An experimental drug that mimics the effects of the hormone melatonin can reset body rhythms, and maybe bring relief to jet-lagged travelers and night-shift workers, according to a study in The Lancet. Researchers at Brigham and Women’s Hospital found the drug restored almost normal sleep on the first night it was used in a group of 450 people who were subjected to simulated jet lag in a sleep lab.

There were no aftereffects from the drug, minimal side effects, and people who took it performed normally the next day, Elizabeth Klerman, one of the co-authors, tells The Los Angeles Times. The drug, which is called tasimelteon, has no potential for addiction or abuse, she adds. UPDATE: A loyal reader opens our eyes by reminding us that tasimelteon has the same mechanism of action as ramelteon, which is better known as Rozerem and is the first melatonin analogue approved for treating insomnia.

However, the study, which was designed and funded by Vanda Pharmaceuticals, which developed the drug, involved a rather small group of patients and researchers were unable to measure performance and mood after the drug was used. All of the researchers, the Times notes, reported receiving funds from Vanda or other drugmakers.

“This is a very promising first step,” Jay Udani, who runs the integrative medicine program at Northridge Hospital Medical Center and who was not involved in the study, tells the paper. But the research “does not prove that it works for jet lag or shift workers. That needs controlled studies in the field.”

In the first part of the study, normal sleep habits in 39 patients were monitored for three nights in the lab before being sent to bed five hours early, the Times writes, adding they were given one of four different doses of tasimelteon or a placebo 30 minutes before bedtime. Sleep efficiency - percentage of time in bed actually slept - was monitored, as was the amount of time required to fall asleep.

Although all the subjects benefited from the drug, those receiving the highest dose had a sleep efficiency of 89 percent the first night, virtually the same as the 90 percent efficiency before the trail started. Those receiving a placebo had an efficiency of 71 percent, the Times writes.

Patients taking the highest doses slept for an average of about 428 minutes, compared with 430 minutes before the trial and 324 minutes for those taking a placebo, the paper continues. It took an average of seven minutes for them to go to sleep, compared with 11 minutes before the trial and 22 minutes for those receiving a placebo.