Amylin is widely seen as the most promising target in obesity medicine after GLP-1, and two companies are racing to prove an amylin analog can work as a standalone therapy rather than only as a partner drug. Petrelintide comes from Zealand Pharma with Roche; eloralintide comes from Eli Lilly.
They are pursuing the same target with different emphases. Eloralintide's Phase 2 data show larger weight loss at the top doses. Petrelintide's data show more modest weight loss with tolerability reported as close to placebo. Which matters more is genuinely unsettled — and it is the central question the amylin class has to answer.
At a glance
| Petrelintide | Eloralintide | |
|---|---|---|
| Developer | Zealand Pharma / Roche | Eli Lilly |
| Drug class | Long-acting amylin analog | Selective amylin receptor agonist |
| Phase 2 weight loss | Up to ~10.7% at 42 weeks (vs ~1.7% placebo) | ~9.5% to 20.1% by dose at 48 weeks (vs ~0.4% placebo) |
| Reported tolerability | Gastrointestinal effects close to placebo — the headline finding | Mild to moderate GI effects; placebo-like at lower doses |
| Development stage | Phase 3 endorsed; initiation planned H2 2026 | Phase 3 enrolling since late 2025 |
| Combination strategy | With Roche's dual GIP/GLP-1 agonist | With tirzepatide |
| Dosing | Once weekly (investigational) | Once weekly (investigational) |
| FDA status | Not approved | Not approved |
The bottom line
Bottom line: On raw weight loss, eloralintide's top doses are ahead — roughly 20% versus roughly 11%. On tolerability, petrelintide has the stronger claim, with gastrointestinal effects reported close to placebo. Neither is approved, both are in or entering Phase 3, and neither has the long-term data that decides these things. The interesting possibility is that both succeed in different niches: a high-efficacy amylin for maximum weight loss and a gentle one for people who cannot tolerate incretin drugs. Cross-trial comparisons like the numbers above are also inherently imprecise, since the studies differed in design, dose range, and duration.
Frequently asked questions
Which is better, petrelintide or eloralintide?
Neither has been tested against the other, so any comparison is indirect. Eloralintide produced more weight loss at its top doses (about 20% versus about 11%), while petrelintide reported gastrointestinal tolerability close to placebo. They are optimizing for different things, and Phase 3 will tell more than Phase 2 can.
What is an amylin analog?
Amylin is a hormone released alongside insulin after meals that signals fullness through receptors in the brainstem. An amylin analog mimics it in a longer-lasting form, slowing gastric emptying and reducing food intake through a pathway separate from GLP-1.
Are amylin drugs better tolerated than GLP-1 drugs?
That is the hypothesis driving the class, and early trials are encouraging — but it is not established. Phase 2 trials enroll a few hundred selected participants for under a year, which cannot settle a tolerability question at population scale.
Can you buy petrelintide or eloralintide?
No. Both are investigational and available only in clinical trials. Neither has been reviewed by any regulator. Products sold under these names by research-chemical vendors are unregulated and of unverified identity.
References
Combined peer-reviewed sources from both peptide guides. Inclusion is not endorsement.
- Fischer Munch H, Just R, Mosolff Mathiesen J, et al. Development of Petrelintide: a Potent, Stable, Long-Acting Human Amylin Analogue. J Med Chem. 2025. Peer-reviewed study
- 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. Peer-reviewed study
- Bailey CJ, Flatt PR, Conlon JM. Long-acting amylin-related peptides as therapies for obesity and type 2 diabetes. Peptides. 2026. Peer-reviewed study
- 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. Peer-reviewed study
- Briere DA, Qu H, Lansu K, et al. Eloralintide (LY3841136), a novel amylin receptor agonist for the treatment of obesity: From discovery to clinical proof of concept. Mol Metab. 2025. Peer-reviewed study
- Bhattachar S, Tham LS, Tidemann-Miller B, et al. Eloralintide, a selective, long-acting amylin receptor agonist for treatment of obesity: Phase 1 proof of concept. Diabetes Obes Metab. 2026. Peer-reviewed study