Slimming jabs may ease arthritis pain even for non-overweight patients, study finds

A new study published in the Journal of the American College of Rheumatology finds that low doses of semaglutide or tirzepatide, GLP-1 agonists used to treat obesity and type 2 diabetes, can reduce pain in rheumatoid arthritis even among people who are not overweight. While these drugs are not currently approved for arthritis, the research suggests they may have anti-inflammatory effects that extend beyond weight loss.

Researchers reported that participants with a BMI around 27 experienced significant improvements, and the drugs appeared to lower inflammatory activity across the body. Experts cautioned that while the findings are promising, larger trials are needed to confirm benefits in people with higher BMI, which is common among RA patients.

In rheumatoid arthritis, the medications may block production of specific inflammatory cells that trigger flare-ups and also have anti-inflammatory properties. While they are not expected to replace existing treatments, they could be used alongside them to tailor care for RA.

Rheumatology specialists say the results could shift treatment approaches for RA. They note that the drugs would expand options and enable more personalized care, especially for patients who also struggle with obesity.

More than 1.3 million people in the United Kingdom have rheumatoid arthritis, whose main symptoms include joint pain, swelling and stiffness. Weight-loss injections are not currently included in standard RA treatment, though some patients prescribed these drugs for obesity report improvements.

One American patient described as Cassandra Smith, a 30-year-old mother of one, said tirzepatide transformed her RA. Diagnosed three years ago, she often faced days of pain that left her bedbound. Weighing more than 22 stone, she was advised that losing weight would help. After starting tirzepatide nine months ago, inflammation normalized within about three weeks and pain subsided within two weeks, enabling her to resume normal activity.

Experts say the biggest potential benefit may be for RA patients who are also obese, but access remains an issue. James Galloway, a rheumatology researcher at King’s College London, noted that roughly half of patients seen in clinics with RA are obese and that higher dosing and weight-related factors reduce effectiveness of current meds. He said arthritis is not listed as a co-morbidity that qualifies for GLP-1 therapy on the NHS.

NHS guidelines currently require a BMI above 40 and at least four other conditions, such as heart disease or type 2 diabetes, to qualify for these injections. Some clinicians expect policy to change as more data emerge, but more research is needed to determine who could benefit most.

Dr. Lucy Donaldson, director of research at Versus Arthritis, urged caution. She noted that evidence on how weight-loss injections interact with existing RA treatments is limited and that any decision to use them should be made with medical supervision and alongside lifestyle changes.

Researchers emphasize that ongoing studies will be needed to confirm the findings and to understand how GLP-1 agonists fit with current RA therapies before any policy changes.