The test group with large doses could be a melatonin hangover, leaving the user drowsy during the day. Solid evidence shows that melatonin help those who zip across time zones. Lewy's experiment shows the body's adjustment time can be cut in half. Melatonin can also help people with erratic work shifts. Melatonin's backers claim the hormone is an antioxidant like Vitamins C and E and, like them, may help fight cancer.
Antioxidants help the body scoop up free radicals before they cause harm.
In studies by biologist Russel J. Reiter of the University of Texas at San Antonio, melatonin was a potential scavenger of free radicals. In an experiment a group was given melatonin, another group received none. Then both were given safrole, which causes cancer. Melatonin is reported to have very few side effects. The substance is quickly cleared from the body via the liver, and Reiter insists you can't give an animal enough natural melatonin to kill it.