Retatrutide vs Cagrilintide vs AOD-9604: Which Metabolic Peptide for Your Research Goal?
Retatrutide, Cagrilintide and AOD-9604 compared: mechanism, evidence and potency. The honest decision guide for metabolic research.
Three peptides, three completely different modes of action and three very different evidence classes. Retatrutide covers the full incretin plus glucagon cascade, Cagrilintide the Amylin satiety pathway, AOD-9604 a local lipolysis hypothesis. This guide helps with the choice and is honest about how well each substance is supported.
For the molecular pathways, see the GLP-1 agonist comparison and AOD-9604 vs Retatrutide. This page is about the decision.
TL;DR: The quick decision
Retatrutide: the most potent, best-supported. Triple agonist (GIP, GLP-1, Glucagon) with the largest published Phase 2 weight reduction. Cagrilintide: the Amylin satiety pathway, solid on its own and strong in combination (CagriSema), a different mechanism. AOD-9604: honestly the weakest. Local lipolysis hypothesis, but the human obesity trial was essentially negative and development was discontinued.
For research purposes only
This text classifies research peptides. It is not medical advice, not a recommendation for human use and does not replace consultation with a physician. Study doses and percentages cited here come from controlled clinical trials with titration and an accompanying program, no expected values and no dosing recommendation. None of these three substances is approved by the FDA or EMA.
Quick selection by research goal
Maximum potency and best evidence
Amylin satiety pathway, combination logic
Local lipolysis hypothesis (weakest evidence)
The three options in detail
Retatrutide: the most potent, best-supported
Retatrutide (LY3437943) is a single peptide that acts as a triple agonist at the GIP, GLP-1 and Glucagon receptor simultaneously [PMID 37366315, 37385280]. GLP-1 and GIP drive insulin secretion and central satiety, the additional Glucagon arm is the differentiator and is intended to increase energy expenditure and liver-fat mobilization.
In the Phase 2 obesity trial (double-blind, randomized, placebo-controlled, 338 adults without type 2 diabetes, 48 weeks), the 12 mg dose achieved a mean weight reduction of around 17.5% after 24 weeks and about 24.2% after 48 weeks [PMID 37366315], the largest reported reduction for a single agent of this class in a published Phase 2 obesity trial. A Phase 2 trial in type 2 diabetes additionally confirmed the glycemic effect [PMID 37385280].
Side effects were predominantly gastrointestinal and dose-dependent, plus a dose-dependent increase in heart rate [PMID 37366315]. Status: not approved, Phase 3 ongoing.
First-ever triple-action weight management peptide targeting three receptors at once: GLP-1, GIP, and glucagon. Shown exceptional results in Phase 2 trials - up to 24% weight reduction. The most advanced metabolic peptide available.
Cagrilintide: the Amylin pathway
Cagrilintide is a long-acting Amylin analogue (once weekly). Amylin is released together with insulin, signals satiety and slows gastric emptying. Cagrilintide acts as an Amylin and Calcitonin receptor agonist centrally on food intake; a 2025 paper showed the dependence on central Amylin receptors in an animal model [PMID 40609154]. This is a fundamentally different pathway than the incretin/glucagon axis.
In the Phase 2 monotherapy trial (706 adults, 26 weeks), weight reduction was about 6 to 10.8% depending on dose, versus around 3% on placebo [PMID 34798060]. It becomes stronger in the combination with Semaglutide (CagriSema): around 15 to 17% weight reduction versus Semaglutide alone [PMID 33894838, 37364590]. Side effects predominantly gastrointestinal. Status: not approved, in development.
Long-acting amylin analog studied for once-weekly satiety and appetite control. Phase 3 REDEFINE trials complete, NDA filed with FDA December 2025. A mechanism distinct from GLP-1 agonists.
AOD-9604: the lipolysis hypothesis with weak evidence
AOD-9604 is a synthetic fragment of human growth hormone (residues 176-191, the lipolytic domain). The hypothesis: it reproduces the fat-mobilizing effect of hGH without its unfavorable effects, that is, without an IGF-1 increase and without insulin resistance.
Honest assessment of AOD-9604
The mechanistic support is animal-based (studies in obese rats and mice) [PMID 11146367, 11713213]. The decisive human obesity trial was essentially negative: the early small signal did not hold up in the larger Phase 2b program, there was no statistically significant weight reduction versus placebo, and development was discontinued around 2007. AOD-9604 is therefore not in the same evidence class as the other two. Online claims of "significant fat loss" are refuted by the negative Phase 2b result.
Modified hGH fragment (176-191) studied for fat metabolism and lipolysis research. Interacts with beta-3 adrenergic receptors without growth-promoting effects.
Direct comparison at a glance
| Property | Retatrutide | Cagrilintide | AOD-9604 |
|---|---|---|---|
| Mechanism | Triple agonist GIP/GLP-1/Glucagon | Amylin analogue (satiety) | hGH fragment 176-191 (lipolysis hypothesis) |
| Best evidence | Phase 2 approx. 24% at 48 wk [37366315] | Phase 2 up to approx. 10.8%, CagriSema 15-17% [34798060, 37364590] | Human RCT negative [11146367 animal only] |
| Potency | Highest | Medium (strong in combination) | Weak/unsupported |
| Pathway | Incretin + Glucagon | Amylin | Local lipolysis (hypothesis) |
| Evidence class | Strong | Strong, often as combination | Weak, development discontinued |
| Status | Not approved, Phase 3 | Not approved, in development | Never approved as a drug |
Honest evidence ranking
From strong to weak: Retatrutide (largest published Phase 2 reduction, full incretin plus glucagon mechanics), then Cagrilintide (solid monotherapy and strong combination data as CagriSema, different Amylin pathway), lastly AOD-9604 (only animal-based mechanistics, negative human obesity trial, development discontinued). Marketing should not put AOD-9604 on the same level as the other two.
Which option fits which goal?
Maximum potency and best evidence
Retatrutide. Highest potency, largest published Phase 2 weight reduction, plus glycemic effect in the diabetes trial [PMID 37366315, 37385280].
Amylin satiety pathway or combination logic
Cagrilintide. A different mechanism than the incretins, solid on its own and especially strong in combination with Semaglutide (CagriSema) [PMID 34798060, 37364590].
Local lipolysis hypothesis, aware of the weak evidence
AOD-9604. Only if this specific hypothesis is to be investigated, with the honest assessment that human efficacy is not supported [PMID 11146367].
Frequently asked questions
The substances described here are research peptides. This article serves knowledge purposes only, is not medical advice and is not to be understood as a recommendation for human use.
Research context for English-speaking buyers
Most of our English-speaking customers ship to the UK, Ireland, Malta or other English-as-second-language EU territories. The regulatory picture differs per country.
- Relevant authorities
- MHRA (UK, post-Brexit), HPRA (Ireland, EU-aligned), FDA Section 503A bulks list (US, restricted Cat 2 status of several peptides as of 2026)
- Customs and VAT
- EU shipments include 19% VAT; UK shipments after Brexit are now extra-EU and may attract UK VAT plus a handling fee at import
- Typical shipping window
- EU 2-4 working days, UK 4-7 working days, other international 7-14 working days, depending on customs
Research-grade peptides shipped from our EU warehouse are sold for laboratory use only and are not authorised for human or veterinary therapeutic application in any of the destination jurisdictions. US customers should be aware that the FDA Section 503A bulks list classification (and the April 2026 reclassification of twelve compounds) only governs compounding pharmacies, not direct-to-researcher imports for non-clinical work. UK buyers should declare the consignment on import and may be asked for a research justification by HMRC. We provide a CoA per batch identified by colour code rather than serial number; customs sometimes asks for this document when clearing the parcel.