What cagrilintide is
Amylin is a hormone co-secreted with insulin by the pancreas. It slows gastric emptying, suppresses glucagon after meals and promotes satiety. Cagrilintide is a long-acting synthetic analogue designed to activate amylin receptors with once-weekly dosing.
It is being developed by Novo Nordisk, principally in combination with semaglutide under the name CagriSema. It is investigational and approved nowhere.
The combination is the point
This is the detail that most vendor pages omit. Cagrilintide's late-stage development has focused overwhelmingly on the combination with semaglutide, because amylin and GLP-1 signalling act through partly distinct satiety pathways and appear to add to one another.
Most of what is known about cagrilintide at scale is what it does alongside semaglutide, not what it does alone.
Standalone phase 2 data does exist and supports a genuine independent effect on body weight. But the depth of evidence behind monotherapy is considerably shallower than behind the combination, and the grey market sells it as a standalone vial.
What that means in practice
People buying cagrilintide alone are using it in the configuration with the least late-stage data. People buying it to stack with a separately sourced GLP-1 are reconstructing a combination product without the controlled ratio, the titration schedule, or the safety monitoring that defined the trials.
Combination products are developed as combinations for a reason. The dose relationship between the two components is studied, not assumed. Assembling an approximation from two unregulated vials is not the same intervention, even if the component names match.
Known adverse effects
Gastrointestinal effects — nausea and vomiting in particular — are the dominant adverse events across amylin analogue trials, and are amplified in combination with GLP-1 agonists. This is the expected consequence of two agents both slowing gastric emptying.
Trial protocols manage this with structured escalation. That structure does not exist outside the trial.
Regulatory position
Cagrilintide holds no marketing authorisation in the UK or elsewhere, alone or in combination. It is not a licensed medicine and cannot be lawfully supplied for human use.
Where this leaves you
Cagrilintide is a real drug candidate with real evidence behind it, and it may well reach approval as part of a combination product. What is circulating on the grey market is a standalone vial of unverified content, used in a configuration that the late-stage evidence base does not primarily describe.