Abstract
Objective: To describe the main characteristics the action of melatonina on the human. Bibliographic Review: Currently, research has been going to discover more and more about actions of melatonina (MEL) in humans. The literature describes as the sleep hormone, fundamental in the circadian rhythm of the human. Several physiological actions MEL occur through its interaction with membrane receptors, called: MT1 and MT2. In addition, it plays important role during the life cycle. They reach the highest values in sérum levels in child development and prepuberal phase. It under goesa progressive decrease in puberty, decreasing significantly with aging. Currently, studies report that MEL has been chowing antioxidante, anti-inflammatory, anthioncostatic action and also in the elimination of free radicals. It also has na otoprotective action, na importante action on the placenta during pregnancy and still acts on the female genital system. Final considerations: Is concluded, that melatonina has a fundamental role in the circadian rhythm of the human as well as in treatment with protective actions in the body, and can be used in research so that there is a greater scientific advance through its applicability in several áreas of health that may be applied in the future in increasingly specific treatment.