Wegovy Side Effects: What to Expect
Adverse reactions reported for semaglutide in its pivotal trial program, plus the boxed warning and serious warnings from the FDA label.
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Most Common Wegovy Side Effects
Adverse reactions reported in the Wegovy FDA label, with the incidence among semaglutide-treated patients and placebo for comparison. Figures are transcribed from the label's adverse-reactions section (DailyMed SetID ee06186f-2aa3-4990-a760-757579d8f77b).
| Adverse reaction | Incidence (Wegovy vs placebo) |
|---|---|
| Nausea | 44% (placebo 16%) |
| Diarrhea | 30% (placebo 16%) |
| Vomiting | 24% (placebo 6%) |
| Constipation | 24% (placebo 11%) |
| Abdominal pain | 20% (placebo 10%) |
| Headache | 14% (placebo 10%) |
| Fatigue | 11% (placebo 5%) |
| Dyspepsia | 9% (placebo 3%) |
| Dizziness | 8% (placebo 4%) |
| Abdominal distension | 7% (placebo 5%) |
| Eructation (burping) | 7% (placebo <1%) |
| Hypoglycemia (in patients with type 2 diabetes) | 6% (placebo 2%) |
| Flatulence | 6% (placebo 4%) |
| Gastroenteritis | 6% (placebo 4%) |
| Gastroesophageal reflux disease (GERD) | 5% (placebo 3%) |
| Gastritis | 4% (placebo 1%) |
| Gastroenteritis viral | 4% (placebo 3%) |
| Hair loss | 3% (placebo 1%) |
| Dysesthesia | 2% (placebo 1%) |
Source: Wegovy FDA prescribing information via DailyMed (SetID ee06186f-2aa3-4990-a760-757579d8f77b), Section 6 Adverse Reactions. Last verified 2026-05-31. This is summary information — read the full label and talk to a prescriber.
Boxed Warning — Thyroid C-Cell Tumors
“In rodents, semaglutide causes dose-dependent and treatment-duration-dependent thyroid C-cell tumors at clinically relevant exposures. It is unknown whether WEGOVY causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans, as the human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined. WEGOVY is contraindicated in patients with a personal or family history of MTC or in patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).”
Verbatim from the Wegovy FDA label (DailyMed SetID ee06186f-2aa3-4990-a760-757579d8f77b). The boxed warning is the FDA's most serious warning. Do not start Wegovy without discussing your personal and family medical history with a licensed prescriber.
Serious Warnings & Precautions
Beyond the common reactions above, the Wegovy label lists these serious risks (Section 5 Warnings & Precautions). They are less common but can be medically urgent — know the symptoms and when to seek care.
- Risk of thyroid C-cell tumors
- Acute pancreatitis
- Acute gallbladder disease
- Hypoglycemia
- Acute kidney injury due to volume depletion
- Severe gastrointestinal adverse reactions
- Hypersensitivity reactions
- Diabetic retinopathy complications in patients with type 2 diabetes
- Heart rate increase
- Pulmonary aspiration during general anesthesia or deep sedation
Compare every Wegovy provider
A prescriber screens for the warnings above before prescribing. See current pricing, verification status, form, and states served across every vetted provider in one place.
Related deep-dives
For management steps and the underlying evidence on each symptom, read our dedicated articles:
- Wegovy constipation: causes & relief →
- Wegovy acid reflux & GERD →
- Wegovy dizziness: causes & management →
- Wegovy fatigue: causes & management →
- Wegovy hair loss & telogen effluvium →
- Wegovy migraines & headaches →
- Wegovy heart palpitations / rate increase →
- Wegovy & sleep disturbance →
- Semaglutide & muscle-mass loss →
- Starting Wegovy: what to expect the first month →
- Zepbound vs Wegovy: side-effect comparison →
- GLP-1 side effects: what the trials showed →
- How long do GLP-1 side effects last? →
- GLP-1 side-effect questions answered →