Type 1 Diabetes, Weight Struggles and Tirzepatide
If you’re living with Type 1 diabetes, you’re already a professional problem-solver. You count, calculate, plan ahead, recover when things go sideways, and still show up at work, for your family, and for your life.
But if you also live with extra weight, insulin resistance, fatigue, stubborn highs, or huge insulin doses, you’ve probably wondered:
“Is there anything besides ‘more insulin’?”
“Why am I gaining weight doing exactly what I’ve been told?”
You’re not lazy. You’re not broken. You’re dealing with a metabolic system that’s complicated—and for many adults with T1D, also insulin resistant.
Recently, researchers looked at a medication you’ve probably heard about in the context of type 2 and weight loss: tirzepatide—a dual GIP/GLP-1 agonist—used off-label in adults with Type 1 diabetes. And the results are interesting enough that, as your “think-with-me” physician, I want you to actually understand them.
Quick Refresher: What is Tirzepatide (Mounjaro)?
Tirzepatide activates both GLP-1 and GIP receptors—hormone pathways that:
Help your body respond to glucose more effectively
Improve satiety (you feel full sooner)
Slow gastric emptying
Support weight loss
It’s FDA-approved for Type 2 diabetes and obesity, not for Type 1 diabetes. Using it in T1D is currently off-label and should only be considered with a knowledgeable clinician who understands both the data and the risks.
The Study in Plain English
A 2024 proof-of-concept observational study followed 26 adults with Type 1 diabetes who were prescribed tirzepatide in addition to insulin. These were not “easy” patients: average age 42, average BMI 36.7 (in the obesity range), most using pumps and CGMs.
What happened over 8 months?
A1c: Dropped by about 0.45% at 3 months and ~0.59% by 8 months.
Weight: Decreased by about 3.4% at 3 months, and around 10% by 6–8 months—and stayed there.
Time in Range (70–180 mg/dL): Increased by about 12%, sustained over time.
Time Below Range: Did not significantly increase.
Insulin Needs: Total daily insulin dose dropped by roughly 20–25%.
Safety: In this small group:
No diabetic ketoacidosis (DKA) reported.
Two patients stopped due to side effects (severe hypoglycemia in one, severe constipation in one).
One case of possible nerve palsy associated with rapid weight loss. PMC
In short: for adults with T1D and obesity, tirzepatide improved weight, A1c, time in range, and insulin needs in this real-world setting—without an obvious spike in severe lows or DKA in that sample.
Before You Get Too Excited: The Fine Print
This is where your inner researcher will (and should) kick in.
This study:
Was small (26 people)
Was retrospective (looking back at records)
Had no control group
Had non-standardized dosing
Was done at a single center
All of that means: it’s a signal, not a final answer. We now have additional emerging data and ongoing trials looking at GLP-1s and tirzepatide as adjunctive therapy in T1D, but we are still in the “promising, not definitive” phase. PMC+2PMC+2
Most importantly:
Tirzepatide is not FDA-approved for Type 1 diabetes.
Any use in T1D is off-label and should be:
Individualized
Closely monitored
Paired with careful insulin adjustments and education on hypoglycemia and DKA risk
Who Might This Be Relevant For?
This conversation might be worth having if you are an adult with T1D who:
Has obesity or significant weight gain despite doing “everything right”
Is on high daily insulin doses
Struggles with post-meal spikes, insulin resistance, or wide swings
Is motivated, data-driven, and willing to track CGM metrics, ketones when needed, and symptoms closely
This is not a cosmetic “I want a quick 10-pound loss” tool for T1D.
This is about metabolic burden, cardiovascular risk, insulin resistance, quality of life—and whether an adjunct tool can safely help.
How I Approach This as Your Doctor
In a Direct Primary Care model, I’m not trying to rush you through a 7-minute visit or throw trendy meds at you.
If we are exploring something like tirzepatide in Type 1 diabetes, we’re going to:
Map Your Baseline Clearly
A1c, CGM data, time in range
Total daily insulin (basal vs bolus)
Weight, BMI, cardiovascular + kidney risk factors
History of DKA, severe lows, gastroparesis, pancreatitis, etc.
Talk Honestly About Off-Label Use
What the evidence shows so far (and doesn’t)
Risks: hypoglycemia, GI side effects, cost, access
DKA risk if insulin is reduced too aggressively
If Appropriate, Start Low & Monitor Hard
Gradual dose titration
Intentional insulin adjustments (not guesswork)
Close monitoring of CGM, ketones when indicated, and symptoms
Ongoing reevaluation: Is this helping your glucose, weight, quality of life, or not?
Integrate, Not Outsource
Nutrition, movement, sleep, stress, hormone balance still matter.
Tirzepatide is a tool, not your new identity.
Your Takeaways
You’re not imagining it: obesity and insulin resistance are common in T1D and make management harder.
Tirzepatide and other incretin-based therapies are being studied as adjuncts in this exact group—and early signals are promising.
We are not at the “everyone with T1D should be on this” stage.
If you’re curious whether this could fit your situation, that curiosity is valid—and you deserve a thoughtful, science-based discussion, not a brush-off.
Soft Call to Action
If this struck a chord—if you’re a Type 1 who’s tired of feeling like the only answer is “add 10 more units”—
👉Schedule an interest call with me at Arbor Internal Medicine.
We’ll sit down (not rush), review your data, your story, and your risk profile, and decide together whether exploring options like tirzepatide makes sense for you—or if there’s a better next step.
And if you have a T1D friend who is always reading the studies and feels unheard, forward this to them. They’re my people, too.
— Dr. Danielle Ivey
Arbor Internal Medicine, PA
Reference:
Akturk HK, Dong F, Snell-Bergeon JK, Karakus KE, Shah VN. Efficacy and Safety of Tirzepatide in Adults With Type 1 Diabetes: A Proof of Concept Observational Study. J Diabetes Sci Technol. 2025 Mar;19(2):292-296. doi: 10.1177/19322968231223991. Epub 2024 Feb 5. PMID: 38317405; PMCID: PMC11571402.
