Melatonin for Jet Lag
Verdict: Disputed
Across 6 PubMed studies, the evidence for Melatonin in Jet Lag grades Tier B — preliminary evidence. High-quality studies disagree — the evidence is genuinely mixed.
B 🟡 B Preliminary Evidence Disputed
Why this grade7-layer evidence engine
⚖️
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.73
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
B · Disputed
Confidence
82%
Highly consistent evidence
Evidence level
E1
Cochrane high-quality SR/MA
▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.73
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (3 篇 > 0 negative)
- tier_strict_requirement_check — | A→B 因 L4 有 ≥1 against
- detect_disputes — 偵測到 1 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status
PubMed studies (6)L2 · primary research & systematic reviews
Melatonin for the prevention and treatment of jet lag
Finding: Nine of ten included RCTs found that melatonin (0.5-5 mg taken at destination bedtime) reduced jet lag after crossing 5+ time zones, with a number-needed-to-treat of 2.
View on PubMed Efficacy of Functional Foods, Beverages, and Supplements Claiming to Alleviate Air Travel Symptoms: Systematic Review and Meta-Analysis
Finding: Random-effects meta-analysis found melatonin significantly reduced self-reported jet lag eastbound (5 trials, SMD -0.76, 95% CI -1.06 to -0.45, p<0.00001) and westbound (4 trials, SMD -0.66, 95% CI -1.07 to -0.26, p=0.001), though authors cautioned the underlying evidence base was limited.
View on PubMed Jet lag: clinical features, validation of a new syndrome-specific scale, and lack of response to melatonin in a randomized, double-blind trial
Finding: In the largest double-blind RCT (257 Norwegian physicians, 5 mg / 0.5 mg / shifting 0.5 mg vs placebo), there were no significant group differences or group-by-time interactions and no group effect on sleep onset, awakening, or hours slept.
View on PubMed Comparative study to determine the optimal melatonin dosage form for the alleviation of jet lag
Finding: Of 320 randomized (234 analyzed), the 5 mg fast-release melatonin formulation significantly improved self-rated sleep quality, shortened sleep latency, and reduced fatigue and daytime sleepiness (all p<0.05), while 2 mg controlled-release was not effective.
View on PubMed Unraveling the Impact of Travel on Circadian Rhythm and Crafting Optimal Management Approaches: A Systematic Review
Finding: PRISMA-2020 systematic review of 23 high-quality studies (2020-2024) concluded melatonin supplementation, alongside personalized light exposure and chrono-modulation, can significantly improve sleep quality and reduce jet-lag symptoms, but reported only qualitative findings with no pooled effect size.
View on PubMed Melatonin for jet lag
Finding: This Drug and Therapeutics Bulletin evidence review concluded that immediate-release melatonin taken at destination bedtime can reduce jet-lag symptoms after crossing several time zones, echoing the Cochrane NNT of 2, while noting evidence quality and product-quality limitations; no new pooled effect size was generated.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Cautious
no basis to conclude that melatonin is GRAS source↗
L4b EU EFSA
Supportive
melatonin and reduction of sleep onset latency source↗
L4c UK NHS
Cautious
Melatonin is available on prescription only. source↗
L4d TW TFDA / 衛福部
Against
褪黑激素產品屬藥品列管 source↗
L4e WHO
Not addressed
altered melatonin excretion source↗
L5a NIH Office of Dietary Supplements
Cautious
short-term use of melatonin supplements appears to be safe source↗
L5b Mayo Clinic
Supportive
Evidence shows that melatonin can improve jet lag symptoms, such as alertness and daytime sleepiness. Taking a relatively low dose of melatonin (0.5 milligrams) — one of the strengths available over the counter — also has been shown to be effective. source↗
L5c Cleveland Clinic
Supportive
If you experience any of these disorders, or if you've got jet lag, melatonin can be a good supplement to get you back on track. source↗
L5d Harvard Health
Cautious
Some small studies have suggested that melatonin is helpful for jet lag if taken a few days before and after travel. Melatonin has been more effective at treating eastward jet lag, and so might be more helpful to you on the outbound trip—when taken close to the target bedtime. source↗
L5e Specialty Society (condition-mapped)
Supportive
Melatonin administered at the appropriate time is indicated to reduce symptoms of jet lag and improve sleep following travel across multiple time zones. source↗