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Melatonin helps cancer patients sleep better

Melatonin helps cancer patients sleep betterInsomnia is common among cancer patients. Sleep medicine is associated with serious side effects, but research shows that the natural hormone, melatonin, may help improve the sleep quality of cancer patients in several different ways. Melatonin even has cancer-inhibiting mechanisms that deserve a closer look in terms of prevention and treatment.

Although melatonin is primarily known for its role as a sleep hormone, and many cancer patients suffer from insomnia and sleep disturbances, melatonin is not commonly used in cancer therapy. Therefore, a group of researchers from Karnataka Institute of Medical Sciences in India decided to conduct a double-blind study of melatonin’s ability to improve sleep quality among cancer patients with insomnia.

Insomnia is physically and mentally exhausting

Since the beginning of time, we humans have depended on a good night’s sleep to help us digest our food and recuperate physically and mentally. Nonetheless, sleep disturbances are common among the general population, not least among cancer patients. Insomnia leads to complications such as fatigue, poor concentration, irritability, impaired immunity, and problems with the blood sugar balance and digestion. Also, insomnia may exacerbate symptoms in cancer such as pain, fatigue, and despair and even increase the need for sleeping medication and stimulants.

Sleep medicine is linked to many adverse effects

Insomnia is a commonly overlooked problem among cancer patients. Also, some get sleep medicine in the form of benzodiazepines that are known to make you feel sluggish and destroy the highly important REM sleep (Rapid Eye Movement) where dreaming typically occurs. Both sleep medicine and sedatives such as Zolpidem are habit-forming and cause serious side effects and should only be used as last-resort solutions for brief periods of time.
In comparison, melatonin supplements restore the body’s natural sleep pattern – without causing any side effects, whatsoever.

Melatonin has different mechanisms of action

Melatonin is found in all living organisms. In humans, the hormone plays a central role in regulating our 24-hour pattern (the circadian rhythm), which controls many vital processes in the body such as the deep and healthy sleep during nighttime.
Melatonin is even a powerful antioxidant that protects our cells against oxidative stress. At night, melatonin helps repair cellular damage that has occurred in the course of the day. Melatonin is primarily in the small pineal gland (corpus pineale) that is situated in the middle of the brain.

Lack of melatonin and too little sleep are a vicious cycle

The pineal gland decreases in size the older we get. This causes us to produce less melatonin. When we reach our 60s, our melatonin secretion has decreased by around 50% compared with the amount we produce when we were in our 20s. The reduced melatonin secretion is believed to make us age faster and become increasingly susceptible to sleep disturbances and many diseases. Therefore, it easily becomes a vicious cycle when cancer patients and others with chronic disease fail to get their natural sleep at night.

The actual study

50 patients in the ages 20-65 years, all with different forms of cancer, took part in the study. All the patients had suffered from sleep problems for over a month and had not taken sleep medicine in over two weeks. The patients were divided into two groups, group A and group B. Two hours before bedtime, participants in both groups were given either 3 mg of melatonin or dummy pills (placebo) for a two-week period. The study was placebo-controlled and double-blind, which means that neither the patients nor the researchers knew who got what. This was not revealed until after the study had been completed and the researchers were able to access the information.

Before, during, and after the study, the participants were assessed using the Athens Insomnia Scale (AIS), where subjects are supposed to rate the quality of their sleep – including how fast they fall asleep, how many times they wake up during the night, quality of sleep, and sleep duration in total. Also, the participants were asked to answer questions about how they felt the following day in terms of energy levels and fatigue.

Melatonin works fast and has the best effect after 14 days

After the study had been completed, group A (who had been given melatonin) had significantly better sleep quality on several accounts than group B (who got placebo). The sleep improvement reached its maximum after two weeks.
The reason why the scientists let the study run for two weeks was that other scientists had chosen the same length of time for their studies. Also, it appears that it takes more than one week for melatonin to have an optimal effect on the body’s 24-hour rhythm and sleep pattern.
None of the study participants experienced side effects. The researchers refer to earlier studies where supplementation with 3 mg of melatonin had a positive effect on breast cancer patients and others with insomnia. Also, they referred to a study where neither 0.3 mg nor 1 mg of melatonin had an effect, simply because the dosage was too small.

Melatonin inhibits cancer and counteracts the side effects of chemotherapy

Not only is melatonin a sleep hormone. It also possesses several cancer-inhibiting properties that are linked to its function as an antioxidant that protects cells and their DNA. It is documented that melatonin boosts the immune system’s attack on cancer cells and counteracts inflammation and uncontrolled cell proliferation. Melatonin also supports programmed cell death (apoptosis) and controls growth-stimulating hormones like estradiol.
A Danish research article in the journal Ugeskrift for Læger reports that melatonin supplements support chemotherapy in destroying cancer cells and reduces the many side effects. Combining chemotherapy and melatonin increases the chances of surviving cancer from 28.4 to 52.2 per cent over a period of four years.


Madhuri S Kurdi and Sindhu Priya Muthukalai. The Efficacy of Oral Melatonin in Improving Sleep in Cancer Patients with Insomnia: A Randomized Double-Blind Placebo-Controlled Study. Indian Journal of Palliative Care. 2016

Vinter, Anna Gry, Mogens Helweg Claësson: Melatonins indvirkning på immunsystem og cancer. Ugeskrift for Læger 2015

Christensen, Bo Karl: Melatonins effekt på kræft ”næsten for god til at være sand”. 2015

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