Tirzepatide in Type 1 Diabetes: Does It Reduce Daily Insulin Needs? | Research

The takeaway

Study evaluating tirzepatide as add-on therapy in type 1 diabetes assessed its effect on total daily insulin dose, exploring whether GLP-1/GIP agonism can reduce insulin requirements in T1D.

Less insulin needed?
Tirzepatide evaluated as insulin-sparing add-on therapy in T1D — potentially reducing daily insulin dose while improving weight and control

What the researchers found

Study assessed tirzepatide's ability to reduce total daily insulin dose in T1D adults, exploring GLP-1/GIP agonism as insulin-sparing therapy.

Why it matters

T1D patients take insulin for life but face constant challenges with weight gain and hypoglycemia. If tirzepatide can reduce insulin needs, it addresses both problems simultaneously.

The numbers in context

Not detailed in available abstract — study focused on total daily insulin dose changes and glycemic control measures.

How the study worked

Clinical evaluation of tirzepatide as add-on to insulin therapy in adults with T1D. Assessed changes in total daily insulin dose, HbA1c, weight, and safety.

Who was studied

Type 1 diabetes patients on insulin plus metformin and/or GLP-1/GIP receptor agonists

What this study cannot tell us

T1D patients always need some insulin. GLP-1/GIP drugs do not replace insulin in T1D. Risk of DKA if insulin is reduced too aggressively. Not FDA-approved for T1D.

How to read the evidence

Moderate evidence: clinical evaluation of tirzepatide in T1D for insulin dose reduction.

When this study was published

Published in 2025. Explores an off-label but increasingly researched application.

The bigger picture

GLP-1 drugs were originally avoided in T1D, but growing evidence shows they can be safe and beneficial as add-on therapy. Tirzepatide's dual GLP-1/GIP mechanism may offer additional benefits for T1D patients beyond what single GLP-1 drugs provide.

Questions still open

How much can tirzepatide safely reduce insulin doses in T1D?
Does reduced insulin dose translate to fewer hypoglycemic episodes?
Should tirzepatide be pursued for FDA approval in T1D?

Common questions

Can T1D patients use tirzepatide?

It's being studied but not yet approved for T1D. Some endocrinologists prescribe it off-label alongside insulin. It may reduce insulin needs and help with weight management, but T1D patients must never stop insulin entirely.

How would tirzepatide help in type 1 diabetes?

By improving insulin sensitivity and promoting weight loss, tirzepatide may allow T1D patients to use less insulin. Less insulin means fewer hypoglycemic episodes and less insulin-related weight gain — two major T1D challenges.

Read the original research

Evaluating the Effect on Total Daily Insulin Dose in Adult Patients with Type 1 Diabetes Managed with Metformin and/or GLP-1 or GLP-1/GIP Receptor Agonists.

Innovations in pharmacy, 16(1)

View on PubMed ↗Publisher’s paper ↗

Citation

Ahmed, Mayeesha; Pierson, Emily; Webster, Molly. (2025). Evaluating the Effect on Total Daily Insulin Dose in Adult Patients with Type 1 Diabetes Managed with Metformin and/or GLP-1 or GLP-1/GIP Receptor Agonists.. Innovations in pharmacy, 16(1). https://doi.org/10.24926/iip.v16i1.6450