Amycretin: what the early GLP-1 + amylin co-agonist data actually show

Amycretin is one of the more interesting molecules in Novo Nordisk's pipeline, and also one of the easiest to over-read. It is a single peptide that activates two receptors at once — the GLP-1 receptor familiar from semaglutide and the amylin receptor — and it is being developed in both an oral and a subcutaneous form. The early weight-loss figures look large. They also come from Phase 1 studies of a few dozen to a few hundred people, over months, not years. Here is what the primary literature actually shows, and what it does not.

What it is: two receptors, one molecule

Amycretin is described by its developers as a novel, unimolecular GLP-1 receptor and amylin receptor agonist.^[1] The GLP-1 side is well-trodden ground — it is the incretin pathway that drives appetite suppression and glucose-dependent insulin secretion. The amylin side is the newer angle. Amylin is a hormone co-secreted with insulin that promotes satiety and slows gastric emptying; amylin-receptor agonism is the mechanism behind cagrilintide, the amylin analog paired with semaglutide in CagriSema. The conceptual leap with amycretin is that instead of co-formulating two separate drugs, both actions are engineered into a single peptide. In cell-based assays that peptide activated human GLP-1, amylin and calcitonin receptors, and in diet-induced obese rats it cut body weight by about 18% over 21 days while improving insulin sensitivity and liver steatosis.^[3] That is the preclinical rationale; the human data are what matter, and they are early.

The subcutaneous data (phase 1b/2a)

The most quantitatively striking read-out comes from a randomized, placebo-controlled phase 1b/2a study of once-weekly subcutaneous amycretin in adults with overweight or obesity. Between September 2023 and April 2024, 125 participants were randomly allocated to amycretin (101) or placebo (24) at a single research center, across dose-escalation arms running up to 36 weeks.^[1] The estimated mean weight changes were large and dose- and duration-dependent: about −24.3% at 60 mg (week 36), −22.0% at 20 mg (week 36), −16.2% at 5 mg (week 28) and −9.7% at 1.25 mg (week 20), versus placebo changes hovering around plus-or-minus a couple of percent.^[1] Those are eye-catching numbers — in the same neighborhood as the strongest injectables, including the triple agonist retatrutide.

But read the design before the headline. This was a small, single-site, early-phase study whose primary endpoint was the number of treatment-emergent adverse events, not weight.^[1] The most common adverse events were gastrointestinal and mostly mild to moderate, consistent with GLP-1 and amylin agonists — and, importantly, a large number of participants withdrew, though the authors note most discontinuations were for reasons unrelated to side effects.^[1] High dropout in a small trial makes any efficacy estimate fragile. These are signal-generating results, not confirmatory ones.

The oral data (phase 1)

Amycretin is also being developed as a pill, and the first-in-human oral study was published alongside the subcutaneous one. It enrolled 144 participants with overweight or obesity in a double-blind, placebo-controlled, multipart design: single ascending doses, then multiple ascending doses, then a 12-week dose-escalation part in 60 people taking oral amycretin daily at doses escalated up to 50 mg.^[2] Its primary endpoint was safety — specifically the count of treatment-emergent adverse events — with pharmacokinetics as supportive secondary endpoints; body-weight change was only an exploratory endpoint over that 12-week window.^[2] Adverse events were predominantly gastrointestinal and increased in a dose-dependent way, all mild or moderate, with no deaths, and the authors concluded amycretin appeared safe and tolerable and warranted further study of its weight-loss properties.^[2]

So the oral story is genuinely earlier and thinner than the subcutaneous one: the trial was built to answer “is this safe and how does it behave in the body,” not “how much weight does it take off.” If an orally dosed obesity peptide pans out it would matter a great deal for access and adherence — the same reason the small-molecule oral GLP-1 orforglipron is watched so closely — but amycretin's oral efficacy simply has not been established in a powered trial yet.

The honest bottom line

Amycretin pairs a proven mechanism (GLP-1) with a fashionable one (amylin) inside a single molecule, and its early subcutaneous numbers are among the most impressive reported at this stage. That is the good news, stated precisely. The limits are just as real: the efficacy figures come from a single small phase 1b/2a study with notable withdrawals, the oral program is still at the safety-first stage, durations are measured in weeks and months, and there are no long-term outcomes, no head-to-head trials, and no established dose. Cross-trial comparisons to semaglutide or the multi-agonists are suggestive, not definitive. Amycretin is investigational and not approved anywhere. The reasonable posture is curiosity with a firm hand on the brake — this is a promising Phase 1 signal, and Phase 1 signals are exactly the kind that later, larger trials exist to confirm or deflate.