The drug semaglutide is already proving incredibly effective in tackling diabetes (under the brand name Ozempic) and weight loss (as Wegovy), and a new study suggests it can do wonders for a type of crippling knee pain too.

In a phase 3 clinical trial, an international team of researchers found that a weekly dose of 2.4 milligrams of semaglutide significantly beat placebo treatments for relieving knee osteoarthritis pain, reducing weight, and improving the ability to complete physical activities like walking.

For some participants, the pain reduction was so drastic that they were effectively “treated out of the study”, rheumatologist Henning Bliddal, from Copenhagen University Hospital in Denmark, told Nature. It’s a ray of hope for the hundreds of millions of people living with knee osteoarthritis.

The arthritic condition is brought on when the protective cartilage in the knee joints gets worn away, causing pain and stiffness that can be quite severe. Obesity is a major risk factor for knee osteoarthritis, and losing weight can help reduce the pain – two good reasons why the researchers wanted to look at semaglutide.

Semaglutide is what’s known as a glucagon-like peptide-1 receptor agonist (GLP-1RA): essentially, it mimics the GLP-1 hormone that gets produced when we eat, and tricks the brain into thinking we’re full.

That’s going to help with weight loss, but the drug also works as an anti-inflammatory, calming down overreactions from the body’s immune system that trigger swelling and tissue damage – which helps to explain the reduction in pain.

On average, body weight dropped 13.7 percent in the group given semaglutide compared to 3.2 percent given placebos, while the reported pain scores dropped 41.7 points and 27.5 points respectively (the pain scale used runs from 0 to 96).

There are a few caveats to drop in here: the study was partly funded by Novo Nordisk, which manufactures semaglutide. Also, while participants were given advice about diet and physical activity routines during the trial, there were no checks on how much of this advice was followed.

It’s also worth bearing in mind that semaglutide in its various forms is an expensive drug, and that weight can quickly pile back on when doses are stopped. Getting people to take the drug long term could be challenging.

Despite those issues, the study results offer plenty of early promise for a future treatment for knee osteoarthritis and the debilitation that goes along with it. There are treatments currently available, but they often come with limitations or side effects.

Those with the condition are often caught in a bind: knowing that physical activity and exercise can help them lose weight and improve their symptoms, but also being in too much pain to actually do anything about it.

“Weight reduction along with physical activity is often a recommended approach to managing painful symptoms, but adherence can be challenging,” says Biddal.

The research has been published in the New England Journal of Medicine.