With some 1,600 papers to his credit, as well as three honorary doctor of medicine1 degrees, he's published more studies on melatonin than anyone else alive.

Melatonin 101

Melatonin is one of the most important antioxidant molecules and certainly the most ancient, as it has been part of biological life for over 3 billion years. It's present in prokaryotes, which are bacteria, and even in plants. In the human body — aside from having direct antioxidant effects — it also stimulates the synthesis of glutathione and other important antioxidants like superoxide dismutase and catalase. Reiter continues:

"Melatonin has been here forever … and its functions have evolved. It has learned to work successfully with other molecules during this three-billion-year evolution. One of the molecules with which it collaborates is glutathione … But the antioxidant activity of melatonin is extremely diverse.

It in fact is a very good radical scavenger. There are other radical scavengers — vitamin C, vitamin E and so forth — but melatonin is superior to those. But beyond that, it stimulates antioxidative enzymes, especially in mitochondria. Mitochondria are small organelles in the cell that generate the bulk of the free radicals.