Melatonin is primarily produced by the pineal gland (glandula pinealis). This organ has been mentioned as early as Galen of Pergamon and other Greeks in the second century. In the 16th century, the French philosopher and scientist, Descartes, described the pineal gland as the seat of the soul.
Melatonin itself was only first discovered in 1958 by a dermatologist named Aaron Lerner, and it has been researched extensively since the 1980s. Lerner was able to isolate a compound in a bovine pineal gland that had a strong bleaching effect on amphibian skin, which he gave the name melatonin. It was also Lerner who began studying the effect of the hormone on sleep. After a self-experiment with 100 mg of melatonin, Lerner reported that he had no side effects except for drowsiness. In the 1960s it was still assumed that the light-dark rhythm was important for mammals, but not for humans. Not until 1981 did Alfred Lewy discover that bright light applied in the night suppressed endogenous melatonin in humans. This discovery was a breakthrough for chronobiology and research of melatonin. In the beginning of the 1990s, the hormone received more and more attention as studies showed the effects of melatonin on different bodily processes such as immune modulation, restraining tumor growth, catching of oxygen radicals and the influence on calcium dependent metabolic processes. Subsequently, additional studies are available about melatonin and its multifaceted impact on human health.