The full petrelintide ZUPREME-1 results have now been published in The Lancet Diabetes & Endocrinology and presented at the European Association for the Study of Diabetes (EASD) meeting in Milan on 30 September 2026.
Petrelintide is a once-weekly weight-loss injection that works differently from Wegovy and Mounjaro. In this trial, people lost up to 10.7% of their body weight on average over 42 weeks, and the stomach side-effect numbers are what is getting the attention.
You may have seen it described as a new jab with “half the side effects” of today’s medicines. The trial did not test that, and it is worth understanding why.
Evidence note: ZUPREME-1 is a Phase 2 trial paid for by Zealand Pharma, the company developing petrelintide. It compared petrelintide with a placebo (dummy) injection, not with Wegovy or Mounjaro. Petrelintide is still being tested and is not an approved medicine in the UK. This article is not medical advice. Always speak to an appropriately qualified healthcare professional before making changes to your treatment.
What’s Happened?
Three things have happened in just over a week:
- The full results are now in a medical journal. The ZUPREME-1 paper was published in The Lancet Diabetes & Endocrinology on 29 September 2026. That means the data has been checked by independent experts.
- Extra data was presented at EASD on 30 September, including results on waist size and other health markers.
- The big Phase 3 trials have started. Zealand Pharma announced on 22 September that its final-stage ZUPREME programme is under way.
Not all of this is brand new. The headline 10.7% weight-loss figure was first announced in March 2026, and the side-effect numbers were first presented in June. What is new is the full, peer-reviewed paper and the extra detail that comes with it.
What Is Petrelintide?
Petrelintide is not another GLP-1 drug like Wegovy or Mounjaro.
It copies a different hormone called amylin. Your body naturally releases amylin alongside insulin after you eat. One of its jobs is to help tell your brain that you have had enough food.
Petrelintide is designed to give that “I’m full” signal for longer. It is taken as an injection once a week.
It is being developed by the Danish company Zealand Pharma, together with Roche.
Who Was in the Trial?
ZUPREME-1 involved 485 adults who were living with obesity, or who were overweight with high blood pressure or high cholesterol. None of them had type 2 diabetes.
Just over half (53%) were women. The average age was 47, and the average starting weight was 107 kg (about 16 st 12 lb).
People were randomly given one of five doses of petrelintide (from 1 mg to 9 mg) or a placebo, once a week for 42 weeks. Neither they nor their doctors knew which they were getting. Five people got petrelintide for every one who got placebo, so 404 people took petrelintide and 81 took placebo.
The trial ran at 32 sites in Poland, Romania and the USA. There were no UK sites.
How Much Weight Did People Lose?
The main result was measured at 28 weeks. By then, people on petrelintide had lost between 7.9% and 9.8% of their body weight on average, depending on the dose. People on placebo had lost 1.7%.
Weight kept coming down after that. By 42 weeks, average weight loss reached up to 10.7% on petrelintide, compared with 1.7% on placebo.
To put that in everyday terms: for someone at the trial’s average starting weight of 107 kg, 10.7% is roughly 11.5 kg, or about 1 st 11 lb. That is an average, not a prediction for any one person. Some people will have lost more and some less.
Two more things are worth knowing:
- There is a more cautious version of the number. The 10.7% figure estimates what happens if people stay on treatment. Counting everyone, including people who stopped, Zealand Pharma reports up to 10.2% on petrelintide and 1.4% on placebo.
- A bigger dose did not clearly mean more weight loss. At 28 weeks, the middle 5 mg dose had the largest average loss (9.8%), slightly ahead of the 7 mg and 9 mg doses.
Zealand Pharma also reported improvements in other health markers at 42 weeks, including waist size (down by up to 10.8 cm, compared with 4.3 cm on placebo), blood fats and a marker of inflammation.
What About the Side Effects?
This is the part attracting the most interest. With today’s weight-loss jabs, feeling or being sick is the most common reason people struggle.
Here is what the trial found, across everyone taking petrelintide compared with placebo:
- Nausea (feeling sick): 19.6% on petrelintide, 6.2% on placebo.
- Vomiting (being sick): 3.0% on petrelintide, 6.2% on placebo.
- Diarrhoea: 7.4% on petrelintide, 7.4% on placebo.
- Constipation: 6.9% on petrelintide, 3.7% on placebo.
So nausea was clearly more common on petrelintide: about one in five people, compared with about one in sixteen on placebo. The researchers say it was mostly mild and mostly happened while doses were being stepped up.
The other stomach side effects were about as common on petrelintide as on the dummy injection.
According to Zealand Pharma, more than three-quarters of stomach side effects were mild, and only 1.5% of people stopped petrelintide because of them.
It was not side-effect free. No deaths were reported. But an independent UK expert who reviewed the paper noted three serious side effects thought to be linked to petrelintide: two cases of gallstones and one of pancreatitis caused by a blockage.
Is It Really “Half the Side Effects” of Mounjaro and Wegovy?
We cannot say that from this trial.
ZUPREME-1 compared petrelintide with a placebo. It did not compare petrelintide with Mounjaro, and it did not compare it with Wegovy.
The “half” claim comes from putting petrelintide’s nausea rate next to nausea rates from completely separate trials of other medicines. That is not a fair test. Those trials had different people, different lengths, different doses and different ways of counting side effects.
The honest version is this: the stomach side-effect numbers look encouraging. But until petrelintide is tested directly against Mounjaro or Wegovy in the same trial, nobody can say it definitely causes fewer side effects.
Independent experts have said the same. Dr Marie Spreckley of the University of Cambridge, commenting through the Science Media Centre, said larger and longer trials, including a direct comparison, are needed before claims about better tolerability can be made.
How Is It Different From Mounjaro and Wegovy?
The main difference is the hormone it copies.
- Wegovy (semaglutide) copies a gut hormone called GLP-1.
- Mounjaro (tirzepatide) copies two gut hormones, GLP-1 and GIP.
- Petrelintide copies amylin, a fullness hormone released alongside insulin.
It is tempting to line up 10.7% against the weight-loss figures for Mounjaro and Wegovy. But that has the same problem as the side-effect comparison. The trials were different lengths, with different people and different designs, so the numbers cannot simply be set side by side.
What we can say is that Mounjaro and Wegovy are approved medicines with large, long trials behind them. Petrelintide has one Phase 2 trial lasting 42 weeks. You can read more about the approved options in our Mounjaro UK guide and Wegovy UK guide.
Petrelintide is also not the only amylin-based medicine being developed. We have covered two others: cagrilintide and eloralintide.
Can You Get Petrelintide in the UK?
No.
Petrelintide is an investigational medicine, which means it is still being tested. It has not been approved by the MHRA, the UK medicines regulator, and it is not available as an approved weight-loss medicine in the UK, on the NHS or privately.
No UK approval date has been announced, and we are not going to guess one. The Phase 3 trials have only just started and need to finish first.
Anything sold online as “petrelintide” is not an approved medicine and should not be assumed to be the same as the product used in the trial.
What Happens Next?
The Phase 3 ZUPREME programme began in September 2026. It is made up of three large trials involving around 7,000 people in total:
- ZUPREME-3: about 3,900 people with obesity or overweight who do not have type 2 diabetes.
- ZUPREME-4: about 600 people with obesity or overweight who do have type 2 diabetes.
- ZUPREME-5: about 2,500 people with obesity or overweight and existing heart or circulation disease, followed for up to three years.
All three compare petrelintide with placebo, and the main weight-loss result will be measured at 64 weeks. That is longer than ZUPREME-1, so it should show whether the weight loss continues and whether the side-effect picture holds up in far more people.
The Bottom Line
Petrelintide has now produced double-digit average weight loss in a Phase 2 trial, with unusually encouraging stomach side-effect figures. That is enough to make it one of the more interesting next-generation obesity medicines to watch.
But it has not been tested directly against today’s GLP-1 medicines, so the “half the side effects” claim is not proven. Phase 3 still has to confirm the picture, and petrelintide is not available in the UK.
Frequently Asked Questions
What did the petrelintide ZUPREME-1 results show?
In 485 adults with obesity or overweight and no type 2 diabetes, once-weekly petrelintide led to average weight loss of 7.9% to 9.8% at 28 weeks, and up to 10.7% at 42 weeks, compared with 1.7% on placebo.
Does petrelintide have fewer side effects than Mounjaro or Wegovy?
That has not been tested. ZUPREME-1 compared petrelintide with placebo only. Nausea affected 19.6% of people on petrelintide and 6.2% on placebo, and other stomach side effects were similar to placebo. A direct comparison trial would be needed to show it causes fewer side effects than other medicines.
Is petrelintide a GLP-1?
No. Petrelintide copies amylin, a hormone released alongside insulin after eating that helps you feel full. Wegovy and Mounjaro work on different hormones.
Is petrelintide available in the UK?
No. It is still being tested and has not been approved by the MHRA. No UK approval date has been announced.
When will the Phase 3 results be available?
The Phase 3 trials started in September 2026 and their main results are measured at 64 weeks, so they will take time. Zealand Pharma has not given a results date in its announcement.
Key Takeaways
- The full Phase 2 ZUPREME-1 results for petrelintide were published in The Lancet Diabetes & Endocrinology on 29 September 2026 and presented at EASD on 30 September.
- In 485 adults without type 2 diabetes, average weight loss was 7.9% to 9.8% at 28 weeks and up to 10.7% at 42 weeks, compared with 1.7% on placebo.
- Counting everyone, including people who stopped treatment, the 42-week figures were up to 10.2% on petrelintide and 1.4% on placebo.
- Nausea affected 19.6% of people on petrelintide and 6.2% on placebo. Vomiting, diarrhoea and constipation were about as common as on placebo.
- The trial compared petrelintide with placebo, not with Mounjaro or Wegovy, so the “half the side effects” claim has not been tested.
- Petrelintide copies the fullness hormone amylin. It is not a GLP-1 medicine.
- Phase 3 trials involving around 7,000 people started in September 2026.
- Petrelintide is investigational and is not approved or available as a medicine in the UK.
Further Reading
Cagrilintide UK: What Is Cagri and Why Is Everyone Suddenly Talking About It?
Eloralintide: What Is It and Why Are People Comparing It to Cagrilintide?
Retatrutide TRIUMPH-2 Results: What the Full Type 2 Diabetes Data Actually Shows
Sources
Garvey WT, Ard J, Connery L, et al. Petrelintide, a human amylin analogue for the treatment of obesity (ZUPREME 1): a randomised, double-blind, placebo-controlled, phase 2 trial. The Lancet Diabetes & Endocrinology, published online 29 September 2026. doi:10.1016/S2213-8587(26)00213-5
Roche (5 March 2026) — Positive Phase II results for petrelintide
ClinicalTrials.gov — NCT06662539 (ZUPREME-1)
This article is for information purposes only and does not constitute medical advice. Petrelintide is an investigational medicine and is not approved in the UK. Always consult a qualified healthcare professional before starting, stopping or changing any treatment.
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About this article
This article is for information purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any treatment. Information correct at time of publication. The Peptide Brief updates articles when guidance changes.
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