Here are the 12 most common questions about cagrilintide. Each answer notes its evidence base and what remains uncertain.
[1. What is cagrilintide?]
A synthetic long-acting amylin analogue. Amylin is a hormone co-released with insulin after meals that slows gastric emptying and signals satiety. Novo Nordisk developed it for weight management. It is dosed once weekly and is not approved in any country.
[2. What is cagrilintide used for?]
Clinical trials show it reduces body weight. Monotherapy produced 10.8% loss at 26 weeks and 11.5% at 68 weeks. Its main role is as the amylin component of CagriSema, combined with semaglutide, which is under FDA review.
[3. Cagrilintide vs retatrutide: which is stronger?]
Retatrutide is clearly stronger. Retatrutide lost 24.2% at 48 weeks in Phase II; cagrilintide lost 10.8% at 26 weeks and 11.5% at 68 weeks as monotherapy. The two have never been directly compared, and they act on different receptors.
[4. Can cagrilintide be used with retatrutide?]
No human trial has validated it. The only evidence is a September 2026 rat study showing the combination beat either drug alone. Neither drug is approved, neither can be compounded, and the fixed-ratio premixed vials sold online have not been tested.
[5. What is the cagrilintide dose?]
Trials titrated to 2.4 mg weekly. A 4.5 mg dose was tested in Phase II and dropped for higher nausea rates. Community protocols copy semaglutide's titration schedule: 0.25, 0.5, 1.0, 1.7, 2.4 mg at four-week intervals. No verified protocol exists outside trials.
[6. What are the side effects?]
Nausea, constipation, diarrhoea and injection-site reactions. In the Phase II monotherapy trial, 41–63% of participants reported GI adverse events versus 32% on placebo. With semaglutide, around 80% reported GI events. Fatigue may be an amylin class effect, but the evidence is currently insufficient.
[7. What is CagriSema, and is it FDA approved?]
CagriSema is a once-weekly combination of 2.4 mg cagrilintide and 2.4 mg semaglutide. It produced 20.4% weight loss at 68 weeks in REDEFINE 1. Novo Nordisk filed with the FDA on 18 December 2025, with a decision expected in 2026. It is not yet approved.
[8. Can cagrilintide be legally purchased?]
Selling it as a human drug violates US federal law. The FDA issued warning letters to suppliers in March 2026. It cannot be compounded or prescribed. Enforcement targets sellers, but buyers receive an unapproved drug from an unregulated channel.
[9. What is eloralintide, and how is it different?]
Eloralintide is Eli Lilly's amylin agonist, selective for the amylin receptor, whereas cagrilintide also acts on the calcitonin receptor. In Phase II monotherapy it produced up to 20% weight loss at 48 weeks — nearly double cagrilintide monotherapy — and entered Phase III in 2026.
[10. Does CagriSema beat tirzepatide?]
Not in obesity. In REDEFINE 4, CagriSema lost 23.0% at 84 weeks versus 25.5% for tirzepatide 15 mg, failing non-inferiority. In a September 2026 diabetes trial, low-dose (1 mg / 1 mg) CagriSema beat tirzepatide 5 mg on weight loss. Neither result is formally published.
[11. What does the rat study have to do with cagrilintide?]
The September 2026 Nature Metabolism study found cagrilintide plus retatrutide produced greater weight loss in obese rats than either drug alone or equivalent-dose comparators. It is preclinical, dosed daily, and cannot be extrapolated to weekly human dosing. The authors' conclusion points to "next-generation molecule design," not a dosing protocol.
[12. What are the biggest unknowns?]
Three: no human safety data beyond 84 weeks; zero human data for cagrilintide plus retatrutide; and no post-discontinuation weight maintenance data. Additionally, every human trial was funded by Novo Nordisk, so independent replication is lacking.