There is no clear cut evidence that melatonin has the same sleep-inducing effect in the night. The study was conducted by researchers at Brigham and Women's Hospital and Harvard Medical School. This study was published in the current issue of the journal Sleep. It had 36 volunteers each was housed in a soundproof room with dim lighting, no windows and no hint of real time.
The study extended for a period of four-weeks and the volunteers were kept on strict 20-hour cycles of sleep and wakefulness. This was done mainly to break the body's 24-hour clock. The study's lead author, James Wyatt, says that this would mimic the off-hour sleep-wake cycle that shift workers and jet-lagged travelers often struggle with. In the night the participants were given either melatonin or a placebo.
It was found that those who received melatonin slept longer than the placebo group in the day. During the night when melatonin is already being released by the brain supplements did not seem to have an effect than that of a placebo group. In conclusion he said that melatonin works differently than the prescription drugs and hence is of no great help for those who suffer from insomnia. Melatonin is safe for adults for a short period of time with few side effects.