GLP-1 Medications and Type 1 Diabetes: What the Research Shows

GLP-1 receptor agonist medications have transformed the treatment of type 2 diabetes and obesity. They have become some of the most researched drug classes in modern medicine. Naturally, people living with type 1 diabetes (T1D) have asked whether these medications might offer them similar benefits: lower insulin doses, better glucose control, and weight management.

The research is still developing, but the answers so far are nuanced. GLP-1 medications do appear to offer some metabolic advantages as an adjunct to insulin therapy in T1D. At the same time, using them in this context comes with meaningful safety considerations that differ substantially from their use in type 2 diabetes. This article summarizes what the published evidence shows.

*Compounded semaglutide and compounded tirzepatide are not FDA-approved medications. Neither semaglutide nor tirzepatide is currently FDA-approved for use in type 1 diabetes. The information in this article is drawn from published clinical research and is intended for educational purposes only. It does not constitute medical advice. Type 1 diabetes management is highly individualized and requires close collaboration with an endocrinologist or diabetes care specialist. Do not make any changes to your insulin or diabetes medications without consulting your provider.*

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Why Type 1 Diabetes Is Different

Type 1 diabetes is an autoimmune condition. The immune system attacks and destroys the insulin-producing beta cells of the pancreas. People with T1D produce little or no insulin and must replace it exogenously (via injections or an insulin pump) to survive.

GLP-1 receptor agonists work partly by stimulating the pancreas to release insulin in response to glucose. In type 2 diabetes, where residual beta cell function exists, this mechanism is central to their glucose-lowering effect. In type 1 diabetes, where beta cells are largely or entirely absent, this particular pathway is unavailable.

However, GLP-1 receptor agonists affect glucose through several other mechanisms that are relevant in T1D:

• They suppress glucagon, the hormone that tells the liver to release stored glucose. In T1D, inappropriate glucagon secretion is a key driver of high blood sugar.
• They slow gastric emptying, which blunts the rate of post-meal glucose absorption and reduces glucose spikes.
• They reduce appetite and food intake, which supports lower carbohydrate load per meal and modest weight loss in people with T1D who are overweight.

These mechanisms, even without direct beta cell stimulation, give GLP-1 medications a plausible rationale in T1D, particularly as an adjunct therapy on top of insulin.

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The ADJUNCT ONE Trial: The Landmark Liraglutide Study

The most rigorous clinical trial data on GLP-1 use in T1D comes from the ADJUNCT ONE trial, published in Diabetes Care in 2016. This was a randomized, double-blind, placebo-controlled trial that enrolled more than 1,200 adults with T1D and added liraglutide (a GLP-1 receptor agonist in the same drug class as semaglutide) to their existing insulin regimen.

Key findings included: participants on liraglutide 1.8 mg experienced a reduction in HbA1c compared to placebo, a reduction in body weight, and a lower total daily insulin dose. These were meaningful improvements in glycemic management for a population that tends to have relatively few medication options beyond insulin optimization. (Mathieu C et al., Diabetes Care 2016 Oct. PMID: 27506222)

However, the trial also documented a significantly higher rate of symptomatic hypoglycemia in the liraglutide groups. When people reduced insulin doses in response to lower blood glucose levels without careful adjustment, blood sugar could drop too far. This reflects a critical safety point in the T1D context.

A post-hoc analysis of both ADJUNCT ONE and its sister trial (ADJUNCT TWO, which studied lower doses) examined why patients discontinued liraglutide. The primary reasons were gastrointestinal side effects (nausea, vomiting) and hypoglycemia. The analysis also noted that the patients most likely to stay on liraglutide were those with higher BMI and higher baseline HbA1c, suggesting these subgroups may derive more net benefit. (Shah VN et al., J Diabetes Sci Technol 2025 Mar. PMID: 39717993)

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Semaglutide in Type 1 Diabetes: Emerging Evidence

Liraglutide is an older GLP-1 receptor agonist requiring daily injection. Semaglutide (the once-weekly agent) has also been studied in T1D. A 2024 study published in Diabetes Technology and Therapeutics evaluated the efficacy of semaglutide specifically in overweight and obese adults with type 1 diabetes.

The researchers found that semaglutide produced clinically meaningful reductions in body weight and total daily insulin dose in this population. The weight reduction was particularly notable given the well-known challenge of weight management in T1D, where insulin therapy itself can promote weight gain. Improved glycemic control was also observed, though the authors noted the need for careful dose management to avoid hypoglycemia. (Garg SK et al., Diabetes Technol Ther 2024 Mar. PMID: 38444317)

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Tirzepatide in Type 1 Diabetes: 2026 Data

The most recent published evidence involves tirzepatide, the dual GIP/GLP-1 receptor agonist. A June 2026 study in Diabetes Technology and Therapeutics reported on patient-reported adverse events in adults with T1D using adjunctive tirzepatide or semaglutide in real-world clinical practice.

The study found that GI side effects (nausea, vomiting, and constipation) were the most commonly reported adverse events, similar to what is seen in type 2 diabetes. Importantly, the authors documented that patients often reduced their insulin doses as blood glucose improved, which in some cases led to episodes of hypoglycemia or, in a subset, diabetic ketoacidosis (DKA). The authors emphasized that insulin dose adjustment in T1D during GLP-1 initiation must be done under close clinical supervision. (Akturk HK et al., Diabetes Technol Ther 2026 Jun. PMID: 41804758)

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Pediatric Findings: GLP-1 in Youth with Type 1 Diabetes

A 2026 retrospective study examined GLP-1 receptor agonist use in children and adolescents with type 1 diabetes at a single academic center. The researchers found that GLP-1 agents reduced BMI and total daily insulin requirements in this younger population. These findings are particularly relevant given the increasing rates of overweight and obesity in pediatric T1D, a population that faces distinct management challenges. (Gonzalez F et al., J Pediatr Endocrinol Metab 2026 Feb. PMID: 41353583)

The pediatric data, while retrospective and from a single center, suggests that the benefits seen in adult studies may extend to younger patients. Larger prospective trials in pediatric T1D are needed before firm conclusions can be drawn.

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The DKA Risk: What People with T1D Need to Know

The most serious safety concern with GLP-1 use in type 1 diabetes is the risk of diabetic ketoacidosis, including euglycemic DKA (where blood sugar is near-normal but ketone levels are dangerously elevated).

Here is why this happens. GLP-1 medications lower blood glucose through multiple mechanisms. If someone with T1D reduces their insulin dose significantly in response to improved glucose readings, they may inadvertently lower insulin to a level that is insufficient to suppress ketone production, even when blood sugar looks acceptable. The result can be DKA with blood glucose that is not obviously alarming.

This is not theoretical. The ADJUNCT ONE trial documented this, and the 2026 Akturk study reinforced it in the real-world setting. The key clinical message from the T1D research community is that GLP-1 medications should not prompt unguided insulin reduction in T1D. Any adjustments to insulin dosing must be made in close consultation with an endocrinologist and with regular ketone monitoring.

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Who Might Be a Candidate for Future Research or Off-Label Use

Based on available evidence, the people with T1D who appear to derive the most potential benefit from GLP-1 adjunct therapy include:

• Those with overweight or obesity alongside T1D, where weight reduction is an additional goal
• Those with persistently elevated HbA1c despite optimized insulin therapy, particularly if postprandial glucose spikes are contributing
• Those with high insulin requirements who may benefit from the insulin-sparing effect
• Adults rather than children, given that the adult evidence is more robust

It is important to note that GLP-1 medications are not FDA-approved for type 1 diabetes. Their use in this context is off-label and requires a specialist endocrinology team with experience managing T1D, not a general weight loss program.

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What This Means for the Future

Multiple research groups are actively studying GLP-1 receptor agonists in type 1 diabetes. The combination of insulin-sparing effects, weight management, glucagon suppression, and post-meal glucose stabilization gives them a theoretical advantage over simply intensifying insulin alone for people managing both T1D and excess weight.

The field is also exploring whether combining GLP-1 therapy with advanced insulin delivery systems (closed-loop systems or artificial pancreas technology) might mitigate some of the hypoglycemia risks, since automated insulin delivery can respond faster to the glucose-lowering effects of the GLP-1 medication.

For now, the evidence suggests real potential benefits, alongside real risks that require expert management. The research is still catching up to clinical interest.

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A Note on Prescriva

Prescriva supports medically supervised weight management for people living with overweight or obesity. Our compounded GLP-1 program is designed for adults who are not managing type 1 diabetes as their primary indication. If you have T1D and are interested in weight management support, your endocrinologist is the right starting point. They can help determine whether GLP-1 therapy might be appropriate as an adjunct to your insulin management, with the monitoring required to do it safely.

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*This article is for educational and informational purposes only and does not constitute medical advice. Compounded semaglutide and tirzepatide are not FDA-approved products. GLP-1 medications are not FDA-approved for type 1 diabetes. Always consult your licensed healthcare provider and diabetes care specialist before making any changes to your diabetes treatment plan.*

References:

1. Mathieu C et al. Efficacy and Safety of Liraglutide Added to Insulin Treatment in Type 1 Diabetes: The ADJUNCT ONE Treat-To-Target Randomized Trial. Diabetes Care. 2016 Oct. PMID: 27506222
2. Garg SK et al. Efficacy of Semaglutide in Overweight and Obese Patients with Type 1 Diabetes. Diabetes Technol Ther. 2024 Mar. PMID: 38444317
3. Akturk HK et al. Patient-Reported Adverse Events with Adjunctive Tirzepatide or Semaglutide Treatment in Adults with Type 1 Diabetes. Diabetes Technol Ther. 2026 Jun. PMID: 41804758
4. Gonzalez F et al. GLP-1 receptor agonists reduce body mass index and total daily insulin dose in youth with type 1 diabetes: a retrospective study. J Pediatr Endocrinol Metab. 2026 Feb 24. PMID: 41353583
5. Shah VN et al. Determinants of Liraglutide Treatment Discontinuation in Type 1 Diabetes: A Post Hoc Analysis of ADJUNCT ONE and ADJUNCT TWO. J Diabetes Sci Technol. 2025 Mar. PMID: 39717993