Weight-Loss Drug Also Shows Promise for Knee Pain

A next-generation weight-loss drug being tested by Eli Lilly is showing major results in clinical trials, including a possible added benefit for people with knee osteoarthritis.

The drug, called retatrutide, helped participants in one 68-week trial lose an average of 28.7% of their body weight at the highest dose, according to results announced by Eli Lilly.

Retatrutide works differently from current drugs by targeting three hormone pathways: GLP-1, GIP, and glucagon. Researchers say that the combination may help reduce appetite while also increasing energy use.

The surprising finding came in a study involving adults with obesity and knee osteoarthritis. Some participants reported major reductions in knee pain, and researchers suggested the drug may do more than reduce joint stress through weight loss. It may also have anti-inflammatory effects.

Retatrutide is not yet approved by the FDA and is not legally available. Eli Lilly is expected to seek approval in late 2026 or early 2027.