What Is Petrelintide? The Amylin Analog Betting on Fewer GI Effects

A new obesity drug usually arrives with one number attached: how much weight came off. Petrelintide arrived with a different one: how many people felt sick. It is an investigational once-weekly amylin analog from Zealand Pharma, and it is being positioned less as the strongest option in the room and more as the one a person might actually stay on. The wider amylin field is being sold on that same promise of an easier stomach. It is a good pitch, and as of July 2026 it rests on two small Phase 1 trials, because the larger Phase 2 study that would test it finished months ago without posting a single result to the registry.^{[1, 5]}

What petrelintide actually is

Petrelintide, also written ZP8396, is a long-acting analog of human amylin. Amylin is a hormone the pancreas releases alongside insulin after a meal. It slows gastric emptying, suppresses glucagon, and signals through the brain that the meal is over, which is the reason this class is being studied for weight management at all. The chemistry paper describing the molecule reports that Zealand's team optimised it for chemical stability at close to neutral pH while keeping potency, so it can sit in one formulation with other peptides rather than a separate one. In the human trials it is given as a weekly injection, and its half-life came out at roughly 10 days. Semaglutide and tirzepatide work on a different receptor system, GLP-1, and in tirzepatide's case GIP as well, so petrelintide is not a variation on those drugs. It is a separate pathway into the same problem.^{[1, 2, 3]}

Where the tolerability story comes from

One paper, published in Diabetes, Obesity and Metabolism in 2026, reports both Phase 1 trials: a single ascending dose study and a multiple ascending dose study. The authors describe petrelintide as well tolerated, with no serious or severe treatment-emergent adverse events in either trial. Gastrointestinal disorders were the most common category of adverse event, and most were mild. Nausea, the most frequent gastrointestinal event, was reported by 16.7% to 33.3% of participants receiving petrelintide against 16.7% on placebo in the second part of the multiple-dose study. One participant stopped because of gastrointestinal events. Body weight came down by up to 8.6% after 16 weeks. That is the entire published human tolerability record for this compound. Phase 1 trials are designed to characterise safety and pharmacokinetics, not to measure how well a drug works. And at the top of the reported range, a third of the people receiving petrelintide were nauseous, which is double the placebo rate inside the same study.^[1]

What the wider amylin literature says about nausea

Two 2026 reviews put that claim in context, and neither is as tidy as the marketing. A review in Peptides covering long-acting amylin-related peptides states plainly that gastrointestinal side effects, especially nausea, similar to those reported for GLP-1 receptor agonists, are commonplace when people start these drugs and when weekly doses step up, though they mostly settle with continued use. A narrative review in Diabetes, Obesity and Metabolism surveyed every amylin-based therapy in human development as of 30 April 2026 and called the class generally favourable on tolerability, but it offers no head-to-head comparison against a GLP-1 drug, because none has been published. Within the class the numbers scatter badly. Eloralintide, Eli Lilly's selective amylin receptor agonist, reported nausea in 11% to 64% of participants depending on the dose arm across a 48-week Phase 2 trial, against 14% on placebo. The word amylin on its own predicts very little about how a stomach will feel. The specific molecule matters, the speed at which doses rise matters, and for petrelintide neither has been tested at Phase 2 scale in public.^{[3, 4, 8]}

How far the programme has actually got

ZUPREME-1, registered as NCT06662539, is the study that would settle this. It is a randomised, double-blind, dose-finding Phase 2 trial of once-weekly petrelintide against placebo in people with obesity, or overweight with weight-related comorbidities. It enrolled 493 participants across 32 sites in the United States, Poland and Romania, ran from December 2024, and completed in March 2026. Its primary endpoint is percent change in body weight at week 28, with further body-weight measures at week 42 and adverse-event follow-up out to week 51. As of 26 July 2026 no results are posted on ClinicalTrials.gov and no peer-reviewed report has appeared. A second Phase 2 study, ZUPREME-2 (NCT06926842), is running in people who have overweight or obesity alongside type 2 diabetes. It enrolled 221 participants, is active but no longer recruiting, and its primary completion date is estimated at 13 August 2026. A registry search returns six interventional petrelintide studies in total, and the highest phase among them is Phase 2. A Roche-sponsored Phase 2 dose-finding study pairing petrelintide with enicepatide (NCT07589686) is listed with 486 planned participants but has not started recruiting.^{[5, 6, 7, 9]}

How it sits next to the GLP-1 drugs

The pathway difference is real, but maturity is the wider gap. Semaglutide and tirzepatide each have large published Phase 3 programmes and branded prescription products behind them. Petrelintide's published human record is two Phase 1 trials and a chemistry paper. No trial has compared petrelintide against any GLP-1 drug head to head, so every comparison circulating online is cross-trial arithmetic: different participants, different durations, different endpoints. Even the pooled GLP-1 numbers refuse to line up against petrelintide's. A 2025 Bayesian network meta-analysis of 48 randomised trials and 27,729 participants with type 2 diabetes found tirzepatide carried the highest nausea risk in the class, and reported nausea as the most frequent gastrointestinal event at 21.49% against an overall gastrointestinal adverse-event incidence of 11.66%. That 21.49% is nausea's share of the gastrointestinal events counted, not the proportion of participants who felt sick, so it is not the same measurement as petrelintide's participant-level 16.7% to 33.3% and the two cannot honestly be set against each other. On withdrawals rather than symptoms, STEP 1 followed 1,961 adults for 68 weeks and 4.5% of the semaglutide group came off treatment because of gastrointestinal events, against 0.8% on placebo, while petrelintide's Phase 1 programme logged a single such withdrawal across trials running 16 weeks at most. Neither figure is a comparison with petrelintide, but both show the scale at which the GLP-1 drugs have been measured and petrelintide has not. If you want a head-to-head where both sides carry published Phase 3 evidence, /compare/tirzepatide-vs-semaglutide is the one that exists, and /compare/cagrilintide-vs-retatrutide is the closest thing to an amylin entry on this site. Petrelintide is not at that table yet, and the honest version of the tolerability pitch is a hypothesis waiting on ZUPREME-1 rather than a finding.^{[1, 2, 5, 10, 11]}

What the evidence does not show

Nothing published follows body weight past 16 weeks of exposure. The week-42 measures and the week-51 adverse-event follow-up from ZUPREME-1 exist only as unreported endpoints on the registry. Whether the gentler gastrointestinal profile holds at the exposures needed for larger weight loss is unsettled, since the Phase 1 nausea rate already spanned 16.7% to 33.3% across the petrelintide groups. Nothing published describes what happens to body weight once the weekly injections stop. And no Phase 3 study appears on the registry, so there is no confirmatory efficacy or long-term safety dataset for anyone to read.^{[1, 5, 9]}

Regulatory status and what is sold online

Petrelintide is not approved by the FDA for any use, and it is not approved anywhere else. It is not sold as a medicine or as a supplement, and the only people with legitimate access to it are participants in the trials above. Material advertised online under the petrelintide name sits outside the clinical programme, so nobody is verifying its identity, its purity, or what is in it. None of the published evidence describes material obtained that way, so none of the numbers on this page can be assumed to travel with it. The compound sheet on this site is at /peptides/petrelintide.^{[5, 9]}

References & sources

1. Brændholt Olsen M, Griffin J, Hövelmann U, et al. Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Petrelintide for Weight Management: Two Randomized, Controlled Phase 1 Trials. Diabetes Obes Metab. 2026;28(7):5915-5925. PMID 42017294.
2. Fischer Munch H, Just R, Mathiesen JM, et al. Development of Petrelintide: a Potent, Stable, Long-Acting Human Amylin Analogue. J Med Chem. 2025. PMID 41217931.
3. Bailey CJ, Flatt PR, Conlon JM. Long-acting amylin-related peptides as therapies for obesity and type 2 diabetes. Peptides. 2026;196:171480. PMID 41747885.
4. Alhazmi A, le Roux CW. Amylin Analogs: The Next Major Class of Weight Loss Therapy: A Review of Experimental Data and Early-Phase Clinical Trials. Diabetes Obes Metab. 2026. PMID 42452898.
5. NCT06662539: A Randomized, Double-blind, Phase 2, Dose-finding Trial of Once Weekly Petrelintide Compared With Placebo in Participants With Obesity or Overweight With Weight Related Comorbidities (ZUPREME-1). Zealand Pharma; 493 participants; completed 7 March 2026; no results posted as of 26 July 2026. ClinicalTrials.gov.
6. NCT06926842: A Randomized, Double-Blind, Phase 2 Trial of Once-Weekly Petrelintide Compared With Placebo in Participants With Overweight or Obesity and Type 2 Diabetes (ZUPREME-2). Zealand Pharma; 221 participants; active, not recruiting. ClinicalTrials.gov.
7. NCT07589686: A Dose-Finding Study of Petrelintide With Enicepatide (RO7795068) in Adults With Obesity or Overweight. Hoffmann-La Roche; Phase 2; 486 planned participants; not yet recruiting as of 26 July 2026. ClinicalTrials.gov.
8. Billings LK, Hsia S, Bays H, et al. Eloralintide, a selective amylin receptor agonist for the treatment of obesity: a 48-week phase 2, multicentre, double-blind, randomised, placebo-controlled trial. Lancet. 2025;406(10520):2631-2643. PMID 41207310.
9. ClinicalTrials.gov registry search for petrelintide interventional studies (checked 26 July 2026; six studies returned, highest registered phase is Phase 2).
10. Xie X, Yang S, Deng S, et al. Comparative gastrointestinal adverse effects of GLP-1 receptor agonists and multi-target analogs in type 2 diabetes: a Bayesian network meta-analysis. Front Pharmacol. 2025;16:1613610. PMID 41050409.
11. Wilding JPH, Batterham RL, Calanna S, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med. 2021;384(11):989-1002. PMID 33567185.