GLP-1 Side Effects: What Labels List and What Users Report
GLP-1 side effects across semaglutide, tirzepatide, liraglutide and pills: common GI effects, serious label warnings and user reports. Not medical advice.
Anonymous user report. Not medical advice. Peptides discussed are not FDA-approved for the uses described. Editorial process →
Short answer
GLP-1 drugs (semaglutide, tirzepatide, liraglutide, dulaglutide, and pills such as Rybelsus, the Wegovy pill and Foundayo) share a side-effect class. Most common: nausea, vomiting, diarrhoea, constipation, abdominal pain, reduced appetite and fatigue, usually worst when starting or stepping up. Serious label warnings include pancreatitis, gallbladder disease, kidney injury from dehydration, low blood sugar when combined with insulin or sulfonylureas, and a boxed warning on thyroid C-cell tumours seen in rodents for the long-acting injectables. Labels also flag aspiration risk around anaesthesia because stomach emptying slows, and semaglutide labels address diabetic eye changes; In June 2025 the European Medicines Agency's safety committee concluded that NAION, an optic-nerve condition that can cause vision loss, is a very rare side effect of semaglutide (up to 1 in 10,000 people); sudden vision loss needs urgent medical review. Fast weight loss can bring hair shedding and muscle loss. Severe abdominal pain, persistent vomiting or vision changes need prompt care. Peptide Confessions does not publish dosing, timing, injection or sourcing guidance.
Side effects by drug
Rounded rates from pivotal weight-management trials (highest dose vs placebo). Diabetes-strength doses generally have lower rates. Last reviewed October 15, 2026.
| Drug (trial) | Nausea | Diarrhoea | Vomiting | Page |
|---|---|---|---|---|
| Semaglutide / Wegovy (STEP 1) | About 44% vs 17% | About 32% vs 16% | About 25% vs 7% | Wegovy side effects |
| Tirzepatide / Zepbound (SURMOUNT-1) | About 31% vs 10% | About 23% vs 7% | About 12% vs 2% | Zepbound side effects |
| Liraglutide / Saxenda (SCALE) | About 40% vs 15% | About 21% vs 9% | About 16% vs 3% | GLP-1 medications |
Serious but less common risks
Pancreatitis (severe, persistent abdominal pain, sometimes into the back), gallbladder disease (gallstones are more common with rapid weight loss), acute kidney injury from vomiting or diarrhoea, low blood sugar with insulin or sulfonylureas, allergic reactions, and worsening diabetic eye disease after rapid glucose improvement. The boxed warning on long-acting injectables covers thyroid C-cell tumours in rodents. Labels also warn about aspiration risk during anaesthesia, so surgical teams should know you take one. Research on suicidal thoughts and on bowel obstruction is ongoing; tell a prescriber about new mood changes or severe constipation.
Appearance and body changes
Fast weight loss can bring hair shedding (Ozempic hair loss), facial volume loss (Ozempic face) and muscle loss (Ozempic muscle loss). These follow weight loss rather than appearing on labels as named effects.
What users report here
#298 lists "nausea. vomiting. constipation. burping" and says month one was spent "on the bathroom floor earning it." #276 warns about sulfur burps on tirzepatide. #43 lost a third of their hair density in five months. #290 describes a racing heart and an ER visit. Not all surprises are bad: #45 describes a spouse losing interest in alcohol.
Stopping brings its own complaint: appetite returns fast (#87). Reports: semaglutide and tirzepatide. In Canada: GLP-1 side effects in Canada.
Related topics
data reports:
related peptides:
community guides:
More confessions from the archive
Community Q&A
- Which GLP-1 has the fewest side effects?
- Trials aren't directly comparable, but in pivotal weight trials nausea rates were somewhat lower with tirzepatide than semaglutide. Tolerance varies by person and dose.
- When should a GLP-1 side effect be treated as urgent?
- Severe ongoing abdominal pain, signs of dehydration, yellowing skin, allergic swelling or trouble breathing need prompt medical care.
- What is the most common GLP-1 side effect?
- Nausea, followed by other gastrointestinal effects such as diarrhoea, constipation and vomiting.
- Do GLP-1 side effects go away?
- For many people GI effects ease after the first weeks or after a dose change settles, but not for everyone. Persistent or severe symptoms should be discussed with a prescriber.
- Do GLP-1 pills have the same side effects as injections?
- Broadly the same class of effects. Each product label has its own list.
- Does this page give dosing advice?
- Peptide Confessions does not publish dosing, timing, injection or sourcing guidance.
- Who should not take a GLP-1?
- Labels say not to use semaglutide, tirzepatide or similar drugs with a personal or family history of medullary thyroid cancer or MEN2, or a prior serious allergic reaction to the drug. Pancreatitis history, pregnancy plans and certain eye or gut conditions need discussion with a clinician.
- What is the safest GLP-1 to take?
- No single GLP-1 is safest for everyone; side-effect profiles are similar across the class. Liraglutide, semaglutide and dulaglutide have trials showing cardiovascular benefit in high-risk people. The choice is made with a clinician.
Sources
- STEP 1 — Wilding et al., Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med 2021
- SURMOUNT-1 — Jastreboff et al., Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med 2022
- SCALE Obesity — Pi-Sunyer et al., A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management. N Engl J Med 2015
- Zepbound (tirzepatide) prescribing information — DailyMed (NLM)
- Wegovy (semaglutide) prescribing information — DailyMed (NLM)
- Ozempic (semaglutide) prescribing information — DailyMed (NLM)
- Saxenda (liraglutide) prescribing information — DailyMed (NLM)
- EMA PRAC meeting highlights, 2–5 June 2025 (semaglutide and NAION)
Anonymous first-hand reports plus sourced context — educational only, not medical advice. Editorial policy & corrections.