Scientists have long been aware of the link between melatonin and a healthy sleep-wake cycle. New evidence reveals previously unknown connections between melatonin and cancer.

Many people use melatonin as a supplement to get better quality sleep and to treat circadian disorders such as jet lag. Several new studies suggest that melatonin also may have an impact in relation to cancer treatment. Not only does it appear to improve response to chemotherapy, but the presence of melatonin may also promote healthy cell growth.

A Possible Link Between Melatonin and Cancer

A study performed in Iceland looked at levels of 6-sulfatoxymelatonin in the urine of men with and without prostate cancer. 6-sulfatoxymelatonin is a metabolite of melatonin, so its presence in urine is a rough indicator of blood melatonin levels. Men with low levels of 6-sulfatoxymelatonin were more likely to report sleep issues such as problems falling or staying asleep. They also were more likely to develop cancer of the prostate gland. In fact, those with higher-than-normal levels of this melatonin metabolite were 75 percent less likely to be diagnosed with advanced prostate cancer.

New Hope for Cancer Treatment?

This study is not the only one pointing to a relationship between low melatonin levels and potential cancer risk. Several other studies have linked higher melatonin levels with lower cancer risk. In addition, melatonin has been found to dramatically improve the effects of chemotherapy.

How can a hormone associated with sleep have such a huge effect when it comes to cancer? Melatonin and cancer appear to be linked, but how? Melatonin is one of the strongest antioxidants produced by the human body. Not only can it promote healthy cell growth, but studies show that patients who take melatonin with their chemotherapy have a higher rate of tumor response and a higher rate of one year survival, even in tumors previously deemed untreatable.

How Melatonin Helps

Recent Discoveries Reveal New Connections Between Melatonin and CancerScientists have identified a few mechanisms behind melatonin's effects. First, it appears to reduce the toxicity of chemotherapy as well as its symptoms, which allows patients to complete their treatments at a higher rate. Melatonin's effects on sleep allow patients to get higher-quality rest, which leaves them physically stronger and healthier. There is also evidence that melatonin also may more directly promote healthy cell growth, but the mechanism of this effect is not currently known. Some researchers believe that melatonin may lower levels of linoleic acid, which increases the growth of some cancers.

Melatonin and Healthy Cell Growth

Doctors and scientists remain unsure about the effects of melatonin in relation to cancer prevention. It is important to talk to your health care provider whenever you add a new supplement or medication to your regimen. However, melatonin has very low toxicity and almost no side effects when taken in a moderate dose, so many health care providers are supportive of its use as a supplement.

While more research will be needed to determine the exact nature of the link between melatonin and cancer, information gathered from studies done to date is very promising. Melatonin appears to be a beneficial adjunct in the treatment of a variety of cancers,  helping patients sleep better and feel healthier during therapies. These new discoveries may change the way doctors approach the treatment of cancer while improving survival and quality of life for people who struggle with disease.