Since jet lag is a self-limiting short-term problem and there is limited published evidence of the benefit of melatonin on symptoms, the DTB authors argue the hormone should be blacklisted for this condition.
Licensed melatonin 3mg tablets and 1mg/ml oral solution were launched last year.
Evidence of melatonin's efficacy largely comes from small studies in which the source and form of melatonin were not always reported, say the DTB reviewers. Most of these trials were published between 1986 and 2005.
A 2015 meta-analysis of data from four studies in a total of 232 people showed a modest effect on symptoms, with jet lag severity (assessed using a 100-point scale) rated at 27 by people taking melatonin and 45 by those given placebo.
Drowsiness and sleepiness, headache, dizziness and disorientation are the most frequently reported adverse effects of melatonin.
NICE's Clinical Knowledge Summary on jet lag does not recommend melatonin as a treatment.
The DTB points out that GPs are not required to prescribe medicines for the treatment of a condition that is not present and may arise while a patient is abroad. A private prescription may therefore be appropriate for those travelling from the UK who wish to take melatonin for the treatment of jet lag.
Sustained-release melatonin preparations are licensed to treat insomnia in adults from 55 years and in children with autism.