Semaglutide produced 13.3% weight loss, reduced insulin needs by 14%, and dramatically improved fatty liver markers in 42 overweight adults with type 1 diabetes over 12 months.
13.3% weight lossMean weight loss in overweight/obese type 1 diabetes patients treated with once-weekly semaglutide for 12 months — comparable to results in type 2 diabetes trials
What the researchers found
In 42 overweight/obese adults with type 1 diabetes, once-weekly semaglutide produced a mean relative weight loss of 13.3% over 12 months — comparable to results seen in type 2 diabetes and obesity trials. Glycemic control also improved, and the proportion of patients with significant liver stiffness (>8 kPa, suggesting liver scarring) dropped dramatically from 20.6% to just 4.5%.
Total daily insulin requirements decreased by 13.6%, suggesting that semaglutide reduces insulin resistance even in the type 1 diabetes setting where insulin production is absent. Eight of 42 patients (19%) discontinued treatment, mainly due to gastrointestinal intolerance. The study provides the first substantial real-world evidence that semaglutide is safe and effective in type 1 diabetes, a population for which it is not currently approved.
Why it matters
Semaglutide is not approved for type 1 diabetes, and there are very few clinical studies in this population. Yet obesity is increasingly common among T1D patients, contributing to insulin resistance and fatty liver disease. This real-world study suggests semaglutide could benefit T1D patients in the same ways it helps T2D patients — weight loss, better glucose control, and liver improvement — potentially opening the door to formal clinical trials and eventual approval.
The numbers in context
n=42 · 76.2% with obesity · 13.3% mean weight loss · 13.6% insulin dose reduction · Liver stiffness >8 kPa: 20.6% → 4.5% · 12-month follow-up · 19% discontinuation rate
How the study worked
Real-world observational study of 42 overweight/obese adults with type 1 diabetes treated with once-weekly semaglutide for 12 months. Inclusion required stable glycemic control at baseline. Outcomes included weight change, HbA1c, total daily insulin dose, and liver stiffness measured by FibroScan (in 28 patients). Published in Diabetes Technology & Therapeutics.
Who was studied
Overweight/obese adults with type 1 diabetes (mean age 46, mean BMI 32.2, mean diabetes duration 28 years)
What this study cannot tell us
Small sample size (n=42) without a control group — the real-world design means there's no placebo comparison. The 19% discontinuation rate suggests tolerability issues in a subset of patients. Liver stiffness was only measured in 28 of 42 patients. Without randomization, selection bias may have favored patients more likely to respond well. Off-label use may not reflect how the drug would perform in a broader T1D population.
How to read the evidence
This is a real-world observational study without a control group, which limits causal conclusions. However, it is one of the first studies of meaningful size to evaluate semaglutide in type 1 diabetes, published in a respected diabetes technology journal. The consistent improvements across multiple outcomes add credibility.
When this study was published
Published in 2025. Represents some of the first real-world evidence for semaglutide in type 1 diabetes, a rapidly evolving area of clinical interest.
The bigger picture
Type 1 diabetes has traditionally been treated exclusively with insulin, but the rising obesity epidemic means many T1D patients now face the same metabolic complications as T2D patients — insulin resistance, fatty liver, and cardiovascular risk. This study is part of a growing body of evidence suggesting GLP-1 agonists can help T1D patients with these metabolic issues, even though the drugs don't address the autoimmune cause of their diabetes.
Questions still open
- Will pharmaceutical companies pursue formal clinical trials of semaglutide in type 1 diabetes based on this and similar real-world evidence?
- Is the liver improvement from semaglutide in T1D driven primarily by weight loss, or does the drug have direct hepatoprotective effects?
- How should GLP-1 drugs be dosed in T1D patients who are already on insulin, given the 14% insulin reduction observed?
Common questions
Can people with type 1 diabetes take semaglutide?
Did semaglutide help with fatty liver in type 1 diabetes patients?
Read the original research
Real-World Evidence of the Effect of Adjunctive Semaglutide on Weight Change, Glycemic Control, and Metabolic Dysfunction-Associated Steatotic Liver Disease in People with Type 1 Diabetes.
Diabetes technology & therapeutics
Citation
Mertens, Jonathan; De Winter, Hennah T; Dirinck, Eveline; Francque, Sven; De Block, Christophe. (2025). Real-World Evidence of the Effect of Adjunctive Semaglutide on Weight Change, Glycemic Control, and Metabolic Dysfunction-Associated Steatotic Liver Disease in People with Type 1 Diabetes.. Diabetes technology & therapeutics. https://doi.org/10.1177/15209156251362497