Adverse kidney effects?

I was just looking at the phase 2 trial data and they do not show any negative kidney impact. In fact retatrutide seems to have a bigger positive effect than tirzepatide. It produced a marked drop in UACR in both diabetic and non-diabetic patients and unexpectedly raised eGFR and cystatin-C based GFR by 8-10 ml/min in non-diabetics. That improvement went away after people stopped the drug. There are now studies underway in overweight or obese people who also have chronic kidney disease, with results due in late 2025 or early 2026. No approved drug has shown such a large GFR increase so far.

Semaglutide and tirzepatide are already viewed as useful treatments in chronic kidney disease because they slow progression of renal failure, second only to SGLT2 inhibitors and blood-pressure control. Retatrutide is not officially recommended yet since it is still unapproved and the big studies that would confirm the same benefit have not finished, but the early signs look promising.

A large share of people with early or moderate kidney disease do not even know they have it. Obesity-related kidney disease, hyperfiltration, and proteinuria are fairly common. I had significant proteinuria about thirty years ago and was worried it would cause lasting harm, but it improved whenever I lost weight and does not appear to have done much permanent damage. That is not true for everyone, and obesity has become one of the more frequent causes of kidney failure. If you are obese and have never had urine protein checked you probably would not know there is an issue. If actual kidney function is already reduced then specialist advice is important. Checking urine protein along with lipids, blood sugar, and blood pressure makes sense for older people with long-term obesity.