Evidence Intelligence™
- EvidenceScore™
- Moderate
- Score 69 · Based on 2 studies
- ImpactScore™
- 50
- Neutral
- ConsistencyScore™
- 100
- consistent
Supporting studies: Based on 2 studies
Add to Evidence TrackerResearch Summary
Analyzed using Evidence Intelligence™
Melatonin shows little effect on glycemic control in type 2 diabetes
Last updated August 16, 2026
Key finding
FBG levels in the placebo arm decreased significantly at the end of trial.
This study investigated the effect of melatonin on glycemic control in patients with type 2 diabetes, finding no significant differences between melatonin and placebo groups.
Quick read
Study at a glance
The essential study design details in one scan.
EvidenceScore™
Moderate
Study type
RCTs
Follow-up
Short-Term (≤3 mo)
Risk of bias
Some Concerns
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Plain-language summary
What this paper says
A plain-language read of the study’s main message and where it applies.
Study focus
This study investigated the effect of melatonin on glycemic control in patients with type 2 diabetes, finding no significant differences between melatonin and placebo groups.
Clinical relevance
Understanding the effectiveness of melatonin for glycemic control is crucial for managing type 2 diabetes. This study suggests that melatonin may not be a beneficial treatment option for improving blood sugar levels, guiding clinicians in their treatment choices.
Keep in mind
The study may have limited generalizability due to specific inclusion criteria. Sample size and duration may not have been sufficient to detect subtle effects. Unmeasured confounders could have influenced the outcomes.
Published in
Journal Reference
Publication details and source links for this paper.
Amir F, Maryam T, Noushin SA, et al. The Effect of Melatonin on Glycemic Control in Patients with Type 2 Diabetes: A Triple-Blind, Placebo-Controlled Trial. Iranian Journal of Pharmaceutical Research : IJPR. 2019;18(Suppl1):258-268. doi:10.22037/ijpr.2019.112011.13485
Main Effects
No significant changes in fasting blood glucose levels between melatonin and placebo groups (p=0.897).
No significant changes in HbA1c levels between groups (p=0.912).
FBG levels in the placebo group decreased significantly at the end of the trial.
Evidence network
How this study fits
Understand where this research contributes within the broader evidence network.
Evidence Context
This study contributes evidence to Melatonin and C-reactive protein, Fasting blood sugar (FBS), HbA1c, and 2 more.
This study contributes evidence to
Primary intervention
Melatonin
Primary outcomes
- C-reactive protein
- Fasting blood sugar (FBS)
- HbA1c
Primary intervention
Primary outcomes
Evidence relationships
Intervention and outcome relationships this study adds to the evidence network.
5
Evidence pairs
5
Relationships
3
Evidence topics
contributes_evidence
Editorial context
Why this study matters
See why this paper is useful beyond its individual results.
Evidence network role
This section describes how the study fits into the current evidence network. It does not determine whether an intervention works on its own.
Moderate contributionModerate confidenceNetwork score: 68
3
Related topics
5
Evidence pairs
681
Related studies
High relevance in at least one topic
Why it is useful
- Contributes to 5 evidence relationships
- Includes primary outcome data
- Linked to 3 direct semantic evidence topics
Topic contributions
Evidence topic
Contributes evidence
Evidence topic
Contributes evidence
Evidence topic
Contributes evidence
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Primary evidence
Evidence topic
Glycemic Control
matched_outcome
Related evidence
Evidence topic
HbA1c Reduction
Save evidence
Core evidence
Study findings
The primary outcomes reported in this study.
Evidence Intelligence™
- EvidenceScore™
- Emerging
- Score 59 · Based on 1 study
- ImpactScore™
- 50
- Neutral
- ConsistencyScore™
- unclear
- Not enough independent studies
Supporting studies: Based on 1 study
Add to Evidence TrackerEvidence Intelligence™
- EvidenceScore™
- 77
- Strong
- ImpactScore™
- 67
- Slightly Positive
- ConsistencyScore™
- 67
- generally_consistent
Supporting studies: Based on 3 studies
Add to Evidence TrackerEvidence Intelligence™
- EvidenceScore™
- Moderate
- Score 69 · Based on 2 studies
- ImpactScore™
- 50
- Neutral
- ConsistencyScore™
- 100
- consistent
Supporting studies: Based on 2 studies
Add to Evidence TrackerEvidence Intelligence™
- EvidenceScore™
- Moderate
- Score 69 · Based on 2 studies
- ImpactScore™
- 38
- Slightly Negative
- ConsistencyScore™
- 35
- mixed
Supporting studies: Based on 2 studies
Add to Evidence TrackerEvidence Library
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Evidence Suggest
- No significant difference in fasting blood glucose between melatonin and placebo (p=0.897).
- HbA1c levels showed no significant change between groups (p=0.912).
- Placebo group experienced a significant decrease in fasting blood glucose levels.
Who this applies to
- Adults diagnosed with type 2 diabetes.
- Participants who were not on melatonin prior to the study.
Keep in Mind
- Results may not apply to all populations with diabetes.
- The study did not assess long-term effects of melatonin.
- Further research is needed to explore potential benefits in different contexts.
Between the Lines
- The study may have limited generalizability due to specific inclusion criteria.
- Sample size and duration may not have been sufficient to detect subtle effects.
- Unmeasured confounders could have influenced the outcomes.
Evidence Library
Build your evidence library
Save research, organize studies, and quickly find important evidence again.
Connected Evidence
Explore related studies, evidence collections, and research questions.
Relationships organized using the Dediabetes Evidence Intelligence™ framework.
This study contributes to evidence on Melatonin and HbA1c, Melatonin and Inflammatory Markers.
Related evidence relationships
Explore in Evidence ExplorerThis study contributes to the evidence on the following intervention-outcome relationships.
Supplements
Melatonin → HbA1c
Supplements
Evidence Intelligence™
- EvidenceScore™
- 77
- Strong
- ImpactScore™
- 67
- Slightly Positive
- ConsistencyScore™
- 67
- generally_consistent
Supporting studies: Based on 3 studies
View evidenceSupplements
Melatonin → Inflammatory Markers
Supplements
Evidence Intelligence™
- EvidenceScore™
- Moderate
- Score 69 · Based on 2 studies
- ImpactScore™
- 50
- Neutral
- ConsistencyScore™
- 100
- consistent
Supporting studies: Based on 2 studies
View evidenceIncluded in these evidence collections
Curated evidence collections and hubs this study is part of.
HbA1c Evidence Hub
All studies measuring HbA1c
3 studies
outcome_hubMeasures HbA1c as a key outcome.
Melatonin Evidence Hub
All studies on Melatonin
3 studies
intervention_hubContributes to Melatonin evidence base.
Inflammatory Markers Evidence Hub
All studies measuring Inflammatory Markers
2 studies
outcome_hubMeasures Inflammatory Markers as a key outcome.
Explore more in Evidence Explorer
Jump to pre-filtered views in Evidence Explorer.
All studies on Melatonin and HbA1c
Intervention: MelatoninOutcome: HbA1c
3 results
All studies on Melatonin and C-reactive protein
Intervention: MelatoninOutcome: C-reactive protein
2 results
All studies on Melatonin
Intervention: Melatonin
3 results
All studies measuring HbA1c
Outcome: HbA1c
3 results
All studies measuring C-reactive protein
Outcome: C-reactive protein
2 results
Questions answered by this study
Generated from the study's connected evidence using Evidence Intelligence™.
Does Melatonin improve HbA1c?
Strong Evidence
Melatonin may improve HbA1c.
ConsistencyScore™: Results are generally consistent across studies.
Ranked evidence signals
- 1
HbA1c
EvidenceScore™ Strong | EvidenceScore™ 77.4 | weak positive | ConsistencyScore™ Generally Consistent | 1 study
Why this answer: This answer is based on a single supporting study.
Limitations
- Only one supporting study is available.
- Population details are unavailable.
Does Melatonin improve c-reactive protein?
Moderate Evidence
Current evidence does not show a clear benefit of Melatonin for C-reactive protein.
ConsistencyScore™: Results are consistent across studies.
Ranked evidence signals
- 1
C-reactive protein
EvidenceScore™ Moderate | EvidenceScore™ 69.0 | neutral | ConsistencyScore™ Consistent | 1 study
Why this answer: This answer is based on a single supporting study.
Limitations
- Only one supporting study is available.
- Population details are unavailable.
Does Melatonin improve insulin resistance?
Moderate Evidence
Current evidence does not show a clear benefit of Melatonin for Insulin resistance.
ConsistencyScore™: Results are consistent across studies.
Ranked evidence signals
- 1
Insulin resistance
EvidenceScore™ Moderate | EvidenceScore™ 69.0 | neutral | ConsistencyScore™ Consistent | 1 study
Why this answer: This answer is based on a single supporting study.
Limitations
- Only one supporting study is available.
- Population details are unavailable.
Does Melatonin improve insulin sensitivity?
Moderate Evidence
Melatonin may worsen Insulin sensitivity or be associated with harm.
ConsistencyScore™: Results are mixed and should be interpreted cautiously.
Evidence caveat: The available evidence reports mixed findings.
Ranked evidence signals
- 1
Insulin sensitivity
EvidenceScore™ Moderate | EvidenceScore™ 69.0 | weak negative | ConsistencyScore™ Mixed | 1 study
Why this answer: This answer is cautious because the available studies report mixed findings.
Limitations
- Only one supporting study is available.
- Population details are unavailable.
Next steps
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