Every few months a new obesity drug name appears in the headlines with a very large percentage attached, and the honest question underneath is always the same: is this a step change, or is it a small early trial being read as though it were a finished one?

Amycretin is worth understanding on both counts. The mechanism genuinely is new, and the headline trial genuinely was small. It also gets confused with MariTide constantly, which is fair enough given they hit the news at the same time, but they are different drugs from different companies pulling in opposite directions. MariTide has its own page.

First, the name changed

If you go looking for recent research you will hit a wall, because the drug now has a different name. Amycretin was the development code. Zenagamtide is the international non-proprietary name, the permanent generic name a drug gets as it moves towards approval, in the way semaglutide is the generic name behind Wegovy.

The switch is recent enough to be genuinely confusing: Novo Nordisk's Lancet papers of 30 July 2026 open by spelling out that zenagamtide was formerly amycretin. Same molecule, internally coded NNC0487-0111. Most trial registry entries still use the code. Search for either name and you will find half the story, which is worth knowing if you are trying to keep up with this yourself.

What it is

A unimolecular receptor agonist, which unpacks into something simple: one molecule that switches on several appetite pathways at once, rather than several drugs mixed together.

The GLP-1 part is familiar, the same receptor semaglutide works on. The newer part is amylin. The 2025 papers describe it as a GLP-1 and amylin receptor agonist, and the 2026 papers add a third: it is also active at the calcitonin receptor. So the common shorthand of "dual agonist" is not quite the full picture, which is a small detail that tells you something about how quickly the understanding of these molecules is still moving.

Novo Nordisk is developing two forms in parallel: a once-weekly injection and a once-daily tablet. The tablet is the strategically interesting one, because getting a peptide past the digestive system is the hard problem in this field.

The amylin part, in plain English

Amylin is a hormone your pancreas releases alongside insulin when you eat. It slows how fast the stomach empties and signals fullness through a different route in the brain from GLP-1. Two satiety systems, arriving at the same destination by different roads.

The reasoning behind combining them is that hitting two pathways might do more than pushing one to its ceiling, and might do it with less of the nausea that limits the dose. That is the hypothesis. It is the same thinking behind CagriSema, which pairs semaglutide with the amylin analogue cagrilintide as two compounds in one injection. Amycretin does it with a single molecule, which is real pharmaceutical engineering rather than a marketing distinction: one molecule means one set of pharmacokinetics to manage instead of two that have to be kept in step.

What the injection trial found

The headline figures come from a phase 1b/2a trial published in The Lancet in July 2025. It ran at a single centre in San Antonio, Texas, from September 2023 to April 2024, and randomised 125 adults aged 18 to 55 with a BMI between 27.0 and 39.9, with 101 on amycretin and 24 on placebo.

Striking numbers. Now the three things that should temper how you read them, none of which is a reason to dismiss the drug.

It was a proof-of-concept study. Phase 1b/2a exists to answer "does this do anything, and is it tolerable enough to continue". This one answered yes to both. It does not tell you what happens across thousands of people over 18 months, and early-phase percentages have a long history of shrinking as trials get bigger.

Look at the placebo column. In three of the four dose groups the placebo arm gained weight. That widens the gap between drug and placebo compared with a trial like STEP 1, where the placebo group lost 2.4%. It is a normal feature of small groups, and it is a reason the headline difference flatters slightly.

Tolerability was the real story. The Lancet authors report that gastrointestinal events were the most common problem, mostly mild to moderate, and that a large number of participants withdrew, though a high proportion of those withdrawals were for reasons unrelated to side effects. Secondary reports quote specific symptom rates that I could not confirm against the paper itself, so I have left them out rather than repeat numbers I cannot stand behind.

The tablet version

A separate phase 1 first-in-human trial tested a once-daily oral form in 144 adults for up to 12 weeks. At the top dose, two 50mg tablets taken together once a day, mean weight loss was 13.1% against 1.2% on placebo. A single 50mg tablet daily gave 10.4%.

Two caveats worth carrying. Twelve weeks is a short window, so read that as evidence the oral route works at all rather than a measure of where it lands. And the weight figures were exploratory: the trial's primary endpoint was counting side effects, which is what a first-in-human study is for. Of the 144 participants, 89 had at least one treatment-emergent adverse event, all mild or moderate, with gastrointestinal symptoms the most common. No deaths.

You will see this drug described as "50mg twice daily" in places. The paper says two tablets in a single daily dose, which is not the same instruction. If you want the practical reality of taking an oral GLP-1, with the empty-stomach rules and the waiting period, we cover it in the Wegovy pill guide.

The type 2 diabetes trials

Two more Lancet papers landed on 30 July 2026, both from one phase 2 programme run across 83 sites in 11 countries in adults with type 2 diabetes on metformin. This is a much bigger and more geographically spread piece of work than the obesity studies, and it is the reason Novo Nordisk moved as decisively as it did.

On the injection side, 262 people were randomised across six doses plus placebo. HbA1c fell by 0.9% at the lowest dose and 1.7% at the highest, from a baseline of 7.8%. Novo Nordisk reported weight loss of 14.6% at the 40mg dose against 2.1% on placebo, a figure that comes from the company's own announcement rather than the peer-reviewed abstract. It carries a real caveat: at the top doses, people spent only about four weeks at the maintenance dose, so most of that weight loss happened while the dose was still climbing.

On the tablet side, 186 people were randomised. HbA1c fell 1.4% at the 50mg dose against placebo. Gastrointestinal side effects ran at 26% on the lowest dose, 41% in the middle and 47% at the top, against 23% on placebo, which is the cleanest dose-response picture available for this drug. Weight figures for the oral diabetes arm have not been published outside the paywalled paper, so I am not going to quote one.

One thing worth knowing generally: weight loss is consistently smaller in people with type 2 diabetes across this entire drug class, in every trial programme, for reasons still being worked out. It is another reason a headline percentage from one population tells you little about another.

How it compares, carefully

Here is the comparison everyone wants, with the caveat that matters more than the table: these are separate trials, not a head-to-head. Different people, durations, sites and analysis methods.

Read those as three separate facts sitting next to each other, not a ranking. The amycretin figure comes from 101 treated people at one clinic; the tirzepatide figure from a trial twenty times the size that ran twice as long. A phase 3 number has survived a test the early-phase number has not yet faced.

The good news is that this will eventually be settled properly. Two head-to-head trials against semaglutide, AMAZE 7 and AMAZE 8, are registered. Neither had begun recruiting as of July 2026, and neither reports before late 2028.

When you could actually get it

The phase 3 programme is called AMAZE, and it is large: at least twelve registered trials covering obesity, type 2 diabetes, sleep apnoea, knee osteoarthritis, weight maintenance, and a 5,610-person heart failure outcomes study.

AMAZE 1, the flagship obesity trial, began recruiting in February 2026 with 1,150 participants and has a primary completion date of June 2029. Regulatory review comes after that, and no submission has been made anywhere yet. So the realistic answer is: not this decade, probably. If you are weighing up treatment now, amycretin is not one of your options, and anyone implying otherwise is selling something.

There is a genuine UK angle, though. Twelve UK sites are recruiting for AMAZE 1, most of them ordinary GP practices rather than research hospitals, from Fowey and Poole to Rotherham, Nantwich and Wellingborough. A further four are recruiting for the weight-maintenance trial, and 37 UK hospitals are involved in the heart failure study. If you have ever wondered how to get access to a next-generation obesity drug legally, a trial is the only honest answer, and the registry entry lists the sites and eligibility criteria. Talk to your GP first.

Our pipeline tracker keeps approval status for every drug in this queue with the date it was last checked, and the options explorer covers what is actually licensed where you live.

FAQ

What is amycretin?

An investigational obesity medicine from Novo Nordisk, now formally named zenagamtide. One molecule that activates the GLP-1 receptor plus the amylin and calcitonin receptors. In development as both a weekly injection and a daily tablet. Not approved anywhere.

Why is it now called zenagamtide?

Amycretin was the development code name; zenagamtide is the permanent generic name assigned as a drug advances, the way semaglutide sits behind Wegovy. Novo Nordisk's July 2026 Lancet papers confirm they are the same molecule.

How much weight did people lose?

Injection, 36 weeks, 125 people: -24.3% at 60mg and -22.0% at 20mg, against placebo arms that lost 1.1% and gained 1.9% respectively. Tablet, 12 weeks, 144 people: -13.1% at the top dose. Small, short, single-centre trials.

Is it better than Mounjaro or Wegovy?

Unknown. It has never been tested against either. The head-to-head trials that will answer this do not report until late 2028.

When will it reach the UK?

Not before the end of the decade on current timelines. The flagship phase 3 trial completes in June 2029 and no regulatory submission has been made. Twelve UK sites are recruiting for it now, which is the only legitimate route to access today.

This article is information, not medical advice. Decisions about starting, changing or stopping any weight-loss medication belong with you and your prescriber.

Whatever ends up in the syringe or the tablet in five years, what decides how much of the weight stays off is what you build around it. The evidence for keeping a diary is worth reading whichever medicine you are on, and you can start tracking free.