Cagrilintide

Cagrilintide is a lab made copy of amylin, a hormone your body puts out alongside insulin. It is a chain of 37 amino acids, the small building blocks proteins are made from, with a fatty tail added on one end so it clings to a protein in the blood and lasts about a week, which is why it is injected under the skin once a week. It was not built straight from the human hormone. The starting point was pramlintide, an older medicine called Symlin, approved in America in 2005 and taken three times a day with meals, and that approval and that safety record stay with pramlintide. Cagrilintide itself is not approved, on its own or joined to anything else, in America or anywhere else the entry could find. Most of it is tested joined to semaglutide in a single pen called CagriSema, and most of the numbers printed beside the cagrilintide name were earned by that pen.

It copies amylin. A paper published in April 2025 froze the molecule in place and imaged it latching onto all three amylin docking points on a cell, AMY1R, AMY2R and AMY3R, and onto a related calcitonin docking point as well, so it is not fussy about which one it lands on. That the weight loss actually runs through those docking points has been shown only in mice, where animals bred without two of them lost no weight on it at all. In people the entry reports the result rather than the route: weight comes off, and about half as much of it comes off as with the pen that also holds semaglutide, over the same 68 weeks.

People buy it to lose weight. That is also what its trials measured, along with blood sugar in adults with type 2 diabetes, where at 68 weeks it moved the three month blood sugar average by 0.80 percentage points against 1.75 on semaglutide. What is sold is 5 mg and 10 mg vials labelled research chemical, not for human consumption.

The costly mistake is paying for one drug on another drug's numbers. The percentage usually printed beside the cagrilintide name is 20.4 percent of body weight over 68 weeks, and that belongs to the pen holding both drugs. The single agent arm of the same trial, the same 68 weeks, the same kind of people, came out at 11.8 percent. About half, and semaglutide is doing most of the work. The dose has the same problem. 2.4 mg a week is semaglutide's share of the fixed pen, so the maintenance target people copy for cagrilintide alone was set by the other half of a product cagrilintide alone is not in, and the only dose finding trial the single agent has had found 4.5 mg did better than 2.4.

Three things sit in the record that do not reach a product page. Novo's own phase 2 protocol, dated 2 October 2018, records reproductive toxicity work in which rats and mice had major foetal malformations at what the sponsor itself calls human relevant exposures. Rabbits were unaffected despite significantly higher exposure, the mode of action had not been identified, and women who could become pregnant were kept out of the phase 2 trial as a result. Eight years on, the entry found nothing published that resolves it, and what happens in a person is unknown. That same phase 2 trial found antibodies against the drug in 46.3 to 73.2 percent of participants by week 26, most of them also reacting to the person's own natural amylin, with no follow up past 26 weeks that the entry could find. The everyday complaint is the needle site, and that figure comes from REDEFINE 1: reactions where the injection went in ran 17.5 percent on the single agent against 2.6 percent on semaglutide and 12.2 on the combination, roughly seven times more often than semaglutide. Nausea in that trial ran the other way, 23.8 percent against 43.7 on semaglutide and 55.0 on the combination.