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The label sheet

GLP-1 Side Effects: What the Four Labels Say

Side effects, serious warnings, and the surgery, pill and pregnancy lines from the US labels of Ozempic, Wegovy, Mounjaro and Zepbound, side by side.

  1. 1Nausea tops all four side-effect tables; people on placebo reported it far less.1,2,3,4
  2. 2All four share nearly the same serious warnings, including rare cases of stomach contents reaching the lungs under anesthesia.1,2,3,4
  3. 3Only Mounjaro and Zepbound warn that the birth control pill may work less well.1,2,3,4
Read the short answer

The short answer

Ozempic and Wegovy are the same drug, semaglutide. Mounjaro and Zepbound share another, tirzepatide.1,2,3,4 Each US label counts side effects in its own trials. Stomach trouble leads all four lists, and nausea comes first. People on placebo, a dummy shot, reported it far less.1,2,3,4 One catch: Ozempic's and Mounjaro's numbers come from diabetes trials, Wegovy's and Zepbound's from weight-loss trials.1,2,3,4 So compare each drug only with its own placebo.

Out of 100 people in each label's trials, how many reported each side effect. Placebo in brackets.1,2,3,4
Trials
Ozempic
Diabetes
Wegovy
Weight loss
Mounjaro
Diabetes
Zepbound
Weight loss
Nausea
Ozempic
16 to 20 (6)
Wegovy
44 (16)
Mounjaro
12 to 18 (4)
Zepbound
25 to 29 (8)
Diarrhea
Ozempic
9 (2)
Wegovy
30 (16)
Mounjaro
12 to 17 (9)
Zepbound
19 to 23 (8)
Vomiting
Ozempic
5 to 9 (2)
Wegovy
24 (6)
Mounjaro
5 to 9 (2)
Zepbound
8 to 13 (2)
Constipation
Ozempic
3 to 5 (2)
Wegovy
24 (11)
Mounjaro
6 to 7 (1)
Zepbound
11 to 17 (5)
Belly pain
Ozempic
6 to 7 (5)
Wegovy
20 (10)
Mounjaro
5 to 6 (4)
Zepbound
9 to 10 (5)

From each label's section 6.1. A range spans the label's drug groups. The trials differ in people and length, so compare each number only with its own placebo figure. Ozempic's decimals are rounded.

The surgery warning on all four labels
All four drugs slow how fast the stomach empties. The labels report rare cases of stomach contents getting into the lungs under anesthesia or deep sedation. The people's stomachs were not empty, though they said they had fasted as told.1,2,3,4 The labels say patients should tell their healthcare providers before any planned surgery or procedure.1,2,3,4 What they cannot say: whether changing the fasting rules or briefly stopping the drug would help. In their words, "Available data are insufficient to inform recommendations".1,2,3,4

The full PDF, free.

  • The common side effects from all four labels next to placebo, how many people stopped over them, and what Wegovy's highest strength adds.
  • A warnings table: what all four share, what only one carries, and what was removed in 2026.
  • Surgery, other pills, the birth control pill, pregnancy and breastfeeding, label by label.
  • The eye risk Europe lists for semaglutide that the US labels do not mention.

A source on every line. No paid placements. No doses.

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The fair line
These rates count what people reported while on the drug or a placebo in each label's own trials. They do not prove the drug caused each event, and the four labels come from different trials.

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