A widely used diabetes drug may soon play a surprising new role: easing the pain of knee osteoarthritis in people who are overweight or obese. A study led by Monash University has found that metformin, commonly used to treat type 2 diabetes, can reduce knee pain in people with osteoarthritis, even if they don’t have diabetes.
The results suggest that this affordable and familiar medication could help delay knee replacements, improving quality of life for many patients.
The clinical trial, published in JAMA, involved 107 adults with painful knee osteoarthritis. None of the participants had diabetes, but all were overweight or obese.
They were randomly assigned to either take metformin—up to 2,000 mg per day—or a placebo for six months. The study was conducted fully online and by phone, making it accessible to people living outside major cities.
Participants rated their knee pain on a 0 to 100 scale, with 100 being the most severe. By the end of the trial, the metformin group saw their pain scores drop by an average of 31 points. The placebo group, by comparison, only saw a reduction of about 19 points. The improvement in the metformin group was considered moderate but meaningful.
Professor Flavia Cicuttini, the lead researcher and Head of the Musculoskeletal Unit at Monash University, said these results show that metformin could offer a new, cost-effective way to manage knee osteoarthritis pain in people with excess weight. This is especially important because current treatment options are limited.
Standard treatments like exercise and weight loss can be effective, but many people find them difficult to stick with. Medications such as paracetamol or anti-inflammatory creams and pills offer only mild relief, and some carry risks or can’t be used long term. No new drug for osteoarthritis has been approved in Australia since the late 1990s.
Because of the lack of good options, some patients—and their doctors—turn to knee replacement surgery earlier than needed. However, many patients who undergo the surgery for early-stage osteoarthritis remain unhappy with the results.
In fact, up to 30% of people are dissatisfied after a knee replacement, even when the procedure goes smoothly. When the surgery is done too early, it also raises the chance that the joint will need to be replaced again later—which is more expensive and less likely to have good results.
Professor Cicuttini believes metformin could offer general practitioners a helpful new tool for managing knee pain, one that is already familiar, safe, and inexpensive. Metformin works differently than typical pain medications.
It targets low-level inflammation and other body processes that contribute to osteoarthritis, offering a new approach to treatment. If patients feel less pain, they may also be more able to exercise and improve their overall health, further delaying the need for surgery.
The research team is now working with doctors, surgeons, and patients to figure out how best to include metformin in the standard treatment plans for knee osteoarthritis. While the drug is not yet officially approved for this use, doctors could consider prescribing it “off label” after talking with their patients about the risks and benefits.
Importantly, the study also shows that metformin can be safely provided through telehealth, making it easier to access for people in rural or remote areas.
In summary, metformin—a drug long used to control blood sugar in diabetes—may now offer hope to people with knee osteoarthritis. It could help reduce pain, improve movement, and delay the need for joint replacement surgery, all with a low-cost, well-known medication that can be safely used even without diabetes.
If you care about blood sugar, please read studies about why blood sugar is high in the morning, and how to cook sweet potatoes without increasing blood sugar.
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The research findings can be found in JAMA.
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