Benzodiazepine Withdrawal – Those who are weaning themselves from Xanax, Valium or Ativan can be helped by melatonin. Insomnia is often a side effect of withdrawing from these drugs, and melatonin can help with those sleep issues. Of course, combining melatonin with those drugs is a no-no unless under a doctor's supervision.

Menopause – There are studies that suggest melatonin helps prevent bone loss in perimenopausal women and may restore quality of life. However, it can’t do anything for hot flashes or some other symptoms. The long-term effects of melatonin on menopause are not yet known.

Breast Cancer – Low melatonin levels may have a connection with a risk of developing breast cancer -- women with the disease have been found to have lower melatonin levels. Lab tests have shown that low melatonin levels seem to stimulate the growth of certain breast cancer cells, while adding melatonin slows their growth. Another added benefit of melatonin is preventing lowered blood platelets, a good thing if undergoing chemotherapy, which often leads to bleeding complications.

Prostate Cancer – Similarly, men with prostate cancer have lower melatonin levels than men who don’t have the disease. Melatonin has been shown to block the growth of prostate cancer cells in lab conditions, but some other tests shows the drug seems to improve survival rates in men with metastatic prostate cancer.

Attention Deficit Hyperactivity Disorder and Autism – Melatonin has been found to be an effective sleep aid for those afflicted with these disorders, although behavioral symptoms remain unchanged.

Fibromyalgia – A significant drop in symptoms for this disease, characterized by aches and pains, has been linked with melatonin levels.