Melatonin

Name: Melatonin
Synonym: N-[2-(5-methoxy-1H-indol-3-yl)ethyl] ethanamide
CAS: ：73-31-4
Molecular Formula: C13H16N2O2
Molecular Weight: 232.278
Major Functions:
The use of melatonin as a drug can entrain (synchronize) the circadian clock to environmental cycles and can have beneficial effects for treatment of certain insomnias. Its therapeutic potential may be limited by its short biological half-life, poor bioavailability, and the fact that it has numerous non-specific actions. In recent studies though, prolonged release melatonin has shown good results in treating insomnia.
Products containing melatonin have been available as a dietary supplement in the United States since 1993, and met with good consumer acceptance and enthusiasm. However, over-the-counter sales remain illegal in many other countries including some members of the European Union and New Zealand, and the U.S. Postal Service lists melatonin among items prohibited by Germany.
Studies from Massachusetts Institute of Technology have said that melatonin pills sold as supplements contain three to ten times the amount needed to produce the desirable physiologic nocturnal blood melatonin level for enhancement of sleep. Dosages are designed to raise melatonin levels for several hours to enhance quality of sleep, but some studies suggest that smaller doses (for example 0.3 mg as opposed to 3 mg) are just as effective at improving sleep quality