HormonesMelatonin

Higher plasma melatonin levels are associated with slightly greater objective sleep efficiency but not with subjective sleep quality in adults aged 25-65 years.

In a cross-sectional study of 334 adults (mean age 43 years), plasma melatonin levels showed no significant association with Pittsburgh Sleep Quality Index scores, but higher melatonin levels were linked to slightly greater sleep efficiency measured by actigraphy. Mean plasma melatonin concentration was 14.5 ± 15.9 pg/mL, with higher levels in men and a decreasing trend with age.

Last updated: Aug 6, 2026•0 RCTs•📖 Read as article →

Evidence Score

Evidence Score9/100
Human RCT☆☆☆☆☆
Meta-analysis☆☆☆☆☆
Mechanism★★★★★
Safety★★☆☆☆
Confidencelow

Study Evidence

Study 1. Plasma Melatonin Levels, Seasonal Variation, and Sleep Quality: A Stratified Analysis of Adults Aged 25-65 Years Using the Pittsburgh Sleep Quality Index and Actigraphy.

observational

Garcia-Yu IA, Crespo-Sedano A, Jiménez-Vaquero C, Gonzalez-Sanchez J, Alonso-Dominguez R, Sanchez-Aguadero N, Recio-Rodriguez JI · International journal of molecular sciences (2026)

Participants: N/A
Duration: Cross-sectional (5-day actigraphy protocol)
Intervention: Plasma melatonin levels (endogenous, measured by HPLC-DAD-MS/MS)
Outcome: Sleep quality (Pittsburgh Sleep Quality Index score) and objective sleep efficiency (5-day wrist actigraphy)
Effect Size: N/A (no specific effect size reported in abstract)
Population: Adults aged 25-65 years from Salamanca and Ávila, Spain

Result:

PubMed: 42511663DOI: 10.3390/ijms27146320

Mechanism Graph

Melatonin is a hormone regulating circadian rhythms
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Higher melatonin levels may promote sleep onset and maintenance
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Objective sleep efficiency (actigraphy) captures actual sleep continuity
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Subjective sleep quality (PSQI) is influenced by multiple factors beyond melatonin

Limitations

  • ⚠Cross-sectional design prevents causal inference
  • ⚠Seasonal variation in melatonin levels was not statistically significant, limiting interpretation
  • ⚠Only 334 of 500 participants had valid melatonin measurements, potential selection bias

Frequently Asked Questions

Does higher melatonin improve sleep quality in adults?▼

This study found no association between plasma melatonin levels and subjective sleep quality (PSQI), but higher levels were linked to slightly better objective sleep efficiency measured by actigraphy.

What was the average melatonin level in this study?▼

The mean plasma melatonin concentration was 14.5 ± 15.9 pg/mL, with higher levels in men and a decreasing trend with age.

Did melatonin supplements help sleep in this study?▼

Participants reporting melatonin supplement use had higher PSQI scores (worse subjective sleep) and lower total sleep time compared to non-users, suggesting no benefit.

Was there a seasonal effect on melatonin levels?▼

A trend toward higher melatonin levels during winter was observed, but the differences were not statistically significant.

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References

  1. 1.Garcia-Yu IA, Crespo-Sedano A, Jiménez-Vaquero C, Gonzalez-Sanchez J, Alonso-Dominguez R, Sanchez-Aguadero N, Recio-Rodriguez JI. "Plasma Melatonin Levels, Seasonal Variation, and Sleep Quality: A Stratified Analysis of Adults Aged 25-65 Years Using the Pittsburgh Sleep Quality Index and Actigraphy.." International journal of molecular sciences, 2026. PMID: 42511663 DOI: 10.3390/ijms27146320
Disclaimer: This content is for educational purposes only and is not medical advice. Evidence scores reflect the quality and quantity of available research, not clinical recommendations. Always consult a healthcare professional before starting any supplement or intervention.