Research Summary

Analyzed using Evidence Intelligence™

Tirzepatide enhances insulin sensitivity in type 2 diabetes

Key finding

HOMA2-B significantly increased with dulaglutide and tirzepatide 5, 10, and 15 mg compared with placebo (P ≤ .02).

This study compared tirzepatide and dulaglutide in improving insulin sensitivity and beta-cell function in adults with type 2 diabetes, finding tirzepatide more effective.

Evidence strength

Moderate confidence

Study type

RCTs

Follow-up

Medium-Term (3–12 mo)

High bias

Last updated July 5, 2026

Quick read

Study at a glance

The essential study design details in one scan.

Population

Young Adult (19–39), Middle Aged (40-64), Male, Female, Asia-Pacific (APAC), with T2 Diabetes

Intervention

Tirzepatide (1, 5, 10, 15 mg), Dulaglutide (1.5 mg)

Study type

RCTs

Follow-up

Medium-Term (3–12 mo)

Primary outcome

Homeostatic model assessment (HOMA2-B)

Comparator

Placebo

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 compared tirzepatide and dulaglutide in improving insulin sensitivity and beta-cell function in adults with type 2 diabetes, finding tirzepatide more effective.

Clinical relevance

Improving insulin sensitivity and beta-cell function is crucial for managing type 2 diabetes effectively. The findings suggest that tirzepatide may offer a more effective treatment option, potentially leading to better long-term outcomes for patients.

Keep in mind

The study's population may not represent all adults with type 2 diabetes. Long-term effects of tirzepatide were not assessed in this trial. Sample size and duration may limit the generalizability of the findings.

Published in

Journal Reference

Publication details and source links for this paper.

Melissa KT, Amir N, Ross B, et al. Tirzepatide Improves Insulin Sensitivity and Beta-Cell Function Compared to Dulaglutide in Adults with Type 2 Diabetes. The Journal of Clinical Endocrinology and Metabolism. 2021;106(2):388-396. doi:10.1210/clinem/dgaa863

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Main Effects

Tirzepatide 10 and 15 mg significantly decreased fasting insulin levels by 2.5 µU/mL (P ≤ .033).

Proinsulin/insulin ratios significantly decreased with tirzepatide 10 and 15 mg compared to placebo and dulaglutide (P ≤ .007).

HOMA2-B significantly increased with tirzepatide and dulaglutide compared to placebo (P ≤ .02).

Evidence network

How this study fits

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Evidence Context

This study contributes evidence to Dulaglutide, Tirzepatide and Homeostatic model assessment (HOMA2-B), Adiponectin, Fasting insulin levels, and 4 more.

This study contributes evidence to

Intervention

Dulaglutide

Outcome

Homeostatic model assessment (HOMA2-B)

Evidence topic

Insulin Resistance

Primary intervention

Dulaglutide

Primary outcomes

Homeostatic model assessment (HOMA2-B)
Adiponectin
Fasting insulin levels

Evidence topics

Insulin Resistance GLP-1 Receptor Agonists

Primary intervention

Dulaglutide

Primary outcomes

Homeostatic model assessment (HOMA2-B)Adiponectin Fasting insulin levels

Evidence relationships

Intervention and outcome relationships this study adds to the evidence network.

Evidence pairs

Relationships

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: 65

Why it is useful

Contributes to 8 evidence relationships
Includes primary outcome data
Linked to 2 direct semantic evidence topics

Topic contributions

Evidence topic

Contributes evidence

Evidence topic

Tirzepatide → Proinsulin/insulin ratio

Evidence profile

StrongDecreaseMetabolic Health

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Evidence Suggest

Tirzepatide improved insulin sensitivity markers significantly (P < .05).
HOMA2-IR decreased significantly with tirzepatide 10 mg (P = .004).
Dulaglutide also increased HOMA2-B compared to placebo (P ≤ .02).

Who this applies to

Adults diagnosed with type 2 diabetes.
Individuals seeking improved insulin management.

Keep in Mind

Results may not apply to populations outside the study's demographics.
Further studies are needed to confirm long-term benefits of tirzepatide.
The effectiveness of tirzepatide compared to other diabetes treatments remains to be fully explored.

Between the Lines

The study's population may not represent all adults with type 2 diabetes.
Long-term effects of tirzepatide were not assessed in this trial.
Sample size and duration may limit the generalizability of the findings.

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Connected Evidence

Explore related studies, evidence collections, and research questions.

Relationships organized using the Dediabetes Evidence Intelligence™ framework.

This study contributes to evidence on GLP-1 Receptor Agonists and Homeostatic model assessment (HOMA2-B), GLP-1 Receptor Agonists and Adipokine and Angiogenic Markers.

Related evidence relationships

Explore in Evidence Archive

This study contributes to the evidence on the following intervention-outcome relationships.

GLP-1 Receptor AgonistsHomeostatic model assessment (HOMA2-B)

Medications

1 studies

Detailed evidence

GLP-1 Receptor AgonistsAdipokine and Angiogenic Markers

Medications

Does GLP-1 Receptor Agonists improve adipokine and angiogenic markers?

Strong Evidence

GLP-1 Receptor Agonists appears to improve Adipokine and Angiogenic Markers.

ConsensusScore™: Results are consistent across studies.

Ranked evidence signals

1
Adiponectin
EvidenceScore™ Emerging | EvidenceScore™ 59.0 | strong positive | ConsensusScore™ Unclear | 1 study

Why this answer: This answer is based on 7 supporting studies with consistent results and a positive effect signal.

Limitations

Population details are unavailable.

View Full Evidence

Does GLP-1 Receptor Agonists improve insulin resistance?

Strong Evidence

GLP-1 Receptor Agonists may improve Insulin Resistance.

ConsensusScore™: Results are generally consistent across studies.

Ranked evidence signals

1
Fasting insulin levels
EvidenceScore™ Emerging | EvidenceScore™ 59.0 | strong positive | ConsensusScore™ Unclear | 1 study
2
Homeostatic model assessment for insulin resistance (HOMA-IR) change
EvidenceScore™ Emerging | EvidenceScore™ 59.0 | strong positive | ConsensusScore™ Unclear | 1 study

Why this answer: This answer is based on 3 supporting studies with generally consistent results and a positive effect signal.

Limitations

Population details are unavailable.

View Full Evidence

Does Dulaglutide improve homeostatic model assessment (homa2-b)?

Emerging Evidence

Dulaglutide appears to improve Homeostatic model assessment (HOMA2-B).

ConsensusScore™: Consistency cannot yet be determined from the available evidence.

Ranked evidence signals

1
Homeostatic model assessment (HOMA2-B)
EvidenceScore™ Emerging | EvidenceScore™ 59.0 | strong positive | ConsensusScore™ Unclear | 1 study

Why this answer: This answer is based on a single supporting study.

Limitations

Only one supporting study is available.
Consistency cannot yet be determined.
Population details are unavailable.

View Full Evidence

Does Tirzepatide improve homeostatic model assessment (homa2-b)?

Emerging Evidence

Tirzepatide appears to improve Homeostatic model assessment (HOMA2-B).

ConsensusScore™: Consistency cannot yet be determined from the available evidence.

Ranked evidence signals

1
Homeostatic model assessment (HOMA2-B)
EvidenceScore™ Emerging | EvidenceScore™ 59.0 | strong positive | ConsensusScore™ Unclear | 1 study

Why this answer: This answer is based on a single supporting study.

Limitations

Only one supporting study is available.
Consistency cannot yet be determined.
Population details are unavailable.

View Full Evidence

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Next steps

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Evidence topics

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Insulin Resistance Evidence Hub GLP-1 Receptor Agonists Evidence Hub

Explore in archive

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All studies on Dulaglutide and Homeostatic model assessment (HOMA2-B)All studies on Tirzepatide and Fasting insulin levels All studies on Tirzepatide and Homeostatic model assessment (HOMA2-B)All studies on Tirzepatide and Homeostatic model assessment for insulin resistance (HOMA-IR) change

Related research

Read related research summaries.

Tirzepatide improves glycemic control in early-onset type 2 diabetes Switching to tirzepatide from dulaglutide improved HbA1c and weight across baseline characteristics Tirzepatide improves glycemic control and weight loss in type 2 diabetes Tirzepatide improves quality of life in type 2 diabetes patients Dulaglutide may improve weight loss in obese patients with diabetes

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