Melatonin is a hormone primarily released by the pineal gland at night, and has long been associated with control of 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.