Additionally, this hormone seems to help people handle stress more easily. Stress can cause a breakdown of the immune system which makes us more prone to illness when we are under stress.
Research is also being done to see if it has any effect on cancer cells. But it is too early to tell if this hormone is an effective therapy for cancer.
It has also been shown to be an effective antioxidant against free radicals. In tests, it performed as well or better than other antioxidants.

The best use of this hormone seems to be to regulate sleep. As we age, our melatonin decreases and we find it harder to sleep. (Although my father seems to be able to sleep any time). One study found that the quality of sleep for elderly people was proportionate to the the amount of melatonin in their systems. A study at MIT found that doses as small as .3mg & 1.0mg helped the study group fall asleep faster and increased the quality of their sleep.
Are you having trouble falling asleep? Perhaps taking a supplement would be helpful. Talk to your doctor about it. The amount of this hormone in our bodies is rather small so don't overdo it. Supplements are available in various strengths. They are not regulated by the FDA so taking a synthetic supplement is better than that made from animals.
Side effects usually occur with high doses or in combination with other medications. Taking 1mg or less usually result in no side effects. Doctors recommend that you take the supplements on an empty stomach or with a snack 1-2 hours before bed.
This is just some of the information that I've found about this hormone. If you are interested in learning more, ask your doctor. Most of this information came from Stopping the Clock by Drs.Ronald Klatz and Robert Goldman.