Metformin’s Latest Plot Twist: A Link to Better Survival After COVID
Metformin may be due for a longer job description.
The familiar diabetes medication helps manage blood sugar. Now researchers are investigating whether it could also help people with type 2 diabetes fare better after COVID-19. A recent report from the University of Minnesota’s Center for Infectious Disease Research and Policy, or CIDRAP, highlights the possibility. [1]
In a study published November 5th in Diabetes, Obesity and Metabolism, people prescribed metformin had a 39% lower adjusted risk of dying from any cause during the year after COVID than people prescribed another class of diabetes medication, DPP-4 inhibitors. That is a relative reduction in risk—not a 39-percentage-point drop. [2]
Researchers examined health records from 53,332 U.S. adults with type 2 diabetes who had COVID between October 2021 and November 2023. The patients had been prescribed their diabetes medication at least 30 days before infection. The study therefore looked at existing prescriptions; it did not test starting metformin after a positive COVID test. [2]
Before we give metformin a superhero cape, there is some fine print.
This was an observational study. The people taking DPP-4 inhibitors tended to be older and have more health problems. Researchers adjusted for differences between the groups, but adjustments cannot erase every possible difference. Vaccination records were also incomplete. The results show a promising association, while leaving open whether metformin itself caused the better outcomes. [1]
The long-COVID findings were more complicated. Metformin users had a 13% lower adjusted risk of “probable” long COVID, identified through a model that examined patterns in medical records. But the difference in formally recorded long-COVID diagnoses was not statistically significant. The two measures tell a more cautious story than a simple claim that metformin prevents long COVID. [2]
There are plausible reasons for scientists to keep investigating. Better blood sugar control may support the body’s response to infection. Researchers are also exploring metformin’s effects on inflammation and the virus’s ability to multiply. These are possible explanations for a benefit; this study did not establish which mechanism, if any, accounted for the survival difference. [1]
The research received funding from the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health. [2]
For people living with diabetes, the practical response is to keep medication decisions with their care team. This finding alone is not a reason to start metformin or switch diabetes drugs.
If COVID symptoms appear, seek advice promptly about established antiviral treatments. CDC guidance emphasizes that eligible patients need to start treatment within five to seven days of symptom onset, depending on the medication. Metformin should not take the place of that timely evaluation and treatment. [3]
Sources
Information checked November 12, 2026.
[2] Dozier et al. “Metformin and Severe Post-COVID-19 Outcomes Among Individuals With Diabetes Mellitus.” Diabetes, Obesity and Metabolism. Published November 5, 2026. DOI: 10.1111/dom.71502.
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