Poor sleep can affect daytime performance
A new cure for jet lag could be on the market in the next few years after trials show a pill can reset the body's natural sleep rhythms.
Tasimelteon works by shifting the natural ebb and flow of the body's sleep hormone melatonin.
In trials, published in The Lancet, the drug helped troubled sleepers nod off quicker and stay asleep for longer.
Experts said the drug would be a welcome alternative to addictive sedatives like benzodiazepines.
Commenting on the work, Dr Daniel Cardinali from the University of Buenos Aires said the findings would be welcomed by millions of people - "shift-workers, airline crew, tourists, football teams, and many others."
Body clock trickery
The hope is that if you have shifted your body clock and you've slept well, then you should perform well the next day, said lead researcher Dr Elizabeth Klerman at Brigham and Women's hospital in Boston.
In trials on 450 people who went to bed five hours earlier than normal to replicate crossing into a different time zone, those who took the drug enjoyed between 30 minutes and nearly two hours more sleep than volunteers who received a dummy pill.
TOP TIPS FOR AVOIDING JET LAG
Top up on sleep before you travel
Shift your watch to your destination time zone as soon as you board the plane
Spend plenty of time outdoors in the daylight
Natural melatonin - the darkness hormone which peaks at night - is a popular treatment for patients with body clock-related sleep disorders.
But the researchers say the potency, purity, and safety of melatonin pills is largely unregulated. Also, there are mixed results about whether they work in shift-workers and people with jet lag.
The US team says more work is now needed to check that their drug, which works on the same receptors in the body as melatonin, actually improves daytime performance and alertness without any carryover sedative effect.