Melatonin is a mediator which is a precursor of seratonin. It can be found in the epiphysis. Melatonin stimulates the concentration of pigments around the nucleus and the pigment cells of the skin. Its secretion is weak during the day and increases in the dark but the importance of melatonin for the skin pigmentation in mammals is insignificant. Melatonin is an important antioxidant and it helps for the destruction of the free radicals in the organism. This characteristic feature has attributed to its nickname as the 'hormone of youth' since melatonin aids sleep and improves its qualities. As you know it is sleep which helps the organism recover after a tiring day and it is proven that 'good sleep makes for good health'!