Can GLP-1 Drugs Prevent Type 2 Diabetes? What a 3-Year Trial Showed
Tirzepatide reduced the risk of developing type 2 diabetes by 94% in adults with prediabetes in a 3-year clinical trial. Here is what that means for patients.
Prediabetes affects an enormous number of people - approximately 96 million adults in the United States alone. Most receive lifestyle advice and monitoring. Very few receive medication specifically aimed at stopping progression to type 2 diabetes.
Data from a 3-year extension of the SURMOUNT-1 clinical trial changes that conversation significantly.
What the trial found
The SURMOUNT-1 trial originally studied tirzepatide (Mounjaro/Zepbound) for weight loss in adults with obesity. A subset of 1,032 participants in that trial also had prediabetes at the start.
Eli Lilly extended the trial to 176 weeks - approximately 3.4 years - to measure the impact on diabetes progression. Results were announced in August 2024.
The finding:
Tirzepatide reduced the risk of progressing from prediabetes to type 2 diabetes by 94% compared to placebo.
That is not a modest effect. For context, the landmark Diabetes Prevention Program - the gold standard lifestyle intervention - reduced diabetes risk by 58% over 3 years. Tirzepatide more than doubled that result.
The full numbers
Participants took weekly tirzepatide injections at 5 mg, 10 mg, or 15 mg for 176 weeks:
| Dose | Weight loss at 176 weeks | Diabetes risk reduction |
|---|---|---|
| 5 mg | 15.4% | 94% (pooled doses) |
| 10 mg | 19.9% | 94% (pooled doses) |
| 15 mg | 22.9% | 94% (pooled doses) |
| Placebo | 2.1% | - |
After stopping the medication (17-week follow-up), the risk reduction fell to 88% - suggesting some protection persisted briefly but that continued treatment is needed to maintain the benefit.
Why does this happen?
The mechanism is primarily weight loss. Excess body fat, particularly visceral fat around the organs, is a central driver of insulin resistance - the root cause of type 2 diabetes. Reducing body weight by 15–23% substantially reduces insulin resistance and allows the pancreas to function more effectively.
GLP-1 medications also directly stimulate insulin secretion from the pancreas in a glucose-dependent manner and suppress glucagon, which further improves blood sugar regulation.
Together, these effects give the pancreatic beta cells a chance to recover and function normally - which may explain why some participants saw sustained benefit even after stopping.
What this means for patients with prediabetes
If you have prediabetes and obesity or overweight, this data is directly relevant to your situation. A conversation with your doctor about GLP-1 therapy - particularly tirzepatide - is worth having.
Questions to bring:
- Is my HbA1c and fasting glucose trend moving toward diabetes?
- Given my weight and prediabetes status, would tirzepatide be appropriate?
- Is there insurance coverage for this use, or what are the self-pay options?
- What lifestyle changes should accompany medication?
What about semaglutide (Ozempic/Wegovy)?
Semaglutide has not been studied in a dedicated 3-year prediabetes prevention trial. However, observational data and sub-analyses from the SELECT cardiovascular outcomes trial suggest meaningful reductions in diabetes incidence in semaglutide users. Formal prediabetes prevention trials for semaglutide are likely in the future.
Tracking prediabetes markers
If you are on GLP-1 therapy and have prediabetes, regular HbA1c and fasting glucose checks - typically every 3–6 months - tell the story of whether the medication is working metabolically beyond just weight loss. Keeping a consistent log of weight and medication history makes it easier to correlate those blood results with your treatment pattern.
Final takeaway
A 3-year extension of the SURMOUNT-1 trial showed tirzepatide reduced the risk of prediabetes progressing to type 2 diabetes by 94%. This is a landmark result that significantly outperforms lifestyle intervention alone. Using GLP-1 drugs specifically for prediabetes prevention is off-label, but the data is compelling enough that it warrants a detailed conversation with your doctor.
Consult your healthcare provider before starting any medication.
Sources
- Eli Lilly SURMOUNT-1 3-year extension results: press release, August 20, 2024
- Knowler WC, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med. 2002;346:393–403 (Diabetes Prevention Program)
- Zepbound prescribing information - Eli Lilly
- Tirzepatide FDA history: drugs.com/history/zepbound.html
FAQ
Can Ozempic or Mounjaro prevent type 2 diabetes?
Clinical trial evidence is strong for tirzepatide (Mounjaro/Zepbound). A 3-year SURMOUNT-1 extension showed tirzepatide reduced the risk of progression from prediabetes to type 2 diabetes by 94% compared to placebo. Semaglutide data also shows risk reduction, though the trial specifically using GLP-1 for prediabetes was done with tirzepatide.
Is Mounjaro or Ozempic approved for prediabetes?
Not specifically. GLP-1 medications are approved for type 2 diabetes (Ozempic, Mounjaro) and obesity (Wegovy, Zepbound). Using them specifically for prediabetes prevention is off-label, though the clinical evidence is compelling.
How long do you have to take GLP-1 for diabetes prevention?
In the SURMOUNT-1 trial, participants took tirzepatide for 176 weeks (approximately 3.4 years). When the drug was stopped, diabetes risk began to return - suggesting the benefit requires continued treatment.
What is prediabetes?
Prediabetes is a condition where blood sugar levels are higher than normal but not yet high enough to be classified as type 2 diabetes. HbA1c of 5.7–6.4% or fasting glucose of 100–125 mg/dL typically indicates prediabetes. It affects approximately 96 million American adults.