Search cagrilintide side effects and you get a tidy list. Most of that list was generated by trials of CagriSema, where cagrilintide was given together with semaglutide. Gastrointestinal events in those arms ran between 73.5% and 79.6%.
The short answer. Cagrilintide: The reported side effects are overwhelmingly gastrointestinal: nausea, vomiting, constipation, diarrhea, reduced appetite.
- Gastrointestinal events in the cagrilintide plus semaglutide arms of the REDEFINE trials ran between 73.5% and 79.6%.
- Most published safety data describes CagriSema, not cagrilintide on its own.
- Published exposure stops at 26 weeks for monotherapy and 68 weeks for the combination.
Cagrilintide's reported side effects are mostly gut related. Nausea, vomiting and constipation lead every trial summary. Most of the data comes from CagriSema, not cagrilintide alone. Trials ran 26 weeks and 68 weeks. Nothing longer is published. There is no FDA label, so no official warning list.
What are the side effects of cagrilintide?
In the published trials, the side effects are mostly gut side effects. Nausea, vomiting, constipation, diarrhea and reduced appetite turn up in every safety summary. Injection-site reactions appear as well, because the drug is given under the skin once a week.
The first large human safety readout was Lau and colleagues in The Lancet in 2021. It was a 26-week phase 2 dose-finding trial. It had a placebo arm and an active comparator arm using liraglutide. The weight figure people quote from it is 9.7%. The tolerability figure was gastrointestinal.
The most frequently reported adverse events were gastrointestinal, and most were mild to moderate in severity.
Lau et al., The Lancet, 2021- Nausea. The single most reported event across cagrilintide trials.
- Vomiting. Reported alongside nausea in both the monotherapy and combination programs.
- Constipation and diarrhea. Both directions show up in the same safety tables.
- Reduced appetite. Counted as an adverse event, even though it overlaps with how the drug works.
- Injection-site reactions. Expected with a weekly subcutaneous product.
Across the two REDEFINE trials published in the New England Journal of Medicine in 2025, gastrointestinal adverse events in the cagrilintide plus semaglutide arms ran between 73.5% and 79.6%. That is most participants, not a minority.
Most of the safety data is CagriSema, not cagrilintide alone
This is the part that gets flattened. The big trials did not test cagrilintide by itself. They tested it paired with semaglutide, as CagriSema.
REDEFINE 1, reported by Garvey and colleagues, ran 68 weeks and produced the famous 20.4% weight figure. Its cagrilintide-only arm came in near 11%. REDEFINE 2, reported by Davies and colleagues, studied the combination in adults who also had type 2 diabetes.
| Trial | Who was studied | Length | What the safety section describes |
|---|---|---|---|
| Phase 2 dose-finding (Lancet, 2021) | Adults with overweight or obesity | 26 weeks | Cagrilintide alone, plus liraglutide comparator |
| REDEFINE 1 (NEJM, 2025) | Adults with overweight or obesity | 68 weeks | Mostly cagrilintide with semaglutide |
| REDEFINE 2 (NEJM, 2025) | Adults with overweight or obesity and type 2 diabetes | 68 weeks | Cagrilintide with semaglutide |
So when a page lists cagrilintide side effects, ask which drug produced them. Semaglutide has its own well-known gut profile. Untangling the two from a combination arm is not something a summary can do for you. The split between the compounds is set out in the cagrilintide before and after page.
How long the safety record actually runs
Twenty-six weeks for the monotherapy trial. Sixty-eight weeks for the REDEFINE program. That is the published exposure window.
Published follow-up beyond that is zero. There is no multi-year safety dataset for cagrilintide in either form, because the trials have not run that long. Weight-management drugs are used for years. The safety record here is measured in months.
Trial length also caps what can be seen. Rare events need large numbers of people followed for a long time. A 68-week program can miss an event that shows up once in several thousand patient-years.
A 2024 review of the obesity pipeline in the International Journal of Obesity placed amylin analogs among the most watched agents in development, and flagged the same gap: long-term safety for these newer agents is not yet available.
Cagrilintide, alone and in combination with semaglutide, showed good weight-loss efficacy with a tolerable safety profile; longer-term safety data are awaited.
Dutta et al., Indian Journal of Endocrinology and Metabolism, 2024What the safety record does not contain
Cagrilintide is not FDA-approved, alone or as CagriSema, as of May 2026. That absence is not a footnote. It is the reason several normal safety documents do not exist for this compound.
- No approved label. No official warnings section, no boxed warning, no contraindication list.
- No drug interaction section. Nothing written by a regulator on what it should not be combined with.
- No pregnancy or breastfeeding guidance. Trials of this kind exclude those groups.
- No post-marketing surveillance. Rare events are usually caught after approval, by reporting systems. There is no such stream here.
- No pediatric or older-adult data that we can point you to from these publications.
- Nothing on research-grade material. The published safety record describes pharmaceutical drug product made for trials.
One more checkable item: the World Anti-Doping Agency's 2026 Prohibited List does not name cagrilintide. That is a regulatory fact about sport, not a statement about safety, and the list is revised every year.
More background on what is and is not established sits in the cagrilintide complete guide.
The research vial is not the trial drug
Every percentage on this page came from a manufactured, characterized product given in a monitored trial. A vial sold for research is a different object.
No published study has measured side effects from research-grade cagrilintide. Not one. Any adverse event tied to such a vial could come from the peptide, from an impurity, from residual solvent, from endotoxin, or from something that is not cagrilintide at all.
That is why the paperwork matters more here than the side effect list does. A third-party certificate of analysis from an ISO/IEC 17025 accredited lab is the only thing that connects the label to the contents. How to read a certificate of analysis covers what a real one shows and what a screenshot does not.
Handling adds its own variables. Storage temperature, the water used for reconstitution, and time after reconstitution all change what is in the vial. See peptide storage temperature and the bacteriostatic water guide.
What you can verify before you buy
You cannot verify a safety profile. You can verify documents. These are the things that have an answer you can open and read.
- A batch-matched COA. The batch number on the vial should appear on the document.
- The testing lab. Named, independent, and accredited to ISO/IEC 17025.
- Purity method. HPLC for purity, mass spectrometry for identity. Both, not one.
- Legal status where you are. Covered in are peptides legal.
And keep the two numbers separate in your head. The 20.4% belongs to a combination product studied for 68 weeks. The 9.7% belongs to cagrilintide alone over 26 weeks. Marketing pages mix them, as the cagrilintide benefits page shows.
What to know now
- The reported side effects are overwhelmingly gastrointestinal: nausea, vomiting, constipation, diarrhea, reduced appetite.
- Gastrointestinal events in the cagrilintide plus semaglutide arms of the REDEFINE trials ran between 73.5% and 79.6%.
- Most published safety data describes CagriSema, not cagrilintide on its own.
- Published exposure stops at 26 weeks for monotherapy and 68 weeks for the combination.
- No FDA label exists, so there is no official warnings, contraindication or interaction section.
- No study has ever measured side effects from research-grade cagrilintide vials.
What we're watching
CagriSema REDEFINE 1 trial results explained
Frequently asked questions
Is nausea from cagrilintide the same as nausea from semaglutide?
They look similar in the safety tables, and that is part of the problem. The REDEFINE trials gave the two drugs together, so the combination arms cannot separate them. The cleanest cagrilintide-only safety readout is still the 26-week phase 2 trial in The Lancet, where gastrointestinal events were the most frequent category and were described as mostly mild to moderate.
Does cagrilintide cause low blood sugar?
We cannot source a hypoglycemia rate for cagrilintide from the publications used on this page, so we are not going to state one. The place that question gets answered is Davies and colleagues in the New England Journal of Medicine in 2025, which studied the combination in adults with type 2 diabetes. Without an approved label, there is no regulator-written warning section to check against.
How long do cagrilintide side effects last?
The trial summaries describe gastrointestinal events as mostly mild to moderate, but duration per person is not something the published abstracts report in a way we can quote. What is on record is the length of the trials themselves: 26 weeks for the monotherapy study and 68 weeks for the REDEFINE program. Nothing longer has been published.
Is cagrilintide FDA approved?
No. Neither cagrilintide alone nor CagriSema is FDA-approved as of May 2026. Novo Nordisk is expected to file. An approval for a pharmaceutical would apply to that product, not to a vial sold for research use.
Are there side effects unique to research-grade cagrilintide?
Nobody knows, because nobody has studied it. Zero published trials have used research-grade material. Risks specific to that supply chain are about identity and purity rather than pharmacology: wrong peptide, low purity, residual solvents, endotoxin. A batch-matched certificate of analysis from an ISO/IEC 17025 accredited lab is the only check available.
Is cagrilintide banned in sport?
The World Anti-Doping Agency's 2026 Prohibited List does not name cagrilintide. The list is republished each year and categories can be interpreted broadly, so athletes under testing should read the current version themselves rather than rely on a summary.
References
- Lau, D. C. W., Erichsen, L., Francisco, A. M., Satylganova, A., le Roux, C. W., McGowan, B., Pedersen, S. D., Pietiläinen, K. H., Rubino, D., & Batterham, R. L. (2021). Once-weekly cagrilintide for weight management in people with overweight and obesity: a multicentre, randomised, double-blind, placebo-controlled and active-controlled, dose-finding phase 2 trial. The Lancet, 398(10317), 2160–2172. https://doi.org/10.1016/S0140-6736(21)01751-7
- Garvey, W. T., Blüher, M., Osorto Contreras, C. K., et al. (2025). Coadministered cagrilintide and semaglutide in adults with overweight or obesity. New England Journal of Medicine, 393(7), 635–647. https://doi.org/10.1056/NEJMoa2502081
- Davies, M. J., Bajaj, H. S., Broholm, C., et al. (2025). Cagrilintide–semaglutide in adults with overweight or obesity and type 2 diabetes. New England Journal of Medicine, 393(7), 648–659. https://doi.org/10.1056/NEJMoa2502082
- Dutta, D., Nagendra, L., Harish, B. G., et al. (2024). Efficacy and safety of cagrilintide alone and in combination with semaglutide (CagriSema) as anti-obesity medications: A systematic review and meta-analysis. Indian Journal of Endocrinology and Metabolism, 28(5), 436–444. https://doi.org/10.4103/ijem.ijem_45_24
- Melson, E., Ashraf, U., Papamargaritis, D., & Davies, M. J. (2024). What is the pipeline for future medications for obesity? International Journal of Obesity, 49(3), 433–451. https://doi.org/10.1038/s41366-024-01473-y
- International Organization for Standardization. (2017). ISO/IEC 17025:2017 — General requirements for the competence of testing and calibration laboratories. https://www.iso.org/standard/66912.html
- World Anti-Doping Agency. The Prohibited List 2026. https://www.wada-ama.org/en/prohibited-list