Researchers report that news in yesterday's online edition of The Lancet.
Melatonin, made by the pineal gland, helps set the body's sleep-wake schedule. Tasimelteon is a melatonin-like drug that's in development. Another melatonin-like drug, called Rozerem, is already approved by the FDA to treat insomnia.
Those experiments compared various doses of tasimelteon to a placebo in healthy adults who didn't have chronic sleep problems and who were regularly getting eight hours of nightly sleep.
During the experiments, participants' sleep schedule was suddenly advanced by five hours, such as sleeping from 6 p.m. to 2 a.m. after being used to sleeping from 11 p.m. to 7 a.m.
People who got tasimelteon slept longer and reported better sleep than people who got the placebo, report the researchers, who included Harvard Medical School's Shantha Rajaratnam, PhD.
Side effects, which were similar in the tasimelteon and placebo groups, were generally mild and included headache, according to the study, which was funded by tasimelteon's maker, Vanda Pharmaceuticals of Rockville, Md.
Further studies should be done to see how tasimelteon affects people during the day, Rajaratnam and colleagues note.
An editorial published with the study points out that melatonin-like drugs don't make people sleepy like other types of sleeping pills do, and consumers would need to be educated about that so their expectations are reasonable.