How Does Tirzepatide Compare to Other GLP-1 Drugs When Added to Insulin? | Research

The takeaway

Tirzepatide at all doses produced significantly greater reductions in HbA1c and body weight than GLP-1 receptor agonists when used with basal insulin.

All 3 doses superior
Tirzepatide 5, 10, and 15 mg all showed statistically significant greater HbA1c and weight reductions vs. all GLP-1 RA comparators

What the researchers found

Tirzepatide at all doses (5, 10, 15 mg) significantly outperformed GLP-1 RAs for both blood sugar control and weight loss when combined with basal insulin.

Why it matters

Many type 2 diabetes patients need add-on therapy to insulin. This analysis suggests tirzepatide may offer superior benefits over existing GLP-1 drugs in this population.

The numbers in context

- 6 randomized controlled trials included in the network meta-analysis

- Tirzepatide at all 3 doses (5, 10, 15 mg) showed significantly greater HbA1c reduction vs all GLP-1 comparators

- Tirzepatide at all 3 doses showed significantly greater weight reduction vs all GLP-1 comparators

- No significant differences in treatment discontinuation rates vs GLP-1 comparators (except tirzepatide 10/15 mg vs placebo)

How the study worked

Network meta-analysis of 6 randomized controlled trials comparing tirzepatide with GLP-1 RAs in patients on basal insulin.

Who was studied

Adults with type 2 diabetes on basal insulin, drawn from 6 randomized controlled trials comparing tirzepatide to GLP-1 receptor agonists.

What this study cannot tell us

Indirect comparison via network meta-analysis, not head-to-head trials. Limited number of studies (6). Relatively short follow-up at primary endpoints.

How to read the evidence

Network meta-analysis of RCTs provides moderate-to-high quality evidence, though indirect comparisons carry more uncertainty than head-to-head trials.

When this study was published

Published in 2025 based on existing RCT data.

The bigger picture

As dual GIP/GLP-1 receptor agonists like tirzepatide emerge, they may become preferred add-on therapies for insulin-treated patients needing better glycemic and weight control.

Questions still open

Would tirzepatide maintain superiority in longer-term studies?
How does tirzepatide compare to semaglutide specifically in this population?

Common questions

Is tirzepatide better than GLP-1 drugs for people on insulin?

This analysis found tirzepatide at all tested doses produced greater reductions in blood sugar and body weight compared to dulaglutide, exenatide, and lixisenatide when added to basal insulin.

Does tirzepatide cause more side effects?

Tirzepatide caused more nausea than placebo and exenatide, but side effect rates were similar to other GLP-1 drugs overall.

Read the original research

Efficacy and Safety of Tirzepatide Compared with GLP-1 RAs in Patients with Type 2 Diabetes Treated with Basal Insulin: A Network Meta-analysis.

Diabetes therapy : research, treatment and education of diabetes and related disorders, 16(6), 1279-1311

View on PubMed ↗Publisher’s paper ↗

Citation

Osumili, Beatrice; Sapin, Hélène; Yang, Zhengyu; Ranta, Kari; Paik, Jim S; Blüher, Matthias. (2025). Efficacy and Safety of Tirzepatide Compared with GLP-1 RAs in Patients with Type 2 Diabetes Treated with Basal Insulin: A Network Meta-analysis.. Diabetes therapy : research, treatment and education of diabetes and related disorders, 16(6), 1279-1311. https://doi.org/10.1007/s13300-025-01728-5