Melatonin mystery.

In the US, where melatonin supplements are available over the counter, millions of adults take them regularly to tackle insomnia, jet lag and night shifts. The British Association for Psychopharmacology, meanwhile, says melatonin may be useful in delayed sleep-wake phase disorder, which includes jet lag, as well as a difficulty falling asleep at the desired time and struggles with waking at the required time, but acknowledges that behavioural regimes can also be used. Kennaway concludes that it is unlikely that the amount of melatonin in so-called melatonin-rich foods will have any physiological impact. In 19 randomised controlled trials, melatonin had a sizeable effect, cutting sleep latency in children by 11 to 51 minutes and boosting sleep duration by 14 to 68 minutes. [Extracted from the article]