WN-Acetylserotonin (NAS), also known as normelatonin, is a naturally occurring chemical precursor and intermediate in the endogenous production of melatonin from serotonin. It also has biological activity in its own right, including acting as a melatonin receptor agonist, an agonist of the TrkB, and having antioxidant effects.
WAgomelatine is an atypical antidepressant used to treat major depressive disorder. One review found that it is as effective as other antidepressants with similar discontinuation rates overall but less discontinuations due to side effects. Another review also found it was similarly effective to many other antidepressants.
WGR-196,429 is a melatonin receptor agonist with some selectivity for the MT1 subtype. It was one of the first synthetic melatonin agonists developed and continues to be used in scientific research, though it has never been developed for medical use. Studies in mice have shown GR-196,429 to produce both sleep-promoting effects and alterations of circadian rhythm, as well as stimulating melatonin release.
W6-Hydroxymelatonin (6-OHM) is a naturally occurring, endogenous, major active metabolite of melatonin. Similar to melatonin, 6-OHM is a full agonist of the MT1 and MT2 receptors. It is also an antioxidant and neuroprotective, and is even more potent in this regard relative to melatonin.
WMelatonin is a hormone primarily released by the pineal gland that regulates the sleep–wake cycle. As a dietary supplement, it is often used for the short-term treatment of insomnia, such as from jet lag or shift work, and is typically taken by mouth. Evidence of its benefit for this use, however, is not strong. A 2017 review found that sleep onset occurred six minutes faster with use, but found no change in total time asleep. The melatonin receptor agonist medication ramelteon may work as well as melatonin supplements, at greater cost but with different adverse effects, for some sleep conditions.
WMelatonin receptor agonists are analogues of melatonin that bind to and activate the melatonin receptor. Agonists of the melatonin receptor have a number of therapeutic applications including treatment of sleep disorders and depression. The discovery and development of melatonin receptor agonists was motivated by the need for more potent analogues than melatonin, with better pharmacokinetics and longer half-life. Melatonin receptor agonists were developed with the melatonin structure as a model.
WPiromelatine (Neu-P11) is a multimodal sleep drug under development by Neurim Pharmaceuticals. It is an agonist at melatonin MT1/MT2 and serotonin 5-HT1A/5-HT1D receptors. Neurim is conducting a phase II randomized, placebo controlled trial of cognitive and sleep effects in Alzheimer's disease.
WRamelteon, sold under the brand name Rozerem among others, is a sleep agent medication that selectively binds to the MT1 and MT2 receptors in the suprachiasmatic nucleus (SCN), instead of binding to GABAA receptors, such as with drugs like zolpidem.
WTasimelteon is a drug approved by the U.S. Food and Drug Administration (FDA) in January 2014 for the treatment of non-24-hour sleep–wake disorder. In June 2014, the European Medicines Agency accepted an EU filing application for tasimelteon and in July 2015, the drug was approved in Europe for the treatment of non-24-hour sleep-wake rhythm disorder in totally blind adults, but not in the rarer case of non-24 in sighted people.
WTIK-301 (LY-156735) is an agonist for the melatonin receptors MT1 and MT2 that is under development for the treatment of insomnia and other sleep disorders. Its agonist action on MT1 and MT2 receptors in the suprachiasmatic nucleus in the brain enables its action as a chronobiotic. It is in the same class of melatonin receptor agonists as ramelteon and tasimelteon.