Wegovy® (injection) and kidney stones

Where the 1.2% comes from

SELECT enrolled adults aged 45 or older with established cardiovascular disease and a BMI of 27 or more, but no diabetes. ^[4] On the label, 8,803 people received Wegovy® for a median of 37.3 months and 8,801 received placebo for a median of 38.6 months. ^[1] The urolithiasis paragraph sits in the label’s list of other adverse reactions and is drawn from this trial. ^[1]

Two details shape how to read it. First, the trial did not record every symptom: the label states that safety collection was limited to serious adverse events, events that led to stopping treatment, and adverse events of special interest. ^[1] Second, the absolute difference is small. Over roughly three years, about four more people per thousand reported a stone on Wegovy® than on placebo. ^[1]

Why the weight trials show nothing

The 68-week STEP trials that support Wegovy® for weight reduction were shorter and smaller than SELECT, and the US table only shows reactions reported by at least 2% of people on Wegovy® and more often than on placebo. ^[1] A difference measured in tenths of a percent would not reach that cut-off. The Canadian table uses a 1% threshold and lists rarer reactions separately; stones are in neither list. ^[3] Absence from these tables means no signal large enough to tabulate, not proof of zero risk.

The European summary lists stones nowhere in its frequency table, which pools STEP 1 to 4 and post-marketing reports. ^[2] For the 7.2 mg dose and for adolescents, the US label shows no stone row either. ^[1]

How a stone and Wegovy® might connect

• What the label documents: nausea, vomiting and diarrhea are the most frequent Wegovy® reactions, and section 5.5 describes acute kidney injury, mostly in people who became dehydrated after them. ^[1] In the adult weight trials, acute kidney injury affected 7 people on Wegovy® and 4 on placebo, and occurred more often during dose increases. ^[1]
• What general medicine adds: stones grow when urine carries more crystal-forming minerals than it can hold, and MedlinePlus calls not drinking enough fluid the single biggest risk factor. ^[7]
• What is proposed but unmeasured: eating much less can also mean drinking less, and a change of diet during weight loss can shift the minerals in urine. No Wegovy® study has tested either link.
• What points the other way: in 44 people with a history of stones who lost weight on GLP-1 based medicines over about a year, urine oxalate fell and calcium, uric acid, citrate and total volume did not change significantly. ^[5]

Larger studies, read with care

A 2025 analysis of US veterans with diabetes followed 215,970 people who started a GLP-1 medicine and compared them with usual care across 175 outcomes. Kidney stones were among the risks found to be higher. ^[6] This was an observational study in people with diabetes using several GLP-1 medicines, so it cannot isolate Wegovy® or rule out differences between the groups.

A 2026 systematic review of 84 studies on obesity and the urinary tract described obesity as a risk factor for stones in its own right. It also found that Roux-en-Y gastric bypass raises stone risk two- to fourfold through extra oxalate absorbed from the gut, while sleeve gastrectomy does not. ^[9] That matters for the many people who start Wegovy® after earlier weight-loss surgery.

Other reasons a stone may form

NIDDK lists several conditions that make stones more likely, regardless of medicine ^[8]:

• A previous stone or a family history of stones; men are affected more often than women.
• Not drinking enough liquids.
• Obesity, gout, long-lasting bowel inflammation, other digestive problems and past gastrointestinal surgery.
• Conditions that put extra calcium, oxalate or uric acid into urine, and repeated urinary tract infections.
• Some medicines taken over a long period.

Telling stone pain from other Wegovy® pain

A stone often causes nothing until it moves. Then MedlinePlus describes sudden, severe pain in the side of the back or the belly that comes and goes, may spread to the groin, and can bring blood in the urine, fever, chills, nausea and vomiting. ^[7] NIDDK adds pain while passing urine, a constant urge to go and cloudy or foul-smelling urine. ^[10]

Wegovy® carries two warnings about pain in nearby areas. The Medication Guide describes pancreatitis as severe stomach pain that will not go away and may reach the back, and gallbladder trouble as pain in the upper stomach, sometimes with fever, yellow skin or eyes, or clay-coloured stools. ^[1] The label also reports appendicitis in 0.5% on Wegovy® vs 0.2% on placebo. ^[1] Because these overlap, new severe pain needs a clinician rather than a guess.

Steps general sources describe

For prevention, NIDDK puts drinking enough liquid, mainly water, first and asks people to check the right amount with a health professional, particularly if they have kidney disease. ^[11] After a stone, it explains that diet changes depend on the stone type and may involve sodium, animal protein, calcium and oxalate, and that calcium from food does not cause calcium oxalate stones. ^[11] A dietitian can help balance this with the protein focus many people adopt during weight loss. ^[11]

The Wegovy® label asks patients to take precautions against fluid loss and to report nausea, vomiting or diarrhea that persists. ^[1] On the days those effects are strongest, fluids are easiest to forget.

Wegovy® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk.

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