AOD-9604 vs Petrelintide
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: Anti-Obesity Drug 9604, Tyr-hGH Fragment 177-191
AOD-9604 is a synthetic fragment of human growth hormone: residues 177 to 191 of the hormone with an extra tyrosine added at the front, 16 amino acids in total. The idea was to keep the fat-burning end of growth hormone while leaving out the part that raises IGF-1 or messes with blood sugar. It was developed by Metabolic Pharmaceuticals in Australia and tested as an anti-obesity drug, but it is not approved by the FDA or any major regulator, development stopped after its big Phase IIb trial missed its weight-loss target, and it is banned in sport by WADA.
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 | AOD-9604 | 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 | In lab and animal studies, AOD-9604 appears to nudge fat cells toward breaking down stored fat (lipolysis) and away from making new fat (lipogenesis), echoing the lipolytic tail-end of the full growth hormone molecule. Unlike real growth hormone, it does this without meaningfully raising IGF-1, the downstream growth signal that drives growth hormone's anabolic and blood-sugar effects. The exact receptor it works through is not pinned down, and a clean, growth-hormone-receptor-independent pathway remains a working hypothesis rather than settled science. In short, the proposed selling point is fat-burning signaling without the classic growth hormone baggage, but the molecular details are still fuzzy. | 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 | 300 mcg daily Once daily, usually morning, fasted | Not publicly disclosed (once-weekly trial doses) Once weekly |
| Administration | Subcutaneous injection or oral (studied both) | Subcutaneous injection once weekly |
| Typical Duration | 12-24 weeks in studies | 16 weeks (phase 1b) to 42 weeks (phase 2) in completed trials |
| Best Time to Take | Morning (fasted) | Same day each week |
Possible Side Effects May vary by individual |
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| Research Summary | The animal and cell data look encouraging, but the human story is where it falls apart. Across roughly six randomized, double-blind, placebo-controlled trials involving about 900 people, a safety review published in the Journal of Endocrinology and Metabolism (Moré et al.) found AOD-9604 was well tolerated, did not raise IGF-1, did not harm glucose metabolism, and triggered no detectable antibodies. The catch: it did not deliver clinically meaningful weight loss. The largest trial, a 24-week Phase IIb study in several hundred obese adults, failed to beat placebo on weight loss, and Metabolic Pharmaceuticals dropped obesity development around 2007. So the honest summary is a peptide with a clean safety record in humans and essentially no proven efficacy for fat loss in humans. | 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: AOD-9604 vs Petrelintide
What is the difference between AOD-9604 and Petrelintide?
AOD-9604 is a weight loss peptide that aod-9604 is a synthetic fragment of human growth hormone: residues 177 to 191 of the hormone with an extra tyrosine added at the front, 16 amino acids in total. the idea was to keep the fat-burning end of growth hormone while leaving out the part that raises igf-1 or messes with blood sugar. it was developed by metabolic pharmaceuticals in australia and tested as an anti-obesity drug, but it is not approved by the fda or any major regulator, development stopped after its big phase iib trial missed its weight-loss target, and it is banned in sport by wada. 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, AOD-9604 or Petrelintide?
Neither is universally "better" - the choice depends on your specific goals. AOD-9604 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 AOD-9604 and Petrelintide be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using AOD-9604 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.