March 2, 2005 - As dietary supplements go, melatonin was a superstar just a decade ago. Books and newsmagazines celebrated the hormone as a cure for sleep ills, aging, and even cancer. But the scientific evidence to back up the hype never materialized.
These days, the supplement is largely promoted as a natural way to get a good night's sleep. But does it work?
A large review of studies, published late last year, found melatonin to be safe when taken for short periods but not particularly effective for people with long-term sleep problems. Now a newly published review of selected research shows the hormone to be modestly effective in treating insomnia.
Sleep medicine specialist Frank Scheer, PhD, of Boston's Brigham and Women's Hospital has studied melatonin for several years. He says the jury is still out on the supplement's effectiveness for promoting nighttime sleep in people with long-term sleep problems.
Are Benefits Overstated?
I think it is fair to conclude that melatonin is not the miracle sleep aid that it was once believed to be," he tells WebMD. "Its benefits for sleep have been largely overstated."
In a review of 130 studies, published in December 2004, researchers reported that taking melatonin appears at best to be mildly beneficial in the treatment of insomnia and other ongoing sleep disorders. The report also found little evidence of a benefit for jet lag.
But the review did indicate that people with a specific sleep condition known as sleep phase syndrome can benefit from taking the hormone for limited periods. People with this condition have a hard time both falling asleep at night and waking in the morning.
The newly published report included 17 studies involving 284 people with and without insomnia. The studies varied in things such as the amount and quality of the melatonin taken by the participants.
Researchers concluded that taking melatonin reduced the time it took people to fall asleep by an average of 4 minutes. Total sleep time per night was increased by about 13 minutes.
"The general conclusion was drawn that melatonin has only a modest sleep-promoting effect, with an increase in sleep efficiency of 2% to 3%," Scheer wrote in an editorial accompanying the analysis. Both were published in the February issue of the journal Sleep Medicine Reviews.