GLP-1 Drugs for Type 1 Diabetes: Do They Help With Weight and Insulin Doses? | Research

The takeaway

A large meta-analysis of 24 trials found that adding GLP-1 drugs (especially liraglutide) to insulin therapy in type 1 diabetes reduces weight and insulin needs, but significantly increases nausea.

-2.2 kg weight loss per mg of liraglutide
Across 24 trials and 3,377 type 1 diabetes patients, liraglutide produced dose-dependent weight loss along with reduced insulin needs — but nausea risk increased 6.5-fold.

What the researchers found

This meta-analysis of 24 randomized controlled trials (3,377 patients) found that GLP-1 analogs — particularly liraglutide — provide meaningful benefits when added to insulin therapy in type 1 diabetes. Liraglutide produced dose-dependent reductions in A1c (-0.09% per mg), body weight (-2.2 kg per mg), and total daily insulin (-4.32 IU per mg).

However, higher liraglutide doses came with significantly increased nausea (OR 6.5) and modestly elevated ketosis risk (OR 1.8). Importantly, GLP-1 therapy did not significantly increase severe or symptomatic hypoglycemia. Patients who were newly diagnosed or still producing some insulin (C-peptide positive) showed greater A1c reductions (-0.51% vs -0.28%) but similar weight loss.

Why it matters

Type 1 diabetes patients increasingly struggle with obesity, yet they have very few approved add-on therapies beyond insulin. This comprehensive meta-analysis provides the strongest evidence to date that GLP-1 analogs — drugs primarily developed for type 2 diabetes — can meaningfully help type 1 patients lose weight and reduce their insulin doses, though the trade-off includes significant nausea and a small increase in ketosis risk.

The numbers in context

24 RCTs · 3,377 patients · 4 GLP-1 analogs · A1c: -0.09%/mg liraglutide · Weight: -2.2 kg/mg · TDI: -4.32 IU/mg · Nausea OR 6.5 · Ketosis OR 1.8

How the study worked

Systematic review and meta-analysis of randomized controlled trials from PubMed, EMBASE, Cochrane Central, and Scopus through December 2022. Included 24 studies testing 4 different GLP-1 analogs in type 1 diabetes patients for at least 12 weeks. Assessed efficacy (A1c, weight, insulin dose) and 12 adverse outcomes. Used GRADE framework for evidence certainty.

Who was studied

Patients with type 1 diabetes, including subgroups of newly diagnosed and C-peptide positive patients

What this study cannot tell us

Most evidence comes from liraglutide studies, so findings for other GLP-1 analogs (exenatide, etc.) are less robust. Studies of exenatide had higher risk of bias and sparse safety data. No GLP-1 analog is currently FDA-approved for type 1 diabetes, so all use remains off-label. The meta-analysis could not assess very long-term outcomes beyond typical trial durations.

How to read the evidence

This is a systematic review and meta-analysis of 24 randomized controlled trials — the highest level of evidence synthesis. It used GRADE methodology and included a large pooled sample of over 3,300 patients, with subgroup analyses for key populations.

When this study was published

Published in 2023 with literature search through December 2022. This is current and represents the most up-to-date meta-analysis on GLP-1 use in type 1 diabetes.

The bigger picture

GLP-1 drugs have transformed type 2 diabetes and obesity treatment, but their role in type 1 diabetes remains off-label and uncertain. This meta-analysis builds the strongest case yet for their use as add-on therapy, particularly for the growing number of type 1 patients dealing with overweight and obesity. The findings could inform future regulatory decisions about formally approving these drugs for type 1 diabetes.

Questions still open

Should GLP-1 analogs be formally studied for FDA approval as adjunctive therapy in type 1 diabetes?
Can the ketosis risk be managed safely in type 1 patients, or does it represent a barrier to wider use?
Would newer, more potent GLP-1 drugs like semaglutide show even greater benefits in this population?

Common questions

Can people with type 1 diabetes take GLP-1 drugs like Ozempic or Wegovy?

GLP-1 drugs are not FDA-approved for type 1 diabetes, but this meta-analysis of 24 trials shows they can help with weight loss and reducing insulin doses when used off-label. Liraglutide had the most evidence. However, nausea is very common and there's a small increased risk of ketosis.

Do GLP-1 drugs lower blood sugar in type 1 diabetes?

Modestly. The A1c reduction was about 0.09% per mg of liraglutide — helpful but not dramatic. The bigger benefits were weight loss and reduced insulin requirements. Patients who still produced some of their own insulin (C-peptide positive) saw larger A1c drops.

Read the original research

Glucagon-Like Peptide 1 Analogues as Adjunctive Therapy for Patients With Type 1 Diabetes: An Updated Systematic Review and Meta-analysis.

The Journal of clinical endocrinology and metabolism, 109(1), 279-292

View on PubMed ↗Publisher’s paper ↗

Citation

Park, Jeayoung; Ntelis, Spyridon; Yunasan, Elvina; Downton, Katherine D; Yip, Terry Cheuk-Fung; Munir, Kashif M; Haq, Nowreen. (2023). Glucagon-Like Peptide 1 Analogues as Adjunctive Therapy for Patients With Type 1 Diabetes: An Updated Systematic Review and Meta-analysis.. The Journal of clinical endocrinology and metabolism, 109(1), 279-292. https://doi.org/10.1210/clinem/dgad471