Cagrilintide vs Petrelintide
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: AM833, NN9838
Cagrilintide (also called AM833) is a long-acting synthetic analog of amylin, the gut-brain satiety hormone co-secreted with insulin by pancreatic beta cells. It is an investigational once-weekly injectable being developed by Novo Nordisk for obesity, most prominently as the amylin half of CagriSema (cagrilintide plus semaglutide). It is not yet approved as a standalone drug, but it has cleared phase 2 trials and is in late-stage development.
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 | Cagrilintide | 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 | Cagrilintide is a non-selective agonist of the amylin and calcitonin receptor family. It activates amylin receptors (which are calcitonin receptors paired with RAMP accessory proteins) to signal satiety in the brain, slow gastric emptying, and blunt the post-meal glucagon rise. Mechanistic work in mice shows it reduces body weight mainly through amylin receptors AMY1R and AMY3R acting in the hindbrain, with the area postrema as a key entry point and downstream signaling through the nucleus of the solitary tract and parabrachial nucleus. Notably, weight loss in those studies persisted even after the acute appetite-suppressing effect faded, hinting at effects on energy balance beyond simple food-intake reduction. Chemically it is built on a pramlintide-like 37-amino-acid backbone with substitutions and a fatty-diacid chain attached to extend its half-life to roughly a week, enabling once-weekly dosing. | 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 | 2.4 mg weekly Once weekly | Not publicly disclosed (once-weekly trial doses) Once weekly |
| Administration | Subcutaneous injection once weekly | Subcutaneous injection once weekly |
| Typical Duration | Long-term / chronic use expected | 16 weeks (phase 1b) to 42 weeks (phase 2) in completed trials |
| Best Time to Take | Any consistent time weekly | Same day each week |
Possible Side Effects May vary by individual |
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| Research Summary | Cagrilintide has real human data, which sets it apart from most peptides in this category. In a 2021 Lancet phase 2 dose-finding trial (Lau et al.), once-weekly cagrilintide at 4.5 mg produced about 10.8% mean body weight loss over 26 weeks, beating both placebo (around 3%) and liraglutide 3.0 mg (around 9%), establishing that amylin agonism alone can drive clinically meaningful weight loss. Its bigger story is combination therapy: paired with semaglutide as CagriSema, it advanced into phase 3 REDEFINE trials for obesity and type 2 diabetes, with reported weight loss in the low 20% range, though final results came in somewhat below the most optimistic expectations. Side effects are dominated by the expected gastrointestinal effects (nausea, vomiting) common to gut-hormone drugs. As of 2026 cagrilintide is investigational and not FDA-approved on its own. The evidence is genuinely human and well-controlled here, which is rare, but it is still a drug under regulatory review rather than an approved therapy. | 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: Cagrilintide vs Petrelintide
What is the difference between Cagrilintide and Petrelintide?
Cagrilintide is a weight loss peptide that cagrilintide (also called am833) is a long-acting synthetic analog of amylin, the gut-brain satiety hormone co-secreted with insulin by pancreatic beta cells. it is an investigational once-weekly injectable being developed by novo nordisk for obesity, most prominently as the amylin half of cagrisema (cagrilintide plus semaglutide). it is not yet approved as a standalone drug, but it has cleared phase 2 trials and is in late-stage development. 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, Cagrilintide or Petrelintide?
Neither is universally "better" - the choice depends on your specific goals. Cagrilintide 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 Cagrilintide and Petrelintide be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using Cagrilintide 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.