Melanoma and Melatonin
Effect of Melatonin on Melanoma
There is a wide range of evidence that high doses of melatonin can help prevent melanoma, and also can help kill melanoma tumors and help stop them from spreading. See below for a partial listing of studies, some on animals and some on people, supporting the use of melatonin in fighting melanoma. You can also search PubMed.gov for "melanoma melatonin".
It has also been shown that the amount of melatonin taken affects its effectiveness. It is not known what the "ideal" amount to be taken should be, however, many doctors who use melatonin for melanoma treatment will suggest something in the range of 20mg per night. It is best to take it at night because it causes drowsiness.
Research Evidence on Melatonin
(1) On the Role of Melatonin in Skin Physiology and Pathology A. Slominski,1 T. W. Fischer,1,2 M. A. Zmijewski,1 J. Wortsman,3 I. Semak,4 B. Zbytek,1,5 R. M. Slominski,1 and D. J. Tobin6. Endocrine. 2005 July; 27(2): 137–148.
(2) Melatonin therapy of advanced human malignant melanoma. Gonzalez R, Sanchez A, Ferguson JA, Balmer C, Daniel C, Cohn A, Robinson WA. Melanoma Res. 1991 Nov-Dec;1(4):237-43. Division of Medical Oncology, University of Colorado Cancer Center, Denver 80262.
(3) Direct antiproliferative effects of melatonin on two metastatic cell sublines of mouse melanoma (B16BL6 and PG19). Cos, S.*; Garcia-Bolado, A.; Sánchez-Barceló, E. J. Melanoma Research: April 2001 - Volume 11 - Issue 2 - pp 197-201
(4) Melatonin decreases cell proliferation and induces melanogenesis in human melanoma SK-MEL-1 cells. Javier Cabrera1,2, Gledy Negrín2,3, Francisco Estévez2,3, Juan Loro1,2, Russel J. Reiter4, José Quintana2,3. Journal of Pineal Research, Volume 49, Issue 1, pages 45–54, August 2010
(5) MT-1 melatonin receptor expression increases the antiproliferative effect of melatonin on S-91 murine melanoma cells. Kadekaro AL, Andrade LN, Floeter-Winter LM, Rollag MD, Virador V, Vieira W, Castrucci AM. J Pineal Res. 2004 Apr;36(3):204-11.
(6) CANCER RESEARCH 45,4175-4177, September 1985. Effect of Melatonin on B16 Melanoma Growth in Athymic Mice Takeo Marita1and Hajime Kudo. Second Department of Pathology, Hirosaki University School of Medicine, Hirosaki, 036 Japan
Side Effects and Warnings
A safety study found that melatonin at a dose of 10 mg daily produced no toxic effects when given to 40 healthy males for a period of 28 days. ^ However, this does not prove that melatonin is safe when taken on a regular basis over the long term. Keep in mind that melatonin is not truly a food supplement but a hormone. As we know from other hormones used in medicine, such as estrogen and cortisone, harmful effects can take years to appear. Hormones are powerful substances that have many subtle effects in the body, and we're far from understanding them fully. While in one small study, use of melatonin over an 8-day period by healthy men did not affect natural release of melatonin or levels of pituitary or sex hormones, ^ another study found effects on testosterone and estrogen metabolism in men and possible impairment of sperm function. ^ Also, a small study in women found possible effects on the important female hormone called LH (luteinizing hormone). ^ Melatonin appears to cause drowsiness and decreased mental attention for about 2 to 6 hours after using it and may also impair balance. ^ For this reason, you should not drive or operate machinery for several hours after taking melatonin. In a study of healthy middle-aged and older adults, however, an extended release version of melatonin, which is said to more closely mimic natural fluctuations of the hormone in the body, did not impair mental ability or driving skills 1 to 4 hours later compared to placebo. ^ In either case, melatonin does not appear to have any "hangover" effects the following day. ^ Based on theoretical ideas of how melatonin works, some authorities specifically recommend against using it in people with depression, schizophrenia, autoimmune diseases, and other serious illnesses. One study in postmenopausal women found evidence that melatonin might impair insulin action and glucose tolerance, suggesting that people with diabetes should not use it. ^ However, another study found melatonin safe and effective for people with diabetes. ^ Because of these contradictions, we suggest that individuals with diabetes seek physician supervision before using melatonin.
Two exceedingly preliminary studies reported by one research group has led to publicized concerns that use of the supplement melatonin might increase night-time asthma. ^ However, one double-blind study of melatonin in people with asthma found evidence of improved sleep without worsening of symptoms. ^ Again, at the current state of knowledge, caution must be advised for people with night-time asthma who wish to try melatonin.
There is some evidence that melatonin may interfere with the ability of blood to clot normally, at least in healthy volunteers, ^ though the clinical significance of this finding is at yet unknown.
Maximum safe dosages for young children, pregnant or nursing women, or those with serious liver or kidney disease have not been established.