Keep in mind
Stomach trouble is common
In weight trials of semaglutide (Wegovy), nausea affected 44% of people on the shot and 16% on the dummy shot.
Nausea means feeling sick to the stomach; loose stools, vomiting, and constipation were also common.
A dummy shot has no active medicine. Those trial figures describe groups of people, rather than what will happen to you.
Beyond the name you found
Understand serious risks and health-history limits
Severe vomiting or loose stools can lead to fluid loss and kidney injury, as described in the Wegovy label.
The label does not recommend Wegovy for severe gastroparesis, which means the stomach empties very slowly.
The Wegovy label warns about inflammation of the pancreas, an organ involved in digestion. Warning signs include severe belly pain or belly pain that lasts. The pain may also spread toward the back.
The label tells prescribers to stop Wegovy if they suspect this problem.
Before treatment, ask: “If I get severe belly pain that lasts or spreads to my back, do I call you or get urgent care? How do I get help if I cannot reach you?” Write the answer on your help plan.
Emergency care is the step MedlinePlus advises for signs of a severe allergic reaction, including a swollen tongue or difficulty breathing.
The US National Library of Medicine publishes a health guide called MedlinePlus. Bring the help plan into the visit, before a problem arises.
Keep in mind
Ask for a clear help plan
Which symptoms need a quick reply, which need urgent care, and how do I reach the right person?
Write down the health professional’s answer. Ask what happens when the usual contact is unavailable.
Beyond the name you found
Discuss the label’s health-history limits
Reviewing medicines is the US role of the Food and Drug Administration, abbreviated FDA.
Semaglutide labels checked in September 2026 had a boxed warning, the FDA’s strongest warning format, about thyroid tumors seen in rats and mice.
For humans, the labels leave a question unanswered: can semaglutide cause these tumors?
The label rules it out when the patient or their family has a history of medullary thyroid cancer, a rare type.
MEN 2, a rare inherited illness, also rules it out, as does a history of a serious allergic reaction to any ingredient, including semaglutide itself.
Pregnancy plans, eye damage from diabetes, and planned surgery are also label topics for a prescriber to review.
Ask how your own history changes the choice.
Endnotes
Notes for this chapter
- Semaglutide (Wegovy): unwanted effects and history limits
The trial rates and health-history statements come from this label.
- Semaglutide (Ozempic): boxed label notice
The thyroid notice also appears on this product’s label.
- MedlinePlus: severe allergic reactions
This source describes symptoms that call for emergency care.