Julian Whitaker, MD

Melatonin is a hormone produced by the pineal gland, a tiny structure embedded in the center of the brain that responds to light entering the eyes. As night falls and darkness encroaches, your melatonin level rises, peaking between 1:00 a.m. and 5:00 a.m., and then falling off. Melatonin regulates the circadian rhythms of sleeping and waking, as well as daily fluctuations in your body temperature, sense of hunger, energy, and mood. Melatonin production declines dramatically as we age, which may explain why sleep problems are so common among the elderly.

Taking melatonin at bedtime has been shown to facilitate deep and restful sleep and to help people with jetlag get back on a normal sleep schedule. However, with so much focus on melatonin as a sleep aid, its other benefits are often overlooked.

Melatonin Is One of Our Most Potent Antioxidants

According to Russel Reiter, PhD, Professor of Neuroendocrinology at the University of Texas Health Sciences Center at San Antonio and one of the world’s leading authorities on melatonin, melatonin is also a potent antioxidant.

Unlike most other free radical fighters, it is both fat- and water-soluble, so it protects all parts of the cell, including DNA. According to Dr. Reiter, melatonin is at least twice as effective at protecting fatty cell membranes as vitamin E, five times more powerful than glutathione in neutralizing highly damaging hydroxyl radicals, and 500 times better than DMSO at protecting cells from radiation. It also easily crosses the blood-brain barrier to protect the brain, which is exceptionally vulnerable to free radical damage.

The Cancer Connection

One of the most exciting areas of melatonin research is cancer. Whether it’s made in your pineal gland or taken in supplement form, melatonin is a potent antioxidant that protects cellular and mitochondrial DNA from mutations that give rise to, and propagate, cancer.

Evidence to support the cancer-melatonin link has been building for decades. Women who work night shifts—which radically repress melatonin production—have about a 50 percent increased rate of breast cancer. Conversely, people who are blind typically have above-average levels of melatonin and significantly lower cancer rates.

A recent study showed that melatonin-depleted blood stimulates the growth of tumors in animals, while melatonin-rich blood reduces tumor growth. David Blask, the lead researcher of this study explained that melatonin puts breast tumors to sleep at night, but in artificial light the “cancer cells become insomniacs.”

Melatonin may help prevent cancer, but can it treat the disease? Canadian researchers conducted a meta-analysis of 10 studies involving patients with tumors of the breast, lung, brain, kidney, and skin who took 10 to 40 mg of melatonin a day. They concluded, “The substantial reduction in risk of death, low adverse events reported, and low costs related to this intervention suggest great potential for melatonin in treating cancer.”


  • Maintain your melatonin levels, as noted above, by adhering to nature’s light/dark cycle as much as possible.
  • Take a vitamin/mineral supplement that contains 100 mg of B3 (niacin) and 75 mg of B6 (pyridoxine), as they facilitate the conversion of tryptophan to serotonin, the precursor of melatonin, as well as 500 mg of magnesium and 1,000 mg of calcium, which are also involved in melatonin production.
  • If you’re over 40, take supplemental melatonin, as needed, 30 minutes to an hour before retiring. If you’re traveling across time zones, take at bedtime in your destination to avoid jetlag. The average recommended dose is 1-3 mg. For patients with cancer, 10-40 mg, taken at bedtime, is a therapeutic dose.
  • Although melatonin is exceptionally safe, I also don’t recommend melatonin for people who are under 40, those taking steroid drugs, pregnant or nursing women, and people with severe allergies or autoimmune diseases. Melatonin is available in health food stores.


  • Harder B. Bright lights, big cancer. Science News. 2006 Jan 7;169(1):8–10.
  • Mills E, et al. Melatonin in the treatment of cancer: a systematic review of randomized controlled trials and meta-analysis. J Pineal Research. 2005 Nov;39(4):360–366.
  • Reiter, RJ et al. Melatonin, Your Body’s Natural Wonder Drug, 1995. Bantam Books, New York, NY.

Modified from Health & Healing with permission from Healthy Directions, LLC. Photocopying, reproduction, or quotation strictly prohibited without written permission from the publisher. To subscribe to Health & Healingclick here.

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