Semaglutide may help knee pain in adults who also have obesity. Osteoarthritis is joint disease affecting cartilage, the smooth covering on bone ends, and nearby tissues. The main semaglutide knee osteoarthritis trial found greater average pain and weight reductions than placebo, an inactive comparison shot.
That study, STEP 9, did not establish cartilage repair. It also couldn't separate the effects of losing weight from a possible direct effect on the joint. Less pain is a useful finding, but it doesn't tell us everything about what changed inside the knee.
Semaglutide knee osteoarthritis: what STEP 9 found
STEP 9 enrolled 407 adults for 68 weeks, or about 16 months. They had obesity, moderate knee osteoarthritis confirmed by examination and X-rays, and at least moderate pain. Their body mass index (BMI), a measure of weight relative to height, was at least 30. The average age was 56.
Participants were assigned by chance to semaglutide or placebo. The semaglutide group received a weekly injection, gradually increased toward 2.4 mg. Both groups received advice about a reduced-calorie diet and physical activity. These are study details; a prescriber sets an individual's dose.
WOMAC is a questionnaire about arthritis pain, stiffness and everyday movement. Its scores in this trial ran from 0 to 100, with higher numbers meaning worse symptoms.
The results came from Bliddal and colleagues in the New England Journal of Medicine, 2024:
| Average change at 68 weeks | Semaglutide | Placebo |
|---|---|---|
| Body weight | −13.7% | −3.2% |
| WOMAC pain score | −41.7 points | −27.5 points |
| WOMAC physical-function score | −41.5 points | −26.7 points |
The paper's estimated pain-score difference was 14.1 points in semaglutide's favor. That estimate came from a calculation comparing the groups. It differs slightly from subtracting the rounded averages above. Both groups improved, which is why the comparison matters more than the semaglutide number alone.
Was the pain change just from losing weight?
Weight loss is likely a major part of the explanation. Less body weight means less mechanical load on the knees. The STEP 9 authors also noted possible effects on inflammation, the body's response to injury or irritation.
The trial did not include a comparison group that lost the same amount of weight through another method. It therefore couldn't measure how much pain relief came from weight loss and how much came from other effects of semaglutide.
There was no follow-up imaging to assess cartilage changes. The trial also didn't measure inflammatory markers, blood measurements that can help track inflammation. Its strong finding concerns symptoms and weight, rather than a demonstrated change in joint structure.
What newer knee studies add
As of September 30, 2026, the day this article was written, two 2026 reports add detail without settling that distinction.
A Cell Metabolism paper first published February 9 reported joint effects in mice beyond weight loss. It also included a 20-person pilot, a small early study, in which everyone received hyaluronic-acid knee injections and half also received weekly semaglutide injected under the skin, at a low 0.5 mg dose. Physical function improved more with semaglutide, but pain did not clearly differ between groups. Participants receiving semaglutide also lost weight, leaving the direct-effect question open in people.
A July 27 report by Conforti and colleagues in Journal of Clinical Medicine reviewed 93 adults treated in routine care. Eighty-eight completed six months; their average pain score fell 2.47 points on a 0–10 scale. There was no untreated comparison group. The authors explicitly said these observations cannot establish that semaglutide caused the changes or acted independently of weight loss.
That pain scale differs from STEP 9's WOMAC scale. The figures cannot be compared as though they measured the same thing.
What are the side-effect trade-offs?
In STEP 9, about 7 in 100 people receiving semaglutide stopped because of side effects, compared with 3 in 100 receiving placebo. The reported figures were 6.7% and 3.0%. Stomach and bowel problems were the most common reason for stopping.
Serious adverse events, medical problems recorded during the trial, occurred in 10.0% and 8.1%, respectively. The paper described their frequency as similar. These problems were not necessarily caused by treatment.
The study collected selected safety events rather than every mild symptom. It therefore doesn't supply a complete nausea or constipation rate for this population.
The broader semaglutide side-effects guide covers those common symptoms. A provider also weighs pancreas and gallbladder history, dehydration risk, pregnancy plans and other medicines.
What does this mean for a prescription?
As of September 30, 2026, the day this article was written, the Wegovy label on FDA's site says Revised: 06/2026. Weight management is a listed use; knee osteoarthritis is not a separate listed use. A trial finding and a prescribing label answer different questions.
Compounding means a pharmacy prepares medicine for an individual prescription. Through Promise, semaglutide is dispensed as a compounded medication, which is different from an FDA-approved product: the formulation offered here is not FDA-approved.
STEP 9 studied a manufactured trial injection, not Promise's preparation. Its percentages cannot be promised for a compounded prescription. The compounded semaglutide explainer covers that distinction in more detail.
A licensed provider may still prescribe a compounded formulation; that decision is between the patient and the doctor.
What about BPC-157 and other joint peptides?
BPC-157 is another peptide, a short chain of protein building blocks, that people ask about for joint pain. Its human evidence is much thinner.
A 2021 report by Lee and Padgett reached 16 people by phone after knee injections. Four had also received another peptide. Fourteen reported improvement, but there was no control group or standard questionnaire measuring the change. That cannot establish an osteoarthritis treatment effect or cartilage repair.
The peptides-for-joint-pain overview explains the evidence behind those other compounds. They do not inherit STEP 9's findings simply because they are also peptides. Gout is a different kind of joint pain, and whether GLP-1 medicines change its risk is a separate question — see semaglutide and gout.
What a provider needs to know
A useful visit connects two questions: whether weight treatment fits the person's health history, and what is causing the knee pain. STEP 9 studied adults with obesity and moderate knee osteoarthritis. It cannot establish the same results for a person without obesity or with a different knee condition.
The review includes medullary thyroid carcinoma, a particular thyroid cancer, in the person's own or family history. The Wegovy label rules out use with that history, MEN 2, an inherited tumor condition, or a previous serious allergy to semaglutide.
At Promise, a licensed provider reviews every request, and not everyone qualifies. Follow-up can track walking, stairs, pain and medication tolerance alongside weight. Established knee care, including appropriate exercise and rehabilitation, remains part of that conversation.
