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Melatonin and jet lag symptoms: grade B

Moderate evidence. Direction: Benefit.

B ModerateSubjective outcome onlyShort-term only

Educational guidance, not medical advice

Why this grade

Rubric condition met: >=2 RCTs with mostly consistent results (B); not A because a 257-person trial found no effect

A 2002 Cochrane review found that 9 of 10 placebo-controlled trials in air travelers reported less jet lag when melatonin was taken near the target bedtime after crossing five or more time zones. A trial in 257 physicians after a 6-hour eastward flight found no difference from placebo, and a 2006 meta-analysis that pooled jet lag and shift-work trials found no clear evidence of an effect on sleep onset, a different outcome from jet lag symptoms. Outcomes are mostly self-rated symptoms over a few days, and the main review was published in 2002.

How we grade evidence

Studies this grade rests on

EffectMixedNo effectSize shows participants (n)19952000200520102015Meta-analysisSystematic reviewRCTSpitzer 1999, 1999: RCT, n = 257, result not recordedCostello 2014, 2014: systematic review, n not recorded, result not recordedBuscemi 2006, 2006: meta-analysis, n not recorded, result not recordedHerxheimer 2002, 2002: systematic review, n not recorded, result not recorded
each study this grade rests on, by publication year and design. Solid: effect versus the comparator; half-filled: mixed; hollow: no effect; dashed: result not recorded yet. Larger marks had more participants.
Show the numbers
StudyYearDesignParticipantsResult
Spitzer 19991999RCT257result not recorded
Herxheimer 20022002systematic reviewnot recordedresult not recorded
Buscemi 20062006meta-analysisnot recordedresult not recorded
Costello 20142014systematic reviewnot recordedresult not recorded

The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature.

Costello RB, Lentino CV, Boyd CC. The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature Nutr J, 2014. PMID 25380732

Result not recorded
Design
Rapid evidence assessment (systematic review) of 35 RCTs
Population
Healthy, active adults and people with a history of insomnia
Funding
not stated

Efficacy and safety of exogenous melatonin for secondary sleep disorders and sleep disorders accompanying sleep restriction: meta-analysis.

Buscemi N, Vandermeer B, Hooton N. Efficacy and safety of exogenous melatonin for secondary sleep disorders and sleep disorders accompanying sleep restriction: meta-analysis BMJ, 2006. PMID 16473858

Result not recorded
Design
Systematic review and meta-analysis of RCTs (efficacy) and controlled trials (safety)
Population
People with secondary sleep disorders or sleep disorders accompanying sleep restriction (jet lag, shift work)
Funding
PHS HHS 290-02-0023

Jet lag: clinical features, validation of a new syndrome-specific scale, and lack of response to melatonin in a randomized, double-blind trial.

Spitzer RL, Terman M, Williams JB. Jet lag: clinical features, validation of a new syndrome-specific scale, and lack of response to melatonin in a randomized, double-blind trial Am J Psychiatry, 1999. PMID 10484950

Result not recorded
Design
Randomized, double-blind, placebo-controlled trial (4 arms)
Sample
n = 257
Population
Norwegian physicians after a 6-hour eastward flight
Funding
not stated

Melatonin for the prevention and treatment of jet lag.

Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag Cochrane Database Syst Rev, 2002. PMID 12076414

Result not recorded
Design
Cochrane systematic review of 10 randomized trials
Population
Airline passengers, airline staff and military personnel
Funding
not stated

Search and history

Search (): melatonin[ti] AND "jet lag"[tiab] AND (meta-analysis[pt] OR systematic review[pt] OR cochrane database syst rev[ta])

  • Graded B (proposed): Proposed in the monograph draft
  • B to B (approved): Editor sign-off November 13, 2026: grade matches the editor-approved final page