Ozempic (semaglutide) can cause side effects, like many medicines. Most people have mild, temporary effects, especially early on or when the dose is increased. Serious side effects are rare but important to know about.
Common, usually mild side effects (often improve with time or dose adjustments)
- Nausea
- Vomiting
- Diarrhea
- Constipation
- Abdominal pain or indigestion
- Decreased appetite and weight loss
- Injection-site reactions (redness, itching, swelling)
- Headache
- Fatigue or dizziness
Note: GI side effects often occur at the start or with dose increases and tend to lessen over time.
Less common but important side effects
- Hypoglycemia (low blood sugar), especially if used with insulin or sulfonylureas. Signs include sweating, shakiness, confusion, dizziness. Seek help if these occur.
- Pancreatitis (inflammation of the pancreas): severe, persistent upper abdominal pain that may radiate to the back, sometimes with vomiting. Seek medical care urgently.
- Gallbladder disease (gallstones or cholecystitis): sudden severe abdominal pain on the right side, sometimes with fever or jaundice.
- Kidney problems, especially with dehydration from GI side effects.
- Severe allergic reactions: rash, swelling of face/lips/tongue, trouble breathing. Seek emergency care if these occur.
- Thyroid C‑cell tumors in animal studies; humans are not proven to have a higher risk, but there is a boxed warning about medullary thyroid carcinoma. Do not use if you have a personal or family history of MTC or MEN 2.
- Possible, though less common, dizziness or headache.
Important safety notes
- Ozempic slows gastric emptying, which can affect how other oral medicines are absorbed. Some tablets may need to be taken at least 1 hour before or 11 hours after Ozempic. Check with your doctor/pharmacist about your other meds.
- Pregnancy: not established as safe; use effective contraception. If you become pregnant, tell your clinician.
- If you’re using other diabetes medicines (like insulin or sulfonylureas), your doctor may adjust those to reduce the risk of hypoglycemia.
If you’re starting Ozempic or already on it and notice any of the serious symptoms above, or if you have questions tailored to your meds or health, talk with your healthcare provider. Do you want details on a particular side effect or how Ozempic might interact with meds you’re taking?