Melatonin
Melatonin is a hormone produced in the pineal gland, a small gland in the brain. Melatonin is involved in regulating circadian rhythms, the regular daily cycles of the body such as sleeping and waking. Blood levels of melatonin are high at night and low during the day.
Many therapeutic benefits have been claimed for melatonin. Most studies have evaluated its effects on sleeping problems. For insomnia, some, but not all, clinical investigations have shown a therapeutic effect with melatonin. Studies of another sleep disorder, jet lag, have produced mixed results. No studies strongly support the use of melatonin treatment for cancer.
A possible role of melatonin in causing MS has been proposed. In one study, high blood levels of melatonin were associated with a later age of onset of the disease and a shorter duration of the disease. The significance of these findings in relation to melatonin causing MS or the effect of taking melatonin supplements on MS is not known
People with MS should be aware that melatonin may activate the immune system. The effects of melatonin on the immune system are not fully understood. However, specific immune cells called T cells have sites to which melatonin attaches, and some studies have shown that melatonin stimulates T cells. Melatonin has been proposed as a possible treatment for AIDS and cancer on the basis of its immune-stimulating effects. Also, melatonin treatment worsens a mouse model of another autoimmune disease, arthritis.
In summary, melatonin may be helpful for insomnia and jet lag. However, it has a theoretical risk for people with MS because it may stimulate the immune system. It would be reasonable for people with MS to avoid melatonin. If melatonin is used by people with MS, high doses and long-term use should probably be avoided.