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The Study

Comprehensive Effects of Melatonin Supplementation on Cardiometabolic Risk Factors: A Systematic Review and Dose–Response Meta-Analysis

In simple terms

This study combines results from 63 different clinical trials to see if melatonin supplements help with heart and metabolism health markers. Because it looks at many experiments together, it gives a good overall picture, but the results vary a lot from study to study, so we can't say it works exactly the same way for everyone.

45%

Analysis score

45/ 100

Maximum 100 for a systematic review with meta-analysis.

Where the score came from

Reporting0
Methodology0
Publication100
Statistical100
Study type (basis of the score)
Systematic Review with Meta-Analysis
Level 1a - Systematic review of RCTs
What’s the bottom line?

This review looked at dozens of studies to see if taking melatonin supplements changes key health markers like blood pressure, sugar, cholesterol, and inflammation.

Where does this study sit?

Reviews of RCTs (Meta-analyses)

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Reviews of RCTs (Meta-analyses)
Level 1a
45

45 / 100

Quality score

The highest quality evidence. Systematic reviews and meta-analyses that pool randomized controlled trials, giving the most reliable summary of experimental evidence.

Can establish causation

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Key takeaways

Summary

Based on the study abstract and findings.

  1. 1While the changes are statistically significant, they are relatively small.
  2. 2The benefits are most noticeable in people with already elevated levels, but melatonin should not replace standard medical treatments for hypertension or diabetes.
  3. 3Melatonin lowered systolic blood pressure by about 2.3 mmHg, fasting blood sugar by 11.6 mg/dL, LDL cholesterol by 6.3 mg/dL, and total cholesterol by 7.0 mg/dL.
  4. 4It also reduced inflammation markers and improved antioxidant levels, but did not change body weight or BMI.

Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data

Publication

Journal

Nutrients

Year

2025

Authors

Shooka Mohammadi, D. Ashtary-Larky, Mahsa Erfanian-Salim, Navid Alaghemand, M. Yousefi, Pouyan Sanjari Pirayvatlou, Mohammadreza Mirkarimi, S. A. Mavi, Ilnaz Alavi, Yeganeh Ettehad, Milad Mehrbod, Omid Asbaghi, Katsuhiko Suzuki, R. Reiter

Open Access
1 citations
Analysis v5

Related Content

Claims (7)

Assertion

Taking melatonin supplements seems to lower fasting blood sugar levels in adults by about 11.6 mg/dL on average. This effect is strongest in people whose blood sugar is already normal or only slightly high, but researchers caution that the current evidence isn't strong enough to rely on melatonin as a main treatment for blood sugar control.

Correlational
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Assertion

Taking melatonin supplements may lower your blood pressure, blood sugar, and bad cholesterol, while also reducing inflammation and boosting your body's natural antioxidants.

Causal
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Assertion

Taking melatonin supplements appears to lower markers of inflammation in the body, such as CRP and IL-6. This reduction in inflammation might help protect the heart, especially for people who already have ongoing, low-level inflammation.

Correlational
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Assertion

Taking melatonin supplements might help improve your cholesterol levels by lowering the 'bad' types and raising the 'good' type. These small changes could potentially benefit your heart health, though it doesn't seem to affect triglycerides.

Correlational
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Assertion

Taking melatonin supplements might slightly lower your top blood pressure number by about 2 points. However, how much it actually helps depends on your starting blood pressure and other personal health factors, so the real-world benefit isn't the same for everyone.

Correlational
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Assertion

Taking melatonin supplements might help your body fight off oxidative stress by lowering harmful markers and boosting natural antioxidants. This improved balance could potentially protect your blood vessels and reduce cell damage linked to metabolic syndrome.

Correlational
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Fit Body Science verdict — we translate health studies into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.