Eloralintide vs Petrelintide
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: GSBR-1290, Structure GSBR-1290
Eloralintide (Eli Lilly code LY3841136) is an investigational, long-acting, selective amylin receptor agonist given as a once-weekly subcutaneous injection for obesity. Amylin is the satiety hormone your pancreas releases alongside insulin, and eloralintide is built to mimic it without the gut side effects that sink most appetite drugs. It is not approved anywhere yet, but it has cleared Phase 1 and a 263-person Phase 2 trial with weight loss up to roughly 20 percent, and Lilly has said it is moving into Phase 3.
Also: ZP8396
Petrelintide is a long-acting amylin analog from Zealand Pharma, co-developed with Roche, designed as a once-weekly injection for obesity. The pitch is gentler weight loss than GLP-1 drugs but with far less nausea and vomiting. Two phase 2 trials read out positively in 2026 (up to 10.7% weight loss at 42 weeks), and a roughly 7,000-person phase 3 program has started. It is not approved anywhere.
Key Comparison Insights
- Both peptides belong to the Weight Loss category, suggesting similar primary applications.
Detailed Comparison
| Attribute | Eloralintide | Petrelintide |
|---|---|---|
| Category | Weight Loss | Weight Loss |
| FDA Status | Not FDA Approved | Not FDA Approved |
| Clinical Status | Pre I II III IV FDA | Pre I II III IV FDA |
| Mechanism of Action | Amylin (also called IAPP) is a hormone co-secreted with insulin after you eat, and it tells your brain you are full and slows how fast your stomach empties. Eloralintide is engineered to selectively switch on the amylin receptor, which is the calcitonin receptor paired with a receptor-activity-modifying protein (RAMP), in appetite-control regions of the brainstem and hypothalamus. The result is reduced food intake and earlier satiety. The reason this class is interesting is that, unlike GLP-1 drugs such as semaglutide and tirzepatide, amylin agonists seem to drive weight loss with much less nausea and vomiting, which is what the eloralintide trials reported. Whether it preserves more lean mass than GLP-1 drugs is a real hypothesis being tested, not a settled fact. | Amylin is a hormone your pancreas releases alongside insulin after meals. It acts on the brainstem to make you feel full sooner, slows stomach emptying, and curbs glucagon after eating. Zealand says amylin signaling also helps restore sensitivity to leptin, the body's long-term fullness signal. Native amylin is unusable as a drug because it clumps into fibrils and lasts minutes, so petrelintide was engineered to stay stable at neutral pH, avoid fibril formation, and last a week. That stability also means it can be co-formulated with other peptides, which is why Roche plans to combine it with its own GLP-1/GIP drug. The theory is that amylin gives more of a natural fullness feeling than GLP-1 drugs do, with fewer GI side effects; the tolerability part looks real so far, the bigger-picture claims still need phase 3. |
| Common Dosing | 120-240mg once daily Once daily | Not publicly disclosed (once-weekly trial doses) Once weekly |
| Administration | Oral tablet | Subcutaneous injection once weekly |
| Typical Duration | 36 weeks in Phase 2 trials | 16 weeks (phase 1b) to 42 weeks (phase 2) in completed trials |
| Best Time to Take | - | Same day each week |
Possible Side Effects May vary by individual |
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| Research Summary | This is one of the few research peptides on this site with genuinely strong, recent human data. The Phase 1 proof-of-concept study (Eli Lilly, published 2026) randomized 100 adults with obesity across five ascending dose cohorts and reported dose-proportional pharmacokinetics and least-squares mean weight reductions of 2.6 to 11.3 percent by week 12, with notably low gastrointestinal side effects (nausea 8 percent, vomiting 4 percent). In November 2025 Lilly announced topline Phase 2 results in 263 adults with obesity or overweight: at 48 weeks all dose arms beat placebo, with mean weight loss from about 9.5 percent at the lowest dose up to 20.1 percent at 9 mg, versus 0.4 percent on placebo, plus improvements in waist circumference, blood pressure, lipids, and glycemic markers. The most common adverse events were mild-to-moderate nausea and fatigue. The honest caveat: full peer-reviewed Phase 2 data and any head-to-head against tirzepatide are still pending, and there are no long-term safety or cardiovascular outcome results yet because Phase 3 is only just beginning. So the early efficacy signal is impressive, but durability and long-term safety are unproven. | A 16-week phase 1b trial (48 people) reported up to 8.6% mean weight loss at the highest dose versus 1.7% on placebo, with no early plateau. The phase 2 ZUPREME-1 trial (493 people with obesity or overweight, mean BMI 37) reported in March 2026 up to 10.7% mean weight loss at 42 weeks versus 1.7% on placebo. That is clearly less than semaglutide or tirzepatide produce, but tolerability stood out: no vomiting at the maximally effective dose, and side-effect dropouts (4.8%) no higher than placebo (4.9%). ZUPREME-2 (220 people with obesity and type 2 diabetes) reported in October 2026: 7.4-9.2% weight loss at 28 weeks versus 2.0% on placebo, placebo-adjusted HbA1c drops of 0.61-0.88 points, and GI dropouts of 1.9% versus 1.7%. Roche and Zealand have started phase 3a (ZUPREME-3, -4 and -5, about 7,000 people in total, including a cardiovascular-disease population). Honest take: a well-tolerated, moderate-strength drug whose real value may be as a combination partner, and the full peer-reviewed phase 2 data are still pending. |
Frequently Asked Questions: Eloralintide vs Petrelintide
What is the difference between Eloralintide and Petrelintide?
Eloralintide is a weight loss peptide that eloralintide (eli lilly code ly3841136) is an investigational, long-acting, selective amylin receptor agonist given as a once-weekly subcutaneous injection for obesity. amylin is the satiety hormone your pancreas releases alongside insulin, and eloralintide is built to mimic it without the gut side effects that sink most appetite drugs. it is not approved anywhere yet, but it has cleared phase 1 and a 263-person phase 2 trial with weight loss up to roughly 20 percent, and lilly has said it is moving into phase 3. Petrelintide is a weight loss peptide that petrelintide is a long-acting amylin analog from zealand pharma, co-developed with roche, designed as a once-weekly injection for obesity. the pitch is gentler weight loss than glp-1 drugs but with far less nausea and vomiting. two phase 2 trials read out positively in 2026 (up to 10.7% weight loss at 42 weeks), and a roughly 7,000-person phase 3 program has started. it is not approved anywhere. The main differences lie in their mechanisms of action and clinical applications.
Which is better, Eloralintide or Petrelintide?
Neither is universally "better" - the choice depends on your specific goals. Eloralintide is typically used for weight loss purposes, while Petrelintide is used for weight loss. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can Eloralintide and Petrelintide be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using Eloralintide and Petrelintide together should only be considered under medical supervision, as both compounds have their own side effect profiles and potential interactions. Research on their combined use may be limited.