What Is Melatonin and Its Effects?

Melatonin is a natural hormone produced by the pineal gland. This hormone is responsible for the regulation of our internal body clock which is also referred to as the “circadian rhythm“. The production of melatonin is influenced by the amount of light in the external environment. Darkness stimulates the production of melatonin while brightness produces the opposite effect.

Aside from the regulation of our biological clock, melatonin also aids in the regulation of other body hormones. In females, it regulates the timing of the releases of reproductive hormones which helps set the pattern of the menstrual cycle.

The most popular benefit of melatonin is its usefulness in the treatment of primary sleep disorders. The National Institutes of Health reports it as likely to be effective in treating sleep problems among children with autism and mental retardation. But over the years, scientists are uncovering more interesting benefits of this hormone. For example, almost two decades ago it was reported as a protector against glucocorticoid damage, and also as an enhancer of immune function. The following are just few of the benefits being uncovered among others below:

  •  Neuroprotection – Melatonin as a powerful antioxidant protects the molecules that are critical components of the nerves – lipids and proteins from damaging. It has the capacity to scavenge some of the most dangerous free radicals in the body including hydroxyl radicals and hydrogen peroxide. Unlike other antioxidants, melatonin easily diffuses into all cells, and even crosses the blood-brain barrier to protect the delicate brain. While it provides a strong protection against oxidative stress, melatonin declines as age advances leaving the elderly population more at risk to the development of degenerative diseases like Alzheimer’s disease and Parkinson’s disease.

Melatonin levels are particularly low in patients with Alzheimer’s disease. Nearly half of affected individuals suffer from sleep disturbances and “sundowning” – increased confusionagitation, and other symptoms in the afternoon and evening. Not surprisingly, melatonin supplementation benefits patients with Alzheimer’s disease by improving sleep and reducing late-day aggravation of symptoms. Melatonin has also been found to decrease cognitive deterioration in individuals with Alzheimer’s disease, possibly by protecting brain cells from the toxic protein, beta-amyloid (Cardinali, Furio and Reyes, 2005)

  •  Cancer Fighting – Studies have demonstrated the cancer-fighting ability of melatonin against a wide array of cancers notably breast and liver cancersnon-small-cell lung cancer and brain metastases from solid tumor.

Prostate cancer among the aging male population is recorded to be one of the most common malignancies and research have shown some promises as treatment with melatonin significantly reduced the number of prostate cancer cells. In a meta-analysis of 10 randomized, controlled trials to determine the effects of melatonin (alone or as an adjuvant treatment) on patients with various types of cancer, results showed that supplementation with melatonin reduced the relative risk of death at one year. In addition, there had been no reports of adverse effects. In other words, supplementation with melatonin in cancer treatment increases the likelihood of cancer survival.

However, there are other developments that change our understanding of this powerful hormone. For several years, melatonin has been at the forefront in treating jet lags. However, recent study shows that melatonin actually doesn’t really work to counter jet lag symptoms. Dr. Robert L. Spitzer, the study’s author and a psychiatrist at Columbia University in New York says “This study showed that the different doses of melatonin were no better than placebo at preventing jet lag symptoms,”

A word of caution – Melatonin is generally safe for adults taken in oral form. But it should be taken with extra caution for individuals with hypertensiondepressionseizure disorders and diabetes. It may not be safe for all children as it may interfere with the other hormones which could affect growth in the adolescent years.

The benefits of the melatonin hold promises in the treatment of debilitating and deadly diseases. Note however that science is still on the look-out for conclusive results about the potential therapeutic benefits of this hormone.



Agency for Healthcare and Research Quality. U.S. Department of Health and Human Services. http://www.ahrq.gov/clinic/epcsums/melatsum.htm

Life Extension Magazine. http://www.lef.org/magazine/mag2007/jun2007_nu_melatonin_01.htm

Medline Plus. http://www.nlm.nih.gov/medlineplus/druginfo/natural/940.html

University of Maryland Medical Center. http://www.umm.edu/altmed/articles/melatonin-000315.htm

The Jet Lag Story. “Latest Research says using Melatonin for jet lag doesn’t counter jet lag.” http://www.nojetlag.com/melatonin.html

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