•The sleep scenario was artificial and may not totally reflect the effects that would be seen after a long-haul flight. In particular, the efficiency of the drug was tested when the sleep time was brought forwards. As tasimelteon appears to promote the action of melatonin and enhances sleep, it would therefore be of no benefit for travel that causes sleep time to be delayed.
•The studies involved a relatively small number of people and greater numbers would be needed to better clarify the efficiency and, in particular, the safety of the drug. All participants in this study were healthy and different results may have been seen had it been given to those with any medical problems. Those with current sleep disorders were also excluded from the trials, so it cannot be assumed that this drug would be appropriate or safe for use in cases of insomnia unrelated to travel.
•As the researchers note, the studies were not large enough to detect differences in subjective measures, e.g. the individual’s perception of sleep and rest, or any alterations in their alertness or performance.
Importantly, the research did not assess if the ‘improvement’ caused by the drug had an impact on other factors, such as performance. Also the effects of the treatment during waking hours, rather than just effects on sleep is an area that needs further investigation.