Free Tool · FDA Data
GLP-1 Side Effect Comparison
Compare reported side effects of Ozempic, Wegovy, Mounjaro, and Zepbound using real data from the FDA Adverse Event Reporting System.
What are the most common side effects of GLP-1 medications?
Quick Answer
The most commonly reported side effects across all GLP-1 medications are gastrointestinal: nausea, vomiting, diarrhea, and constipation. Other frequently reported effects include fatigue, headache, decreased appetite, and injection site reactions. Report frequency varies by medication.
Which GLP-1 medication do you want to learn about?
Select a medication below to see its full side effect profile, or compare them side by side.
Ozempic
semaglutide · Novo Nordisk
59,880 total FAERS reports
Top Reported Side Effects
Wegovy
semaglutide · Novo Nordisk
17,958 total FAERS reports
Top Reported Side Effects
Mounjaro
tirzepatide · Eli Lilly
79,973 total FAERS reports
Top Reported Side Effects
Zepbound
tirzepatide · Eli Lilly
43,290 total FAERS reports
Top Reported Side Effects
How does this tool work?
This tool pulls data directly from the FDA Adverse Event Reporting System (FAERS), a public database maintained by the U.S. Food and Drug Administration. Healthcare providers and patients voluntarily report side effects they experience while taking medications. We present this data as-is — we do not interpret, editorialize, or rank the severity of side effects.
What do these report counts actually mean?
Each count represents the number of times that side effect has been reported to the FDA for that specific medication. Important things to understand:
- Reporting is voluntary. Not every side effect is reported. The actual number of people experiencing a side effect is likely higher.
- Reports do not prove causation. A reported event means someone experienced it while taking the drug — it does not mean the drug caused it.
- Older drugs have more reports. Ozempic (approved 2017) has had more time to accumulate reports than Zepbound (approved 2023).
- Media attention affects reporting. Widely publicized side effects get reported more often, regardless of actual incidence.
Why protein matters for GLP-1 side effects
Many GLP-1 side effects — muscle weakness, fatigue, hair loss — are connected to inadequate nutrition during rapid weight loss. Getting enough protein (0.7–1.0g per pound of body weight) can help preserve muscle mass, support hair growth, and maintain energy levels. Calculate your protein needs →
Frequently Asked Questions
Important: This data comes from the FDA Adverse Event Reporting System (FAERS), a voluntary reporting system. Report counts do not prove the medication caused the event. Not all adverse events are reported, and reporting rates vary by drug, time since approval, and media attention. This tool is for educational purposes only and is not medical advice. Always consult your healthcare provider about medication side effects.