Melatonin is a hormone most people associate with sleep, but it also has powerful effects on the immune system which can then have a flow on action to hormonal conditions involving the immune system, such as endometriosis.
Receptors, which are like docking sites for hormones, have been found for melatonin, on the endometrium, and also on endometriomas and peritoneal lesions.
In animal studies, consumption of a melatonin supplement was found to decrease endometriotic lesion volume. These results were mirrored in one small randomised controlled trial, where supplementation with melatonin (at a relatively high dose of 10mg) for 8 weeks considerably reduced pain (by approx 40%) in women suffering from endometriosis. This subsequently led to reduced need for pain killers in women with endometriosis compared to the comparison group.
Melatonin appears to work in multiple ways; it reduces angiogenesis (new blood vessel growth which typically feeds endometrial lesions), it inhibits oestradiol-induced cell growth thus assisting to prevent an immune response that allows the ectopic endometrial implants to invade into the peritoneum, & it also appears to be pain relieving.
While the research is limited at this stage, Melatonin combined with other therapies offers a novel, less invasive option compared to hysterectomy, for women with endometriosis to try.