What the product information reports
The Wegovy® label has a short paragraph on urolithiasis, the medical term for stones anywhere in the urinary tract, based on its cardiovascular outcomes trial in more than 17,000 adults followed for about three years [1]. The Canadian Trulicity® monograph includes nephrolithiasis, stones in the kidney, in its table of events reported in more than 1% of people [2]. We did not find stones listed in the US Zepbound® label or the EU Wegovy® product information [3][4].
- These differences are small in absolute terms: in the Wegovy® trial, about four more people per thousand reported a stone over roughly three years [1].
- The labels do not say whether the stones were linked to dehydration, weight loss or something else.
| Document and trial pool | Medicine | Comparison |
|---|---|---|
| Wegovy®, US label, cardiovascular outcomes trial: all reports [1] | 1.2% | Placebo 0.8% |
| Wegovy®, same trial: serious reports [1] | 0.6% | Placebo 0.4% |
| Trulicity®, Canadian monograph, placebo-controlled pool, 26 weeks [2] | 1.0% (0.75 mg), 1.2% (1.5 mg) | Placebo 0.7% |
| Trulicity®, Canadian monograph, all trials up to 104 weeks [2] | 0.8% (0.75 mg), 1.0% (1.5 mg) | Other diabetes medicines 0.7% |
| Zepbound®, US label; Wegovy®, EU product information [3][4] | Not listed | — |
What larger studies show
A US Veterans Affairs study of people with diabetes compared more than 215,000 who started a GLP-1 medicine with over a million who stayed on usual care, across 175 outcomes. Nephrolithiasis was among the outcomes with a higher risk in the GLP-1 group [5]. Observational studies can be skewed by differences in who receives which medicine.
A Canadian study emulating a clinical trial followed about 20,000 people with type 2 diabetes who had already had stones. Recurrences were less common among those who started an SGLT-2 inhibitor than among those who started a GLP-1 medicine, with roughly 105 versus 156 events per thousand person-years [6]. The study was designed to test SGLT-2 inhibitors, so it tells us that GLP-1 medicines did not share that protective association, not that they caused stones.
Urine tests give a different angle. In a Medicare cohort of people with stones, GLP-1 medicines were not linked to any change in 24-hour urine measures that affect stone formation [7]. In 44 stone formers who lost weight on GLP-1 based medicines, urine oxalate fell and none of the stone-risk measures worsened; the authors contrasted this with some other ways of losing weight [8]. Both studies were small and observational.
How a stone could form while on treatment
- Supported by the labels: vomiting, diarrhea and nausea can cause fluid loss, and the labels link that to kidney injury [1][3]. Low urine output is the biggest single risk factor for stones [9].
- Supported by the labels: eating less and feeling full sooner can mean drinking less without noticing, which reduces urine volume.
- Proposed but not measured: changes in diet during weight loss, such as more animal protein, can raise stone risk in people prone to them [11]. No study has linked a specific GLP-1 diet pattern to stones.
- General: obesity, gout, digestive problems, earlier stones and a family history all increase the risk, regardless of medicine [10].
Symptoms of a kidney stone
A stone may cause no symptoms until it moves into the tube that drains the kidney. Then it can cause severe pain that comes and goes in the back, side, lower belly or groin, along with nausea or vomiting [9][12]. Other signs include pink, red or brown urine, a constant need to pass urine, pain on urination, passing only small amounts, cloudy or bad-smelling urine, fever and chills [12].
Some of these overlap with GLP-1 side effects such as nausea and stomach pain, and with the warning signs for gallbladder disease or pancreatitis that the labels describe. Pain in the side or back that comes in waves, with changes in urine, points more towards a stone, but it needs a clinician to tell the difference.
What may help lower the risk
NIDDK calls drinking enough liquid, mainly water, the most important step for preventing stones, and suggests asking a health professional how much is right for you, especially with kidney disease [11]. That fits with the GLP-1 labels, which ask patients to take care to avoid fluid loss during stomach side effects [1][3].
For people who have had a stone, NIDDK explains that diet advice depends on the stone type and may involve sodium, animal protein, calcium and oxalate [11]. Because many people on GLP-1 medicines are encouraged to eat more protein, anyone with a history of stones should ask their clinician or a dietitian how to balance the two.
Do not stop your GLP-1 medicine because of a stone without speaking to your prescriber. If you also take an SGLT-2 inhibitor, gout medicines or diuretics, mention them, since they can affect stone risk [6][10].
Wegovy® is a registered trademark of Novo Nordisk A/S. Zepbound® and Trulicity® are registered trademarks of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Novo Nordisk or Eli Lilly and Company.
When to get help
| Sign | Who to contact | How fast | Source |
|---|---|---|---|
| Severe side or back pain with fever, chills or vomiting | Emergency care or urgent same-day assessment | Emergency | MedlinePlus [9]; NIDDK [12] |
| Being unable to pass urine, or passing only a little | Emergency care | Emergency | NIDDK [12] |
| Sharp pain in the back, side, lower belly or groin, or blood in the urine | A clinician right away | Today | NIDDK [10][12] |
| Ongoing vomiting or diarrhea with little fluid kept down | Your prescriber | Today | Wegovy® and Zepbound® labels [1][3] |
| A past stone, and questions about diet or fluids on a GLP-1 | Your prescriber or a dietitian | At your next appointment | NIDDK [11] |
