Could Meds for Type 2 Diabetes Also Help Those with Type 1? A Look at Using Type 2 Medications in a Type 1 World.
By Paula Diab, PhD, CDCES
Exploring new horizons in diabetes care
Recently, Gary Scheiner and I had a discussion on our “Think Like a Pancreas: The Podcast” about this topic. Here is a brief overview of the discussion, or you can go to your favourite platform for listening to podcasts and get the full episode.
When most people think about type 1 diabetes (T1D), they think of insulin — and for good reason.
Insulin is absolutely essential for people living with T1D, and nothing can replace it. But in recent years, researchers have been asking an interesting question: what if some of the medications used in type 2 diabetes (T2D) could also help people with type 1?
This idea may sound unusual at first, but it actually makes a lot of sense. Let’s unpack why.
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Why Look at Type 2 Medications in Type 1?
Type 1 diabetes is an autoimmune condition where the body no longer makes insulin. Type 2 diabetes, on the other hand, is usually linked with insulin resistance — where the body still makes insulin, but the cells don’t respond to it properly.
Traditionally, these have been treated very differently:
- Type 1 = insulin therapy
- Type 2 = lifestyle changes, tablets, and sometimes insulin
But here’s the catch: many people with T1D also develop insulin resistance. This can happen for lots of reasons — weight gain, family history, or just the natural effects of living with diabetes over time. Doctors sometimes call this situation “double diabetes.”
When insulin resistance is added on top of type 1 diabetes, managing blood sugars can become more challenging:
- Higher insulin doses are often needed
- Weight gain may become a problem
- Glucose control may remain frustrating, even with diligent insulin use
And that’s where type 2 diabetes medications come in. Some of them specifically target insulin resistance, appetite, or weight — things insulin alone doesn’t fix.
Metformin: The Old Classic
Metformin is one of the oldest and most widely used medications for type 2 diabetes. It works by reducing the amount of glucose released by the liver and improving insulin sensitivity.
The REMOVAL Trial
The largest study of metformin in type 1 diabetes was called the REMOVAL trial. Over 400 adults with long-standing T1D took either metformin or placebo for three years.
What it found:
- No long-term improvement in HbA1c
- Small, sustained weight loss (<1 pound)
- Modest reduction in insulin dose
- Lower LDL cholesterol
- Signs of slowing in blood vessel thickening (a marker of heart disease risk)
Metformin probably isn’t a game-changer for blood sugar control in T1D. But it may have benefits for weight, cholesterol, and long-term heart health. For some people, that makes it a useful add-on.
SGLT2 Inhibitors: The “Kidney Helpers”
A newer class of drugs, SGLT2 inhibitors, works by helping the kidneys pass excess glucose out in the urine. This lowers blood sugar without relying on insulin. They also cause weight loss and reduce blood pressure.
The two biggest programs testing these in T1D are the DEPICT trials (dapagliflozin) and the EASE trials (empagliflozin). Both trials showed a modest reduction in HbA1c levels (~0.3-0.5%) as well as lower insulin dose usage and a fair amount of weight loss (1-2 pounds). The dapaglifozin trial (DEPICT) showed better time in range (TIR), but there did seem to be a higher risk of diabetic ketoacidosis (DKA). The very low 2.5 mg dose of empaglifozin seemed to improve glucose and weight without increasing DKA risk compared with placebo.
SGLT2 inhibitors may improve blood sugars, weight, and insulin needs in T1D. But the risk of DKA means they must be used very cautiously, and they’re only approved for very specific patients in some countries.
GLP-1 Receptor Agonists: The “Satiety Signals”
Another exciting group of medications is the GLP-1 receptor agonists (like liraglutide and semaglutide). These drugs mimic a natural gut hormone that:
- Slows stomach emptying
- Increases feelings of fullness
- Reduces appetite
- Lowers glucagon (another hormone that raises blood sugar)
In type 2 diabetes, GLP-1 drugs are well known for lowering HbA1c and helping with weight loss. But what about type 1?
Liraglutide Trials
- ADJUNCT ONE and TWO: Showed weight loss, lower insulin needs, and some HbA1c improvement — but not dramatic. Side effects (mainly nausea) were common.
- Smaller studies confirmed weight benefits, but glucose effects were variable.
Semaglutide Trials
- Early trials suggest semaglutide may improve time-in-range and cause significant weight loss in people with T1D, especially those with obesity.
- Some participants developed ketosis (not always full-blown DKA), so safety remains a concern.
- Larger trials (like RESET1) are ongoing.
Since the recent growth of GLP-1 drugs as anti-obesity medications, many people with T1D have been using this class of medication with promising results – both for weight and diabetes management. But they are not yet approved for use purely in T1D.
The Big Picture: Where Do These Medications Fit?
So, should everyone with type 1 diabetes be taking metformin, SGLT2 inhibitors, or GLP-1 agonists? Not yet. Here’s why:
- Insulin is non-negotiable. For people with T1D, there will always be a need for insulin. These drugs used in T2D are add-ons, never replacements.
- Safety is a key issue. Especially with SGLT2 inhibitors, the risk of DKA means careful monitoring is essential.
- Not all benefits are equal. Metformin may help with cholesterol and weight, but not HbA1c. GLP-1s may help more with weight than glucose. SGLT2s help both, but come with risks.
- Approvals are limited. As yet, these drugs are not officially approved for use in T1D, except in very specific cases.
What This Means for You
If you’re living with type 1 diabetes and struggling with weight, insulin resistance, or cardiovascular risk factors, it’s worth having a conversation with your healthcare team about whether one of these medications could be helpful.
A specialised clinician can advise on the benefit for your blood sugar patterns, weight and various other risk factors which as heart or kidney disease. They will then balance this benefit with the associated and potential risks and ensure the correct monitoring and education takes place.
Looking Ahead
Research into type 2 medications for type 1 is still relatively new, but it’s moving fast. The hope is to broaden the toolkit for people with T1D so that insulin doesn’t have to do all the heavy lifting. Managing diabetes is more than just glucose control, it’s about quality of life and long-term health – if there are additional medications that can alleviate the process, they can and should be considered.
Every person with diabetes is different. What works for one person may not be right for another. If you’re interested in these therapies, ask your IDS clinician and discuss the options that may benefit you.
