Petrelintide vs Semaglutide (2026): Amylin Analogue vs GLP-1 Agonist Trial Data
Petrelintide vs semaglutide: up to 10.7% weight loss at 42 weeks in ZUPREME-1 vs 14.9% at 68 weeks in STEP 1. See where amylin and GLP-1 agonism diverge.
Research reference only. The information in this article is a summary of peer-reviewed scientific literature. It does not constitute medical advice and is not intended to guide human use. See our full disclaimer.
Petrelintide vs semaglutide is the comparison researchers reach for when they want to know how a long-acting amylin analogue measures up against the GLP-1 receptor agonist that defined the modern incretin era. Petrelintide (ZP8396, RG6849), co-developed by Zealand Pharma and Roche, entered the Phase 3a ZUPREME program on September 22, 2026, after Phase 2 ZUPREME-1 data were presented at EASD 2026. Semaglutide, developed by Novo Nordisk, is the approved reference compound with the largest outcomes dataset in the class. This guide sets out what each molecule targets, what the published trials report, and why the two are increasingly studied as complements rather than rivals.
Research reference only. All information on this page is a summary of peer-reviewed scientific literature and does not constitute medical advice. See individual library profiles for full compound data.
Quick Answer: Petrelintide is an investigational once-weekly amylin analogue that produced up to 10.7% mean weight loss at 42 weeks in Phase 2 ZUPREME-1, while semaglutide is an approved once-weekly GLP-1 receptor agonist that produced 14.9% at 68 weeks in STEP 1. They act on different receptor systems, and the trials are separate, so any efficacy comparison is indirect.
TL;DR:
- Petrelintide activates amylin receptors (calcitonin receptor/RAMP complexes); semaglutide activates the GLP-1 receptor.
- Petrelintide is in Phase 3a (ZUPREME-3, -4, -5); semaglutide is approved for type 2 diabetes and chronic weight management.
- Phase 2 ZUPREME-1 reported up to 10.7% weight loss at 42 weeks with no vomiting in the maximally effective arm.
- STEP 1 reported 14.9% vs 2.4% at 68 weeks; SELECT reported a 20% reduction in major adverse cardiovascular events.
- The main research hypothesis for amylin agonism is comparable satiety signalling with a lower gastrointestinal adverse-event burden.
| Parameter | Petrelintide | Semaglutide |
|---|---|---|
| Developer | Zealand Pharma / Roche | Novo Nordisk |
| Receptor target | Amylin receptors (CTR/RAMP) | GLP-1 receptor |
| Development stage (Oct 2026) | Phase 3a (ZUPREME) | Approved (US, EU and others) |
| Key weight-loss figure | Up to 10.7% at 42 weeks (ZUPREME-1, efficacy estimand) | 14.9% at 68 weeks (STEP 1, 2.4 mg) |
| Placebo arm | 1.7% | 2.4% |
| Dosing interval | Once weekly, subcutaneous | Once weekly subcutaneous; once-daily oral formulation also studied |
| Half-life | ~10 days | ~7 days (~165 hours) |
Petrelintide: mechanism and evidence base
Petrelintide is a long-acting human amylin analogue. Native amylin is co-secreted with insulin from pancreatic beta cells and acts on receptors formed when the calcitonin receptor pairs with one of three receptor activity-modifying proteins (RAMP1–3). Activation in the area postrema and hypothalamus promotes satiation, slows gastric emptying and suppresses postprandial glucagon. Native amylin aggregates into fibrils and is short-lived, which is why earlier analogues such as pramlintide required mealtime dosing. Petrelintide was engineered for chemical and physical stability at neutral pH, a property that also allows it to be co-formulated with other peptides. Full compound data are on the petrelintide library profile.
The first peer-reviewed human data came from two randomised, placebo-controlled Phase 1 trials published in Diabetes, Obesity and Metabolism (PMID 42017294). The single ascending dose trial tested 0.04–2.4 mg subcutaneously, and the multiple ascending dose trial evaluated six once-weekly doses. Investigators reported no serious or severe adverse events, mostly mild gastrointestinal effects, a half-life of about 10 days and up to 8.6% body-weight reduction after 16 weeks.
Phase 2 ZUPREME-1 (NCT06662539) enrolled 493 adults with obesity or overweight without type 2 diabetes. Mean weight loss reached up to 10.7% at week 42 versus 1.7% with placebo under the efficacy estimand (10.2% vs 1.4% under the treatment-policy estimand). Waist circumference fell by up to 10.8 cm and hsCRP by up to 41%. Zealand reported no vomiting and no GI-driven discontinuations in the maximally effective arm. The results were published in The Lancet Diabetes & Endocrinology in September 2026; a PubMed identifier had not been confirmed at the time of writing.
Semaglutide: mechanism and evidence base
Semaglutide is a GLP-1 receptor agonist with 94% sequence homology to native GLP-1. An Aib substitution at position 8 confers resistance to DPP-4 degradation, and a C18 fatty diacid side chain drives albumin binding, extending the half-life to roughly one week. GLP-1 receptor activation enhances glucose-dependent insulin secretion, suppresses glucagon and acts on hypothalamic and brainstem circuits that reduce food intake. The semaglutide library profile and the semaglutide mechanism of action guide cover receptor signalling in detail.
The pivotal obesity dataset is STEP 1 (PMID 33567185), in which 1,961 adults without diabetes received semaglutide 2.4 mg once weekly or placebo for 68 weeks. Mean body-weight change was −14.9% versus −2.4%. Gastrointestinal events, mostly nausea and diarrhoea, were the most frequent adverse events and were the leading cause of discontinuation. The SELECT trial (PMID 37952131) then randomised 17,604 adults with established cardiovascular disease and overweight or obesity, but without diabetes, and reported a 20% relative reduction in major adverse cardiovascular events over a mean follow-up of 39.8 months.
The literature also includes rarer safety signals. A 2026 case report (PMID 42027588) described reversible nocturnal hypercapnia after dose escalation to 1 mg per week, which resolved after discontinuation. Single case reports cannot establish causation, but they illustrate the scale of post-approval pharmacovigilance that an investigational compound such as petrelintide does not yet have.
Side-by-side comparison
| Feature | Petrelintide | Semaglutide |
|---|---|---|
| Peptide class | Amylin analogue | GLP-1 analogue |
| Primary satiety site | Area postrema, hypothalamus | Hypothalamus, brainstem |
| Gastric emptying | Slowed | Slowed (attenuates with chronic exposure) |
| Glucagon | Suppresses postprandial | Suppresses (glucose-dependent) |
| Insulin secretion | No direct insulinotropic effect | Glucose-dependent stimulation |
| Leading GI signal | Mild nausea; no vomiting in top arm (ZUPREME-1) | Nausea, diarrhoea, vomiting (STEP 1) |
| Cardiovascular outcomes data | None yet; ZUPREME-5 enrolling | SELECT: 20% MACE reduction |
| Co-formulation stability | Engineered for neutral pH | Formulated with cagrilintide in CagriSema |
| Regulatory status | Investigational | FDA and EMA approved |
The half-life figures can be visualised against other incretin and amylin compounds on the peptide half-life chart.
Differential research applications
Researchers studying appetite regulation have used the two compounds to probe different questions. Semaglutide is the reference standard for GLP-1 receptor pharmacology, glycaemic control, and cardiovascular and renal outcomes. Its large trial base makes it the default comparator arm in incretin studies and the benchmark against which new mechanisms are judged.
Petrelintide is selected when the question is whether amylin-pathway satiety can deliver meaningful weight loss with a gentler tolerability profile. Zealand has framed the programme around quality of weight loss and tolerability rather than maximum percentage loss. The ZUPREME-1 tolerability pattern, with GI adverse events reported as similar to placebo in the highest-efficacy arm, is the key differentiator in the published data so far. Its stability at neutral pH also makes it a candidate for fixed-dose combinations: a Phase 2 trial (NCT07589686) pairs petrelintide with Roche's GLP-1/GIP agonist enicepatide (CT-388).
The combination rationale is already supported in a related pairing. Novo Nordisk's CagriSema couples the amylin analogue cagrilintide with semaglutide, and the REDEFINE 1 trial (PMID 40544433) reported greater weight loss with the combination than with either component alone. That result is the main reason amylin analogues are now studied alongside GLP-1 agonists rather than only against them. Lilly's eloralintide and Novo's unimolecular amycretin extend the same logic. Trial registrations and readouts for all of these programmes can be followed in the clinical trial tracker.
Two caveats apply to any cross-trial reading. ZUPREME-1 ran for 42 weeks and STEP 1 for 68 weeks, and petrelintide's dose escalation was still optimising. Populations, estimands and baseline BMI also differ, so the 10.7% and 14.9% figures should not be read as a head-to-head result.
Regulatory and compounding status
Petrelintide is investigational. It has no FDA or EMA approval, and the Phase 3a ZUPREME programme comprises ZUPREME-3 (about 3,900 participants without type 2 diabetes), ZUPREME-4 (about 600 with type 2 diabetes) and ZUPREME-5 (about 2,500 with established cardiovascular disease), with a primary endpoint of percentage body-weight change at week 64. As an unapproved investigational peptide it is not eligible for 503A or 503B compounding.
Semaglutide is FDA- and EMA-approved for type 2 diabetes and chronic weight management, and its label includes cardiovascular risk reduction based on SELECT. After the FDA removed semaglutide from its drug shortage list in February 2025, the temporary allowance for compounders to produce essentially copies of the approved product ended, and pharmacy compounding of semaglutide has been subject to continuing FDA enforcement attention since.
Neither compound is a named substance on the WADA Prohibited List; anti-doping researchers should consult the current list, as GLP-1 class agents are reviewed periodically.
Cited studies
- PMID 42017294: "Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Petrelintide for Weight Management: Two Randomized, Controlled Phase 1 Trials" (Diabetes, Obesity and Metabolism, 2026). https://doi.org/10.1111/dom.70753
- ZUPREME-1 Phase 2 (NCT06662539), The Lancet Diabetes & Endocrinology, September 2026; PMID pending indexing.
- PMID 33567185: "Once-Weekly Semaglutide in Adults with Overweight or Obesity" (New England Journal of Medicine, 2021). https://doi.org/10.1056/NEJMoa2032183
- PMID 37952131: "Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes" (New England Journal of Medicine, 2023). https://doi.org/10.1056/NEJMoa2307563
- PMID 42027588, "Unexplained hypercapnia with normal pulmonary evaluation in a patient receiving semaglutide: a diagnostic challenge" (JCEM Case Reports, 2026). https://doi.org/10.1210/jcemcr/luag121
- PMID 40544433 · REDEFINE 1, cagrilintide–semaglutide in obesity (New England Journal of Medicine, 2025). https://doi.org/10.1056/NEJMoa2502081
Frequently asked questions
Q: What is the difference between petrelintide and semaglutide?
A: Petrelintide is a long-acting amylin analogue that activates calcitonin receptor/RAMP complexes, while semaglutide is a GLP-1 receptor agonist. Both are dosed once weekly in trials, but they act on separate satiety pathways. Petrelintide is investigational; semaglutide is approved.
Q: Is petrelintide more effective than semaglutide for weight loss?
A: No head-to-head trial has been published. Phase 2 ZUPREME-1 reported up to 10.7% weight loss at 42 weeks with petrelintide, and STEP 1 reported 14.9% at 68 weeks with semaglutide 2.4 mg. Differences in trial length, population and dose escalation make the comparison indirect.
Q: Does petrelintide cause less nausea than semaglutide?
A: That is the central research hypothesis for amylin analogues. In ZUPREME-1, GI adverse events in the maximally effective arm were reported as similar to placebo, with no vomiting. A direct comparative trial would be needed to confirm a tolerability difference.
Q: Can petrelintide be combined with a GLP-1 agonist?
A: It was engineered for stability at neutral pH so it can be co-formulated with other peptides. A Phase 2 trial (NCT07589686) is evaluating petrelintide with Roche's GLP-1/GIP agonist enicepatide, following the precedent of the cagrilintide–semaglutide combination studied in REDEFINE 1.
Q: When could petrelintide be approved?
A: The Phase 3a ZUPREME programme began on September 22, 2026, with a 64-week primary endpoint. Regulatory submissions would typically follow completion of those trials, so approval is not expected before the late 2020s.
See also:
- Petrelintide vs Cagrilintide: Two Long-Acting Amylin Analogues Compared: how petrelintide compares with the amylin component of CagriSema
- Cagrilintide vs Semaglutide: the other amylin-versus-GLP-1 pairing, with REDEFINE combination data
- Petrelintide vs Eloralintide: the Zealand/Roche and Lilly amylin programmes side by side
For laboratory research purposes only. Not for human or animal consumption. Compounds described are not approved by the FDA for human or veterinary use unless explicitly stated.