The short answer: For most people, the evidence so far does not show that Mounjaro (tirzepatide) harms the kidneys. The FDA label does carry one kidney warning: acute kidney injury has been reported, mostly in people who became dehydrated from nausea, vomiting, or diarrhea. Trial analyses point the other way for long-term kidney markers, with less protein in the urine and a slower decline in filtering rate. No completed trial has yet tested Mounjaro against placebo for kidney failure as its main goal.

What does the Mounjaro label warn about for kidneys?

The Mounjaro prescribing information (revised August 2026) has a section titled "Acute Kidney Injury Due to Volume Depletion." Volume depletion means the body has lost too much fluid.

The label says there have been postmarketing reports of acute kidney injury in patients treated with GLP-1 receptor agonists or Mounjaro. Some of those cases needed hemodialysis. Most reported events happened in patients whose nausea, vomiting, or diarrhea led to dehydration.

Two points about that wording matter:

  • These are postmarketing reports. They come from use after approval, not from a controlled trial. The label gives no rate for them, so nobody can state how often this happens.
  • The warning describes a route through fluid loss. It ties most cases to dehydration from stomach and bowel side effects.

The label tells prescribers to monitor kidney function in patients who report side effects that could cause fluid loss, especially when starting the drug and when raising the dose. The Zepbound prescribing information, which covers the same drug for weight management, carries the same warning.

How common are the side effects that cause dehydration?

They are common. In the label's pool of two placebo-controlled trials in adults with type 2 diabetes, the share of patients reporting each reaction was:

  • Nausea: 12% to 18% across the 5 mg, 10 mg, and 15 mg doses, against 4% on placebo.
  • Diarrhea: 12% to 17%, against 9% on placebo.
  • Vomiting: 5% to 9%, against 2% on placebo.

The label states that most reports of nausea, vomiting, and diarrhea occurred during dose escalation and decreased over time. Between 3.0% and 6.6% of Mounjaro patients stopped treatment because of gastrointestinal reactions, against 0.4% on placebo.

The label links the kidney risk to the episodes that cause dehydration, not to every bout of nausea. Our side effects management guide covers practical ways to handle those weeks. The label's step-up schedule is explained in the Mounjaro dosing schedule.

Does kidney disease change the Mounjaro dose?

No. The label's renal impairment section says no dosage adjustment is recommended for patients with renal impairment. It reports no change in how the body handles tirzepatide in people with renal impairment, including end-stage renal disease.

That finding comes from a study of a single 5 mg dose in people with mild, moderate, and severe renal impairment and end-stage renal disease, compared with people with normal kidney function.

The same section adds a caution. Prescribers should monitor kidney function when starting or raising the dose in patients with renal impairment who report severe gastrointestinal reactions. "No dose change" is a statement about drug levels. It does not mean reduced kidney function removes the dehydration risk.

What do the trials show for kidney markers?

Two lab tests define kidney health. According to NIDDK, the glomerular filtration rate (GFR) shows how well the kidneys filter blood, and a GFR of 60 or more is in the normal range. The urine albumin-to-creatinine ratio (UACR) shows protein leaking into urine, and 30 mg/g or less is normal.

Three published analyses report on those markers. Eli Lilly, the maker of Mounjaro, funded the two SURPASS analyses below.

SURPASS-4 (type 2 diabetes, compared with insulin glargine). This post hoc analysis covered 1,995 treated adults at high cardiovascular risk. Estimated GFR (eGFR) fell by 1.4 mL/min per 1.73 m2 per year on tirzepatide and by 3.6 mL/min per 1.73 m2 per year on insulin glargine. UACR rose 36.9% on insulin and did not rise on tirzepatide. A composite kidney endpoint was less frequent with tirzepatide (hazard ratio 0.58, 95% CI 0.43 to 0.80).

SURMOUNT-1 and SURMOUNT-2 (overweight or obesity, compared with placebo). This post hoc analysis found that UACR at week 72 was 8.4% lower than placebo in people without diabetes and 31.1% lower in people with type 2 diabetes. The authors concluded that tirzepatide reduced albuminuria without adverse changes in eGFR.

SURPASS-CVOT (type 2 diabetes with cardiovascular disease, compared with dulaglutide). This pre-specified exploratory analysis followed 13,165 participants for a median of 4.0 years. The composite kidney outcome occurred in 6.0% of the tirzepatide group and 7.6% of the dulaglutide group (hazard ratio 0.77, 95% CI 0.68 to 0.88). The annual eGFR decline was slower with tirzepatide by 0.29 mL/min per 1.73 m2. Nausea, vomiting, and diarrhea were more common with tirzepatide.

What is not yet known?

Several gaps remain.

  • The kidney findings are secondary. Two analyses were post hoc and one was exploratory. None came from a trial designed with kidney outcomes as the primary goal.
  • The comparators were other treatments. SURPASS-4 compared tirzepatide with insulin and SURPASS-CVOT compared it with dulaglutide. Neither shows the effect against placebo on kidney failure.
  • Much of the benefit is in lab markers. In SURPASS-CVOT, new-onset macroalbuminuria and slower eGFR decline drove the result. Whether that means fewer people need dialysis is not established.
  • The dedicated kidney trial has no posted results. TREASURE-CKD is a phase 2 trial of tirzepatide against placebo in 134 adults with overweight or obesity and chronic kidney disease. Its primary outcome is change in renal sinus fat on MRI at week 52. ClinicalTrials.gov lists it as completed in July 2026, with no results posted when we checked in October 2026.
  • The label does not claim kidney protection. Mounjaro is not approved to treat or prevent kidney disease.

Who should be most careful?

The label's monitoring advice centers on two situations: dose initiation and escalation, and existing renal impairment combined with severe gastrointestinal reactions. If either applies to you, ask your prescriber how and when your kidney function will be checked.

The label also tells prescribers what to tell patients:

  • Take precautions to avoid fluid depletion.
  • Promptly report signs of acute kidney injury.
  • Promptly report persistent or extended nausea, vomiting, or diarrhea.

NIDDK advises yearly kidney testing for people with diabetes. People with high blood pressure, heart disease, or a family history of kidney failure should ask how often to test. Fluid loss also affects blood pressure. See Mounjaro and blood pressure, and hypertension.md for background on high blood pressure.

Do not stop or change a prescribed dose on your own. A prescriber who knows your eGFR and UACR can judge your risk.

The bottom line

The label warns about one kidney problem: acute kidney injury linked to dehydration from stomach and bowel side effects. It recommends no dose change for reduced kidney function. Trial analyses show lower urine albumin and slower eGFR decline with tirzepatide than with insulin glargine or dulaglutide. A placebo-controlled answer on kidney failure does not exist yet. Stay hydrated, report vomiting or diarrhea that does not settle, and keep your kidney tests on schedule.

Last updated: October 2026. This article is for informational purposes only and does not constitute medical advice. Talk with your prescriber about your kidney function and any symptoms before changing how you take Mounjaro.