Effects of weight-loss medicines on kidney

Weight-loss medicines like Semaglutide (GLP 1RA), originally developed to help people with type 2 diabetes manage their blood sugar, have recently become popular for their ability to cause significant weight reduction. But with their growing use, concerns have also emerged about their impact on kidney health. For people with diabetes, obesity, or chronic kidney disease, these medicines have shown potential protective effects on the kidneys. It helps by: Lowering blood sugar, blood pressure Reducing inflammation and body weight Improving kidney function markers like albuminuria and slowing eGFR decline In fact, the FLOW Phase 3b trial found that Semaglutide reduced the risk of kidney failure and cardiovascular death in patients with type 2 diabetes and chronic kidney disease. These positive results even led to expanded FDA approval in 2025, allowing its use to protect the kidneys in certain diabetic patients. The risk side: While long-term studies show benefits, there have been rare reports of Acute Kidney Injury (AKI), usually linked to severe dehydration caused by nausea, vomiting, or diarrhoea. When patients lose too much fluid, the kidneys dont get enough blood flow, leading to temporary kidney injury. This is why doctors stress the importance of: Staying hydrated Stopping the drug temporarily if severe GI side effects occur Monitoring kidney function, especially in older adults or those already at risk Why are doctors cautious about weight-loss use? Although these medicines are now used widely for weight management, medical supervision is crucial. The FDA has warned against compounded or unapproved weight loss versions of Semaglutide that are being sold online; these can have inconsistent doses and unknown side effects. For those without diabetes, these drugs can aid weight loss, but they should never be used as a quick-fix solution without professional guidance. Semaglutide, significantly reduces the progression of chronic kidney disease and major kidney-related events, offering new hope for patients with diabetes and obesity at risk of kidney failure, according to recent clinical trials. However, caution and monitoring are advised for patients experiencing volume depletion. Practical medical advice Check kidney function (eGFR/creatinine) before starting any weight loss medicine. Watch for persistent vomiting or diarrhoea these can cause dehydration and kidney stress. Avoid unregulated or compounded Semaglutide use only approved prescriptions. Monitor kidney health if symptoms occur or if youre at higher risk. The bottom line Weight-loss medicines like Semaglutide have changed the way we manage diabetes and obesity, offering better blood sugar control and even kidney protection. But as their use expands beyond diabetes, careful monitoring is key. These medicines can help your kidneys or harm them, depending on how theyre used. Always use them under medical supervision. (The writer, Dr Navinath Mohan is a consultant and a nephrologist at Asian Institute of Nephrology and Urology Hospital (AINU), Chennai)