GLP-1 medicines, dehydration and acute kidney injury: what the Wegovy, Zepbound and Foundayo labels say

Nausea, vomiting and diarrhea are the most common side effects of GLP-1 medicines, and most people treat them as an inconvenience. The labels add a reason to take them seriously when they are persistent: dehydration can strain the kidneys. This article explains what the Wegovy, Zepbound and Foundayo labels say about acute kidney injury, how often the stomach and bowel reactions that can lead to it occurred in the trials, what the label-based advice looks like in practice, and how to separate this warning from the evidence that semaglutide can protect kidneys in some patients. It is general information for discussion with your prescriber, not a treatment plan.

What the labels say about acute kidney injury

Acute kidney injury (AKI) is a sudden drop in kidney function, as opposed to chronic kidney disease, which develops over months or years. All three labels place the warning in Warnings and Precautions.

The Wegovy label (revised 06/2026), section 5.5, is titled “Acute Kidney Injury Due to Volume Depletion.” It says there have been postmarketing reports of acute kidney injury, in some cases requiring hemodialysis, that the majority of the reported events occurred in patients who experienced gastrointestinal adverse reactions, and that renal function should be monitored in patients reporting adverse reactions that could lead to volume depletion. Section 6.1 adds that some kidney-related adverse reactions occurred in association with gastrointestinal adverse reactions or dehydration.

The Zepbound label (revised 08/2026), section 5.3, says the same about postmarketing reports of AKI, some requiring hemodialysis, and says the majority occurred in patients with gastrointestinal reactions leading to dehydration, such as nausea, vomiting or diarrhea. It also says to monitor renal function in patients reporting adverse reactions that could lead to volume depletion. Section 8.6 says no dosage adjustment of Zepbound is recommended for patients with renal impairment.

The Foundayo label (orforglipron tablets, revised 07/2026), section 5.4, is also titled for AKI due to volume depletion. It describes reports of AKI, in some cases requiring hemodialysis, in patients treated with GLP-1 receptor agonists, says the majority of the reported events occurred in patients who experienced gastrointestinal adverse reactions, and says to monitor renal function in patients reporting reactions that could lead to volume depletion.

Two features of the wording are worth noticing. First, these are described as reports, mostly after the medicines reached the market, so they do not provide a rate. The labels do not state how many patients were affected. Second, the mechanism the labels point to is indirect: the medicine causes stomach or bowel reactions, those cause fluid loss, and the fluid loss stresses the kidneys. That is a different story from a direct toxic effect on the organ.

How common are the stomach and bowel reactions that lead to it?

The warning only makes sense against how often the triggering side effects occur. In the placebo-controlled trials reported in the labels:

• Wegovy (adults, 2.4 mg injection versus placebo): section 6.1 lists nausea at 44% versus 16%, diarrhea at 30% versus 16%, and vomiting at about 24% to 25% versus 6%. The label text and its Table 3 differ by one point for vomiting in the version we retrieved.
• Zepbound (Studies 1 and 2, Table 1): nausea was 25%, 29% and 28% at 5, 10 and 15 mg versus 8% with placebo; vomiting 8%, 11% and 13% versus 2%; and diarrhea 19%, 21% and 23% versus 8%.
• Foundayo (section 6.1): gastrointestinal adverse reactions overall occurred in 60%, 68% and 69% of patients at 5.5 mg, 9 mg and 17.2 mg, versus 37% with placebo. Discontinuation due to GI reactions was 3%, 6% and 6% versus 0.7%. Section 5.3 notes severe gastrointestinal adverse reactions were reported more often with Foundayo.

These figures come from different trials in different populations and should not be read as a ranking of the medicines. The point is narrower: a large share of people have at least some stomach or bowel upset, which means a large share could in principle lose fluid. Most do not develop kidney injury, but the labels ask prescribers to watch for the minority in whom fluid loss becomes significant. For more on the side effects themselves, see what the labels and trials report about oral GLP-1 side effects.

Recognizing dehydration

MedlinePlus, the National Library of Medicine’s patient resource, lists these symptoms of dehydration in adults: strong thirst, a parched mouth, peeing and sweating less than normal, dark urine, dry skin, fatigue and lightheadedness. It says to get medical help right away if symptoms also include confusion, fainting, little or no urination, a rapid heartbeat, rapid breathing or shock (MedlinePlus: Dehydration).

Two of those signs are easy to miss on a GLP-1 medicine. Fatigue and lightheadedness can be put down to eating less, and reduced thirst or appetite can mask how little you have drunk. Dark urine and passing urine much less often are better clues than how you feel. If you are eating and drinking very little because of nausea, the combination of low intake and ongoing losses is what the labels’ warning is about.

What the label-based advice means for everyday decisions

The labels give instructions to clinicians, not a home-care protocol, so there is no label rule for how many glasses of water to drink. What the labels do support is a set of questions to settle with your prescriber in advance.

• Know your trigger point. Ask what level of vomiting or diarrhea, or how many hours without keeping fluids down, should make you call. The label says kidney function should be monitored in people with reactions that could cause volume depletion, which suggests a call is better than waiting.
• Ask about other medicines. Some commonly used medicines affect fluid balance or kidney function. The sections of the labels we reviewed do not list specific medicines in the AKI warning, so ask your prescriber or pharmacist to review everything you take, including over-the-counter pain relievers and diuretics.
• Tell your prescriber about existing kidney disease. Zepbound section 8.6 says no dose adjustment is recommended for renal impairment, but that does not mean kidney history is irrelevant to monitoring.
• Plan around dose changes. Side effects commonly occur when a medicine is started or a dose is increased, so those are good moments to be alert. See common GLP-1 dosage mistakes for related background.
• Do not self-adjust. If you are unable to keep fluids down, call your prescriber rather than deciding alone whether to skip or double a dose.

What if I already have kidney disease?

This is where the evidence needs care. The warning describes harm from dehydration, but there is also trial evidence about kidney protection. The FLOW trial, published in the New England Journal of Medicine in 2024 (Perkovic and colleagues), randomly assigned 3,533 patients with type 2 diabetes and chronic kidney disease to once-weekly semaglutide 1.0 mg or placebo. After a median follow-up of 3.4 years, the primary outcome (a composite of kidney failure, at least a 50% fall in eGFR, or death from kidney or cardiovascular causes) occurred less often with semaglutide (331 versus 410 first events; hazard ratio 0.76, 95% confidence interval 0.66 to 0.88). Serious adverse events were reported in a lower percentage of participants with semaglutide than placebo (49.6% versus 53.8%). The trial was funded by Novo Nordisk.

These two facts are compatible. In FLOW, participants were selected, monitored in a trial setting and treated at a studied dose in people with type 2 diabetes and chronic kidney disease, and the trial does not tell you what happens when an individual has days of vomiting. The labels’ warning concerns exactly that scenario. The right takeaway for someone with kidney disease is not to avoid or embrace these medicines on the basis of one headline, but to have a clinician who knows your kidney function decide whether treatment fits, how closely to monitor, and what to do if you become dehydrated. Note that FLOW enrolled people with type 2 diabetes; its results do not automatically apply to people without diabetes taking a medicine for weight management.

What monitoring can look like

The labels say to “monitor renal function” in patients with reactions that could lead to volume depletion. They do not specify a schedule or a test, so any plan is for your prescriber to set. In practice, kidney function is commonly assessed with a blood test of creatinine, from which an estimated glomerular filtration rate (eGFR) is calculated, and sometimes a urine test. If your prescriber orders such tests after a bout of vomiting or diarrhea, that is consistent with the label. If you use a telehealth service, ask how they would handle a request for lab tests and who would review them; a service that cannot answer is not equipped for this part of the label. Our guide to questions to ask a telehealth provider covers related ground.

Common misunderstandings

• “These medicines damage the kidneys directly.” The labels link the reported AKI events to gastrointestinal reactions and dehydration. They do not describe a direct effect on the kidneys.
• “Kidney injury is common.” The labels describe it as postmarketing reports and do not provide a rate, so we cannot quote one.
• “Semaglutide is bad for people with kidney disease.” In FLOW, semaglutide reduced major kidney events in people with type 2 diabetes and chronic kidney disease. That does not remove the dehydration warning.
• “If I feel fine, my kidneys are fine.” Early kidney problems may not cause obvious symptoms; the labels’ monitoring advice is based on tests.
• “Drinking more water means I can ignore persistent vomiting.” If you cannot keep fluids down, the labels’ concern about volume depletion applies. Call your prescriber.

Finding a provider that covers monitoring and follow-up

Dehydration and kidney risk are easier to manage when someone is checking in with you. When comparing services, look at how follow-up is handled in our online GLP-1 telehealth comparison and our clinical quality showdown. If cost or coverage affects whether you can stay on treatment, see GLP-1 providers that accept insurance, oral GLP-1 insurance coverage, and provider-specific write-ups like PlushCare vs. Ro on insurance coverage and Found vs. Hims & Hers. The full list is in our GLP-1 provider directory. Our provider pages are editorial resources, not recommendations; see our advertiser disclosure and editorial standards for how they are produced.

Questions people ask

Medical disclaimer. This article is informational and is not medical advice. If you cannot keep fluids down, or you have little or no urination, fainting, confusion or a rapid heartbeat, seek urgent medical care. Do not start, stop or change a prescribed medicine without instructions from your prescriber.

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