GLP-1 side effects: the full list, and how common each one is
From the FDA labels
Every number here comes from the trials on each drug's FDA label.
By the Peptide Science Desk Editorial TeamFact-checked against FDA and official sources · Not yet reviewed by a licensed clinician. How we check facts
Short answer: The most common GLP-1 side effects are stomach problems: nausea, diarrhea, throwing up and constipation. In the weight-loss trials, 28 to 44 in 100 people on Wegovy, Zepbound or Foundayo felt sick, vs 8 to 16 in 100 on a fake pill or shot. Most people kept taking the drug. Rare but serious problems include pancreatitis and gallbladder disease.
GLP-1 guide: how it works, the full drugs list and side effects
What are the most common GLP-1 side effects?
- Stomach problems are by far the most common: nausea (feeling sick), diarrhea, vomiting (throwing up), constipation and belly pain.
- Other common ones on the Wegovy label: headache, feeling tired, burping and heartburn.
- Zepbound and Foundayo labels list similar stomach side effects.
- See the table below for how often each one happened.
When do GLP-1 side effects happen?
- The Zepbound and Foundayo labels say stomach side effects happened most while the dose was going up.
- That is why doctors start with a low dose and raise it slowly.
- Tell your doctor if side effects do not get better. Do not change your dose on your own.
How do I stop or ease nausea on Ozempic, Wegovy or Zepbound?
- There is no proven cure. The Wegovy maker and a 2022 expert panel suggest simple eating habits that may help. Ask your doctor before changing anything.
- Eat smaller meals, eat slowly, and stop as soon as you feel full.
- Pick bland, low-fat foods, like crackers, toast and rice, and foods with water in them, like soup and gelatin.
- Avoid greasy, fried or spicy food and strong smells.
- Do not lie down right after eating. Going outside for fresh air may help.
- Sip fluids during the day so you do not get dehydrated, but not so much that you feel too full.
- Nausea is most common while the dose goes up. Never change your dose on your own. Your doctor may keep you on a dose longer.
- Get help right away if you cannot keep fluids down, or have bad belly pain that will not go away. It can be a sign of pancreatitis.
How many people stop a GLP-1 because of side effects?
- Most people kept going. In the trials, about 7 in 100 people on Wegovy or Zepbound (15 mg) stopped for good because of side effects, vs about 3 in 100 on placebo.
- On Foundayo (17.2 mg), 10 in 100 stopped, vs 3 in 100 on placebo.
- Stomach problems were the main reason people quit.
- The big trials say the same. In the Zepbound trial, 6.2 in 100 people on the top dose stopped because of side effects, vs 2.6 on placebo.
- In the Wegovy trial, 4.5 in 100 stopped because of stomach problems, vs 0.8 on placebo.
- See the study table below.
What are the serious GLP-1 side effects?
- Pancreatitis: bad belly pain that will not go away, sometimes going to your back, with or without throwing up.
- Gallbladder problems, like gallstones: pain in the upper right belly, fever, yellow skin or eyes.
- Kidney problems: losing a lot of fluid from vomiting or diarrhea can hurt your kidneys. Drink fluids.
- Low blood sugar: mostly when taken with insulin or a sulfonylurea (a type of diabetes pill).
- Serious allergic reactions: swelling of the face, lips or throat, trouble breathing.
- Faster heartbeat: the labels say your doctor should check your heart rate.
- Mood: the Wegovy, Zepbound and Saxenda labels used to warn about thoughts of suicide. That warning was taken off in February 2026. Still, tell your doctor about any mood changes.
- Breathing in food during surgery: tell your surgeon or dentist you take a GLP-1 before any anesthesia.
What is the GLP-1 thyroid cancer warning?
- Wegovy, Ozempic, Mounjaro and Zepbound have a boxed warning. In rats and mice, these drugs caused thyroid tumors, including cancer.
- No one knows if this happens in people.
- Do not take them if you or your family have had medullary thyroid cancer (MTC), or if you have MEN 2.
- Tell your doctor about a lump or swelling in your neck, trouble swallowing, or a hoarse voice that does not go away.
Are compounded GLP-1 side effects different?
- The same drug can cause the same side effects. But compounded semaglutide and tirzepatide are not FDA approved, so the FDA has not checked their strength or quality.
- The FDA has reports of people who got sick from taking too much of a compounded GLP-1, often from measuring mistakes with multi-dose vials.
- Check any compounded vial against FDA recalls with our GLP-1 recall checker (linked below).
- A poison center reported 3 people who took about 10 times too much compounded semaglutide by mistake. They threw up and had belly pain for days.
- A study of FDA reports found compounded GLP-1 shots had more reports of mixing mistakes, germs in the drug, and hospital stays than brand drugs. Reports can show a pattern, not a cause.
How many people felt sick (nausea) on GLP-1 drugs
% of adults with nausea in the weight-loss trials, drug vs placebo (fake medicine)
Wegovy shot (semaglutide 2.4 mg)3 trials · 2,116 adults on the drug · up to 68 weeks
44%
16%
Foundayo pill (orforglipron 17.2 mg)2 trials · 1,049 adults on this dose · not a peptide
35%
10%
Zepbound shot (tirzepatide 15 mg)2 trials · 941 adults on this dose · up to 72 weeks
28%
8%
Different trials, different people: not a head-to-head comparison.
Show the numbers as a table
| Trial | Drug | Placebo |
|---|---|---|
| Wegovy shot (semaglutide 2.4 mg) 3 trials · 2,116 adults on the drug · up to 68 weeks | 44% | 16% |
| Foundayo pill (orforglipron 17.2 mg) 2 trials · 1,049 adults on this dose · not a peptide | 35% | 10% |
| Zepbound shot (tirzepatide 15 mg) 2 trials · 941 adults on this dose · up to 72 weeks | 28% | 8% |
Key studies on GLP-1 side effects
| Study type | People | Main finding | Limits |
|---|---|---|---|
| STEP 1 trial, Wegovy (semaglutide) | 1,961 adults | Nausea and diarrhea were most common. 4.5% stopped for stomach problems vs 0.8% on placebo | 68 weeks long |
| SURMOUNT-1 trial, Zepbound (tirzepatide) | 2,539 adults | Most side effects were stomach problems, mostly while the dose went up. 4.3% to 7.1% stopped vs 2.6% on placebo | 72 weeks long |
| ATTAIN-1 trial, Foundayo (orforglipron) pill | 3,127 adults | 5.3% to 10.3% stopped because of side effects vs 2.7% on placebo | 72 weeks long |
| FDA reports, compounded vs brand GLP-1 | 81,078 reports (707 compounded) | Compounded shots had more reports of mixing errors, contamination and hospital stays | Reports cannot prove cause |
| Poison center cases, compounded semaglutide | 3 people | Dosing mistakes (2 took about 10 times too much) caused days of vomiting and belly pain | Only 3 cases |
GLP-1 side effects on the FDA labels: drug vs placebo
| Side effect | Wegovy shot (2.4 mg) | Zepbound shot (15 mg) | Foundayo pill (17.2 mg) |
|---|---|---|---|
| Nausea | 44% vs 16% | 28% vs 8% | 35% vs 10% |
| Diarrhea | 30% vs 16% | 23% vs 8% | 25% vs 11% |
| Vomiting | 24% vs 6% | 13% vs 2% | 24% vs 4% |
| Constipation | 24% vs 11% | 11% vs 5% | 24% vs 9% |
| Hair loss | 3% vs 1% | 5% vs 1% | 5% vs 2% |
| Stopped for side effects | 6.8% vs 3.2% | 6.7% vs 3.4% | 10% vs 3% |
FAQ
How long do GLP-1 side effects last?
For many people, stomach side effects are worst in the first weeks and when the dose goes up. If they last or are bad, call your doctor.
Does Ozempic have the same side effects as Wegovy?
They have the same drug, semaglutide, so the side effects are much the same. Wegovy is used at higher doses for weight loss.
Which GLP-1 has the fewest side effects?
The trials were different, so we cannot rank them fairly from these labels. Your doctor can help you choose.
Can GLP-1 side effects be dangerous?
Most are mild to moderate. Get help right away for bad belly pain that will not stop, signs of an allergic reaction, or yellow skin or eyes.
Does ginger help with Ozempic nausea?
Maybe. A 2022 expert panel listed crackers, apples, mint and ginger as foods that may ease nausea. We found no trial that tested ginger for GLP-1 nausea.
Is there medicine for Ozempic nausea?
Some doctors prescribe anti-nausea medicine. Ask your doctor; do not start one on your own, and tell them about every drug you take.
Is GLP-1 nausea a sign it is working?
No. Nausea is a side effect, not proof that the drug works.
Related pages
- GLP-1: what it is, drugs list and side effectsGLP-1 guide
- GLP-1: Wegovy / Ozempic (semaglutide)FDA approved · Proof: Strong
- GLP-1: Zepbound / Mounjaro (tirzepatide)FDA approved · Proof: Strong
- GLP-1 pill: Foundayo (orforglipron)FDA approved · Proof: Strong
- GLP-1: Saxenda / Victoza (liraglutide)FDA approved · Proof: Strong
- GLP-1: RetatrutideIn testing · Proof: Strong
- GLP-1 hair loss: how common is it, and does it grow back?Guide
- Peptide side effects: what is common and what is serious?Guide
- Semaglutide vs Tirzepatide: What's the Difference?Guide
- Compounded Semaglutide: Is It Safe?Guide
- Is Zepbound a GLP-1? What GLP-1 really meansGuide
- Peptides before surgery: do you have to stop GLP-1 drugs like Ozempic?Guide
- Can peptides cause blood clots, hair loss, diarrhea and more? Short answersGuide
- Peptides for loose skin after weight loss: does GHK-Cu work?Guide
- Peptide injection site reaction: red, itchy or a lump. When to worryGuide
- Peptide side effects checkerTool
- Peptide drug interaction checkerTool
- GLP-1 recall checkerTool
- GLP-1 pill vs shotTool
- GLP-1 price trackerTool
- Compare GLP-1: Wegovy / Ozempic vs GLP-1: Zepbound / MounjaroComparison tool
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Sources
- DailyMed (FDA label): Wegovy (semaglutide) prescribing information
- DailyMed (FDA label): Zepbound (tirzepatide) prescribing information
- DailyMed (FDA label): Foundayo (orforglipron) prescribing information
- MedlinePlus (NIH): GLP-1 agonists
- Wegovy.com (Novo Nordisk): Wegovy side effects and tips for managing nausea
- PubMed: Gorgojo-Martínez et al., Clinical recommendations to manage gastrointestinal adverse events in patients treated with GLP-1 receptor agonists: a multidisciplinary expert consensus, J Clin Med 2022
- FDA: Concerns with unapproved GLP-1 drugs used for weight loss
- PubMed: Wilding et al., Once-weekly semaglutide in adults with overweight or obesity (STEP 1), NEJM 2021
- PubMed: Jastreboff et al., Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1), NEJM 2022
- PubMed: Wharton et al., Orforglipron, an oral small-molecule GLP-1 drug for obesity (ATTAIN-1), NEJM 2025
- PubMed: McCall et al., Safety analysis of compounded GLP-1 receptor agonists in the FDA adverse event reporting system, Expert Opin Drug Saf 2026
- PubMed: Lambson et al., Administration errors of compounded semaglutide reported to a poison control center, J Am Pharm Assoc 2023