GLP-1 pill side effects
You are dealing with a symptom and want to know if it is expected.
Reference and calculator, not medical advice. Dosing figures below are transcribed from FDA-approved prescribing information and link back to it. Last reviewed August 2026.
One item on the list below does not apply to a tablet at all: injection site reactions are specific to injectable products. The rest is a class effect and is not route-specific — the gastrointestinal category is the most frequently listed one for oral and injectable products alike, because it follows from how the drug works rather than from how it is delivered.
Listed in the prescribing information
Common adverse reactions listed for GLP-1 receptor agonists as a class.
- NauseaMost commonly reported; typically worst after a dose increase.
- DiarrhoeaGastrointestinal effects are the most frequently listed category.
- VomitingReported more often at higher doses.
- ConstipationRelated to slowed gastric emptying.
- Abdominal painListed across the class.
- Injection site reactionsApplies to injectable products only.
- FatigueListed in product labelling.
- HeadacheListed in product labelling.
These products carry a boxed warning regarding thyroid C-cell tumours observed in rodent studies, and are contraindicated in people with a personal or family history of medullary thyroid carcinoma or MEN 2. Read the full prescribing information for your specific product and discuss it with your prescriber — this summary is not complete and is not a substitute for that document.
Oral semaglutide also carries administration conditions that the injectables do not — how it is taken, with how much water, and how long before anything else. Those sit in their own section of its labelling rather than in adverse reactions, which means they are easy to miss when comparing a tablet against an injection on a side effect list alone.
Sources and last review
Every dosing figure on this page is transcribed from an FDA-approved label and links back to it. Conversions are arithmetic you can repeat by hand. Nothing here is reviewed by a clinician, and this site does not employ one — which is exactly why what I do publish stays traceable to its source.
- Zepbound (Tirzepatide) prescribing information — Eli Lilly, label revised 6 May 2026, checked 7 August 2026
- Mounjaro (Tirzepatide) prescribing information — Eli Lilly, label revised 6 May 2026, checked 7 August 2026
- Wegovy (Semaglutide) prescribing information — Novo Nordisk, label revised 30 June 2026, checked 7 August 2026
- Ozempic (Semaglutide) prescribing information — Novo Nordisk, label revised 10 June 2026, checked 7 August 2026
- Rybelsus (Semaglutide) prescribing information — Novo Nordisk, label revised 20 May 2026, checked 7 August 2026
- Saxenda (Liraglutide) prescribing information — Novo Nordisk, label revised 15 June 2026, checked 7 August 2026
- Trulicity (Dulaglutide) prescribing information — Eli Lilly, label revised 25 March 2026, checked 7 August 2026
Transcribed from the labels above and checked by me — Gavin, who builds this site, takes a GLP-1, and is not a clinician. Last reviewed August 2026. Found an error? [email protected] — I treat corrections as bugs. How this site is built and funded.
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