Ozempic’s key ingredient fixes faulty filters in the kidney.
The well-known weight loss drug repairs and restores blood vessels that power people’s waste disposal systems, researchers report October 1 in Nature Medicine. Those actions mean the ingredient, called semaglutide, can add another notch to its list of health benefits: treating chronic kidney disease.
In patients with the condition, semaglutide also increased blood flow and tamped down inflammation, the team found. The study reinforces the GLP-1 drug’s known anti-inflammatory effects, while also suggesting that it may play a direct role in protecting the kidney’s blood vessels, says Susan Quaggin, a nephrologist at Northwestern University Feinberg School of Medicine in Chicago who was not involved in the work.
Chronic kidney disease affects an estimated 674 million people worldwide, with some of the most common causes being diabetes and high blood pressure. As the disease progresses, the kidneys slowly lose their ability to filter out waste from blood and excrete it as urine. This causes other health complications, as well as a sharply increased risk of dying from a heart attack or stroke.
Patients with diabetic chronic kidney disease who took semaglutide were less likely to wind up in kidney failure, or die from a heart attack or stroke, than those taking a placebo, researchers reported in 2024 in the New England Journal of Medicine. That trial was stopped early, as the drug was so effective at preventing death that doctors no longer considered it ethical to keep giving participants the placebo.
For the new study, some of those same researchers then looked at a subset of 106 participants to find out how the drug worked. The team collected kidney tissue samples before and after the participants took semaglutide, and compared them with samples from participants given the placebo. Semaglutide use led to striking visible changes in the tissues, including increased blood flow, reduced scarring and reduced blood vessel stiffness, a measure of vessel health.
Increased blood flow is important because it increases filtration, which is the kidneys’ main job, says Peter Nguyen, a nephrologist at Houston Methodist Hospital who was not involved in the study.
Researchers also looked at levels of a protein, called albumin, in patients’ urine. High levels can be an early sign that the kidneys’ filters aren’t working well. While those levels didn’t change much in those on the placebo, they dropped in patients taking semaglutide ― a sign the filters weren’t quite as leaky any more.
The team then looked under the hood for genetic clues to how semaglutide appeared to heal the kidneys. Within the glomerulus, the tiny blood vessels responsible for the kidney’s filtering action, genes relating to metabolic stress were turned off, Katherine Tuttle, a nephrologist at the University of Washington’s Providence Medical Research Center in Spokane, and colleagues found. Within these same cells, inflammatory genes were also turned off, while repair genes were switched on.
The researchers also looked at a subset of genes responsible for cells “talking” to each other within the glomerulus. Before semaglutide, the blood vessels and immune cells were “chattering” with each other, sending lots of inflammatory signals, Tuttle says. After semaglutide, the immune cells went quiet, silencing the messages that ramp up harmful inflammation. These changes in gene activity point to a healthier kidney that’s less stressed and inflamed, and that has had repair processes flipped on.
With semaglutide treatment, Tuttle says, patients’ damaged kidneys showed clear signs of repair.
