Cagrilintide: What the Evidence Shows, and Why You Can't Buy It

Cagrilintide is an experimental once-weekly injection from Novo Nordisk that copies amylin, a fullness hormone the pancreas releases alongside insulin. It does work on its own: in the largest trial so far, people taking only cagrilintide lost 11.8% of their body weight over 68 weeks if they stayed on it, against 2.3% on placebo.^[2] That is real weight loss, but less than semaglutide produced in the same trial. Cagrilintide is not approved anywhere, either alone or inside CagriSema, its combination with semaglutide. FDA says it cannot be used in compounding,^[12] so there is no legal way to buy it. Our FDA warning-letter tracker holds 5 letters to companies that sold or supplied it.

What cagrilintide is

Amylin is a hormone made by the same pancreatic cells that make insulin, and it helps you feel full after eating.^[1] The body’s own amylin is hard to turn into a drug because it tends to clump into fibrils. One older amylin drug, pramlintide, is sold for diabetes, but it wears off quickly and has to be injected three times a day.^[6]

Cagrilintide is Novo Nordisk’s answer to that problem: a stabilized amylin analog with a fatty-acid chain attached so it lasts long enough for one shot a week.^[6] Novo describes it as working “differently than currently approved GLP-1-based treatments for weight loss.”^[3] In mice, its weight-lowering effect depended on two specific amylin receptors in the brain,^[7] which is consistent with the idea that it acts on appetite through a different route from semaglutide or tirzepatide. That difference is the whole reason Novo pairs the two drugs.

It is a separate approach from amycretin, which builds the GLP-1 and amylin actions into one molecule instead of combining two drugs. That trial is covered in amycretin: what the phase 1b showed.

Does cagrilintide work on its own?

Yes, but it is not as strong as semaglutide. The three randomized trials below report weight results for a cagrilintide-only group, and each found meaningful weight loss.

The first trial established the dose range. Every dose beat placebo, and the highest, 4.5 mg, edged out daily liraglutide by 1.8 percentage points at 26 weeks.^[1] The diabetes trial was small, but it showed cagrilintide lowering blood sugar far less than semaglutide (0.9 points of HbA1c against 1.8), even though it lowered weight a little more over that short period.^[4]

REDEFINE 1 is the one that matters most. It was built to test CagriSema, but it also randomized 302 people to cagrilintide 2.4 mg alone for 68 weeks. Counting everyone randomized, they lost 11.5% of their weight; if everyone had stayed on treatment, 11.8%. Semaglutide alone produced 14.9% and 16.1% on the same two measures.^[2] Novo reports that about one in three people on cagrilintide (31.6%) lost at least 15% of their weight, against about one in twenty on placebo.^[3] Few people on cagrilintide reached the very large losses: 6.5% lost a quarter of their weight or more, against 14.8% on semaglutide.^[2]

Put simply, cagrilintide alone sits roughly where the earlier generation of weight-loss drugs sits, well short of semaglutide or tirzepatide. Its case rests on what it adds in combination, and on how it feels to take.

Side effects: the part that looks different

Like GLP-1 drugs, cagrilintide mainly causes stomach and gut side effects, plus injection-site reactions.^[1] The difference is how often. In REDEFINE 1, gastrointestinal side effects were reported by 54.0% of people on cagrilintide, against 73.8% on semaglutide and 39.9% on placebo.^[2]

Fewer gut side effects and fewer people quitting over them is the strongest argument for cagrilintide alone. Novo reports that nausea made 1.0% of people on cagrilintide stop permanently, against 0.1% on placebo.^[3] Serious adverse events were somewhat more common than on semaglutide. The trial was built to test CagriSema against placebo, not to compare the two single-drug groups, which held about 300 people each, so that gap should be read with care. In the 2023 diabetes trial, 80% of the cagrilintide group reported some adverse event, against 71% on semaglutide, in groups of about 30 people.^[4] In REIMAGINE 2, 82.2% of the cagrilintide group reported one, against 70.5% on placebo.^[5]

Is Novo developing cagrilintide by itself?

Yes. After the REDEFINE 1 results, Novo said it would move cagrilintide into its own phase 3 program, called RENEW.^[3] Two RENEW trials are registered. Both compare once-weekly cagrilintide with placebo for 64 weeks, both started in November 2025, and both have finished enrolling. Results are expected in 2027.

Sources: RENEW 1^[8] and RENEW 2.^[9] Novo’s August 2026 financial report also lists a phase 3 trial of a higher cagrilintide dose as due to start in the fourth quarter of 2026.^[11] Novo has not said when, or whether, it will file cagrilintide alone for approval, so there is no approval date to give.

Is cagrilintide approved? The CagriSema decision

No. Cagrilintide is not approved on its own, and FDA states that it is not a component of any FDA-approved drug.^[12] The first approval it could get is as part of CagriSema. Novo submitted CagriSema to FDA on December 18, 2025, based on REDEFINE 1 and REDEFINE 2, and noted at the time that CagriSema did not yet have approval in either the US or the EU.^[10] Novo’s August 2026 report lists the U.S. decision on CagriSema as expected in the fourth quarter of 2026.^[11]

An approval of CagriSema would not make cagrilintide on its own a legal prescription drug. It would approve one fixed combination product for weight management. How CagriSema compares with what is already on the market is on our CagriSema vs Wegovy page, and the full late-stage field is on the GLP-1 pipeline tracker.

Can you buy cagrilintide?

Not legally. FDA puts it plainly:

Retatrutide and cagrilintide cannot be used in compounding under federal law. Additionally, these are not components of FDA-approved drugs and have not been found safe and effective for any condition.^[12]

— FDA, FDA's concerns with unapproved GLP-1 drugs used for weight loss

With no approved product and no compounding route, there is no lawful source for a patient. Our explainer on what cannot legally be compounded sets out the rules, and are peptides legal? covers the wider peptide market.

It is sold anyway, mostly as a powder in a vial from “research peptide” websites. FDA has rejected that label in its letters. One seller marketed “CAGRILINTIDE” and a cagrilintide–semaglutide blend called “CagriLean” while labeling them “FOR RESEARCH USE ONLY” and “NOT INTENDED FOR HUMAN USE”; FDA found the products were intended as drugs for people.^[13] Another seller’s cagrilintide page borrowed trial-style claims, such as weight loss of 25% or more in 40.4% of patients, while its labels said “laboratory research purposes only.”^[14] Others hide it behind code names: one letter records a “Cag (1mg) Tirz (10mg) Blend,” mixing cagrilintide with tirzepatide.^[16]

The supply chain behind compounders has been reached too. FDA warned an ingredient distributor that had imported and sold cagrilintide; the company told FDA it had stopped importing and distributing it, and FDA accepted that correction.^[15] None of these products went through the trials above. A vial labeled cagrilintide is not the drug Novo tested, and there is no way for a buyer to check what is in it.

The FDA warning letters that name cagrilintide

Our FDA warning-letter tracker holds 5 letters that name cagrilintide, dated December 2024 through March 2026. Several of the same letters also name retatrutide, which is covered in retatrutide: what the evidence shows.

What to do instead

• Use an approved drug. Semaglutide (Wegovy) and tirzepatide (Zepbound) are approved for weight management. In REDEFINE 1, semaglutide alone produced more weight loss than cagrilintide alone.^[2]
• Join a trial if you want cagrilintide itself. Inside a registered study is the only way to take it legally. The RENEW trials have finished enrolling,^[8] but ClinicalTrials.gov lists a few smaller cagrilintide studies that are still recruiting.
• Wait for the CagriSema decision. If FDA approves it, that will be the first legal way to get cagrilintide outside a trial, and only as part of the combination.^[11]