobalamin per day) can help sleeping disorders because it increases melatonin production. Protein, vitamin B6, niacinamide, and acetyl carnitine all help your body produce melatonin. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, reduce melatonin production levels in the body, so it is best not to take these right before bedtime. Beta blockers also keep melatonin levels from rising naturally at night. Some antidepressants increase the levels of brain melatonin. Benzodiazepines, like Xanax and Valium, interfere with melatonin production. Alcohol and caffeine can also interfere with melatonin production, as can diuretics and calcium channel blockers.

This document contains information relating to general principles of medical care that should not in any event be construed as specific instructions for individual patients. The reader is advised to check product information (including package inserts) for changes and new information regarding dosage, precautions, and contraindications before administering any drug. No claim or endorsements are made for any drug or compound currently in investigative use. No responsibility is assumed by the publisher for any injury and/or damage to any person or property as a matter of product liability, negligence, or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in any material herein.

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Dietary supplements are not intended to treat, cure, or prevent any disease or illness, and the information regarding these products has not been evaluated by the U.S. Food and Drug Administration.

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Previously Published in OSA Today Reproduced by permission
Updated on: 02/01/10