On Metformin for Prediabetes and Not Seeing the Results You Want? A New Study Says You May Have Options
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If you have prediabetes, there's a good chance metformin was the first drug you were offered, and maybe the only one. It's cheap, safe for most people and has been studied for decades. But if you've been taking it for a while and your blood sugar or weight hasn't moved the way you hoped, a study released on November 2 gives you something new to talk about with your doctor.
In that study, adults with prediabetes and obesity who took a GLP-1 were less likely to get type 2 diabetes than those on metformin (American Heart Association). It's early research with real limits. Below, we'll walk through what it found, what current guidelines say, and the questions to bring to your next visit.
Who This Helps
This is for anyone with prediabetes, or type 2 diabetes, who's taking metformin and wondering whether there's another path. It isn't a treatment plan. Any decision to add, switch or stop a drug is one to make with your prescriber.
What did the new study find?
Researchers looked at health records for 256,492 adults with prediabetes and obesity over about three years. About half took a GLP-1 and about half took metformin. The GLP-1 group was 1.5 times as likely to see their blood sugar return to a normal range, and 31% less likely to develop type 2 diabetes. They also had fewer heart attacks, strokes and cases of heart failure. The study didn't single out people whose metformin wasn't working. It just compared the two drugs (American Heart Association).
Those are good numbers, but keep a few things in mind. This was a records study, not a randomized trial, so it can show a link but can't prove the GLP-1s caused the difference. It was presented as a conference abstract and hasn't been peer reviewed yet. It also lumped several GLP-1s together, so it can't tell you which one works best.
The lead researcher, Dr. Vinicius Serra of Mayo Clinic, was careful about what it means. "This is less about replacing one medication with another and more about discussing additional options with specific patients," he said (AJMC).
Why is metformin usually the first choice?
For prediabetes, metformin has the strongest long-term evidence. In the Diabetes Prevention Program, a large federal trial, people who took metformin were 31% less likely to develop type 2 diabetes than people taking a placebo (NIDDK). That same trial found that people in its diet and exercise program did even better, with a 58% lower chance of developing diabetes.
The American Diabetes Association says metformin should be considered for adults at high risk, especially those aged 25 to 59 with a BMI of 35 or higher. It also points to people with higher blood sugar readings and women who had diabetes while pregnant. And it notes there isn't long-term data supporting any other drug just for preventing diabetes (ADA Standards of Care 2026).
Metformin also isn't a weight-loss drug. The ADA describes its effect on weight as neutral, with "potential for modest loss" (ADA Standards of Care 2026). So if you started it hoping the scale would move, a flat result doesn't mean you did something wrong.
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Where do GLP-1s fit for prediabetes?
No GLP-1 is approved for prediabetes itself. Neither is metformin, for that matter; it's approved for type 2 diabetes, and doctors prescribe it for prediabetes off-label (StatPearls). What some GLP-1s are approved for is weight. Wegovy and Zepbound are approved for adults with obesity, or with overweight plus at least one weight-related health condition (Zepbound label).
For people with overweight or obesity, the ADA says using GLP-1 drugs to manage weight is "highly beneficial and should be considered." It also notes that several weight-loss drugs have been shown to lower the odds of getting type 2 diabetes in people with prediabetes (ADA Standards of Care 2026). So if you have prediabetes and your weight is also a concern, a GLP-1 may belong in the conversation. If weight isn't a concern for you, metformin and changes to diet and exercise are still the main tools.
What if you have type 2 diabetes?
The picture shifts a little once you've been diagnosed. A new report from the American and European diabetes associations, published in October, says GLP-1s can be considered early, potentially from diagnosis, for some people with heart or kidney risk or weight goals (Diabetes on the Net).
In one large trial of people whose diabetes wasn't under control on metformin, adding Mounjaro or Ozempic lowered A1c by about 2 points on average over 40 weeks (Mounjaro label). In that trial, metformin stayed in place. Whether it stays in yours is something your prescriber will decide with you.
What will it cost?
Cost is often what decides this. Metformin is a cheap generic, while GLP-1s cost far more, and coverage depends on your plan and the reason for the prescription. Because prediabetes on its own isn't an approved reason to prescribe a GLP-1, ask your plan how it handles GLP-1s for weight. Our guide to checking a plan for GLP-1 coverage can help.
If you're on Medicare, the temporary GLP-1 Bridge program counts prediabetes as a qualifying condition if your BMI is 27 or higher. It covers Wegovy, Foundayo and the Zepbound KwikPen for a $50 monthly copay, needs prior authorization, and doesn't apply to people with type 2 diabetes (Medicare.gov). Dr. Robert Eckel, a past president of the American Heart Association who wasn't part of the study, put it simply: "costs and access to these medications are important factors" (AJMC).
Questions to ask your prescriber
- Is metformin doing what we hoped? Ask what your A1c or fasting blood sugar was before you started and what it is now. The ADA also recommends checking vitamin B12 from time to time for people on metformin long term.
- Does my weight change the picture? If you also have overweight or obesity, the ADA supports considering a GLP-1 for weight.
- Would a GLP-1 be added or swapped in? In the major diabetes trials, metformin stayed in place.
- What would it cost me? Ask about your plan's rules and any self-pay options.
- What are the trade-offs? GLP-1s carry a warning for people with a personal or family history of medullary thyroid cancer or MEN 2. Stomach side effects like nausea are also common, mostly while the dose goes up.
Whatever you decide, don't stop metformin on your own because of a headline. Bring the study to your next visit and talk it through together with your prescriber.
Final Takeaway
Metformin is still a safe, low-cost first choice for prediabetes, and the lead researcher behind the new study says so too. What the study adds is early evidence that, for people with prediabetes and obesity, GLP-1s may lower the chance of developing diabetes more than metformin does. It isn't proof, and no GLP-1 is approved for prediabetes on its own. But if metformin isn't getting you the results you want, bring it up with your prescriber. Talk about your weight, your heart health and what your plan will cover, too.
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Frequently Asked Questions
Can I switch from metformin to a GLP-1 for prediabetes?
That's a decision for your prescriber. No GLP-1 is approved for prediabetes alone, but some are approved for weight, and the ADA supports considering them for people with overweight or obesity. Don't stop metformin without talking to your prescriber first.
Is metformin a weight-loss drug?
No. The ADA describes its effect on weight as neutral. If losing weight is one of your goals, that's a separate conversation with your prescriber.
Does the new study prove GLP-1s are better than metformin?
No. It found a link in health records, not proof, and it hasn't been peer reviewed. Its lead author said metformin is still a first-line treatment choice.
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Lauren PescarusLauren Pescarus is a team member with GLP Winner where she works on marketing, content creation, and operations. She has over 10 years experience in the content creation space, including in the GLP-1 space where she works to stay on top of access news, research updates, and lifestyle tips guided by science.