Melatonin (N-acetyl-5-methoxytryptamine) is a compound secreted mainly by the pineal gland, but synthesized also in many other tissues and cells. In humans, nocturnally peaking oscillations of melatonin are involved in sleep-wakefulness where melatonin concentrations are lower during the day. In recent years, the role of melatonin and its metabolites have been identified as potent, broad acting antioxidants and free radical scavengers in addition to playing a role in the upregulation of antioxidant enzymes. Melatonin levels in plasma are paralleled by corresponding variations in saliva where the saliva concentrations are about 30% of that found in plasma. Measurement of salivary melatonin is advantageous, especially to avoid invasive venipuncture procedures. http://www.creative-diagnostics.com/Melatonin-Salivary-ELISA-Kit-188206-465.htm