Orforglipron vs AOD-9604.

Orforglipron (brand: Foundayo, development code LY3502970) is a once-daily, orally administered GLP-1 receptor agonist developed by Eli Lilly. The FDA approved it on 1 April 2026 for chronic weight management in adults with obesity, or overweight with at least one weight-related comorbidity, alongside a reduced-calorie diet and increased physical activity. It is included on this site despite not being a peptide: orforglipron is a small-molecule, non-peptide agonist of the same receptor the injectable GLP-1 peptides target, and it is the closest direct alternative to them, so leaving it out would misrepresent the landscape people are actually choosing between.

AOD-9604 ("Advanced Obesity Drug 9604") is a synthetic 16-amino-acid peptide corresponding to the C-terminal lipolytic region of human growth hormone (hGH), residues 177–191, with an added tyrosine at the N-terminus. It was engineered in the 1990s by researchers at Monash University and developed by the Australian biotech Metabolic Pharmaceuticals as an orally-investigated anti-obesity agent. The design goal was to isolate hGH's fat-mobilizing activity while leaving out the growth-promoting, IGF-1-stimulating actions of the full hormone.

Orforglipron binds and activates the GLP-1 receptor, the same class B G-protein-coupled receptor engaged by semaglutide, liraglutide and the GLP-1 arm of tirzepatide, producing glucose-dependent insulin secretion, slowed gastric emptying, suppressed glucagon and reduced appetite. The pharmacologically interesting part is how it does this without being a peptide. Work published in Science Translational Medicine (2024, PMID 39693407) characterises the basis for non-peptide agonism at this receptor: the molecule occupies a site that permits receptor activation from a small synthetic scaffold rather than mimicking the native hormone's full peptide sequence. Because it is not a peptide, it is not degraded in the gut the way oral peptide formulations are, which is why it can be taken as a conventional tablet with no food or water timing restrictions, unlike oral semaglutide.

In rodent models, AOD-9604 reproduces the lipolytic (fat-breakdown) and fat-oxidation–promoting effects of full-length growth hormone without binding the GH receptor and without raising IGF-1. Mechanistic work in obese and beta-3-adrenergic-receptor knockout mice indicated its effect on fat metabolism is associated with modulation of beta-3 adrenergic receptor activity and increased lipolysis and fat oxidation rather than classic GH-receptor signaling. Because it does not engage the GH receptor, it was hypothesized to avoid the insulin-resistance and tissue-growth liabilities of GH itself. Importantly, the cleanly receptor-independent, IGF-1-sparing profile is best characterized in animal and in-vitro work, not firmly established in humans.

Human evidence is substantial and spans phase 2 through phase 3 in both obesity and type 2 diabetes. A phase 2 trial in adults with obesity (NEJM 2023, PMID 37351564) established dose-dependent weight reduction, and a parallel phase 2 programme in type 2 diabetes reported in The Lancet (2023, PMID 37369232) showed reductions in HbA1c and body weight. Phase 3 results in obesity were published in the New England Journal of Medicine (2025, PMID 40960239), and a separate NEJM report (2025, PMID 40544435) covered early type 2 diabetes. A head-to-head trial against oral semaglutide in adults with type 2 diabetes appeared in The Lancet (2026, PMID 41765029), and a randomized phase 3 maintenance trial was published in Nature Medicine (2026, PMID 42120723). ACHIEVE-5, adding orforglipron to titrated insulin glargine, was reported in JAMA (2026, PMID 42251769). This is a considerably more complete human evidence package than almost anything else discussed in peptide communities, which is the point worth taking from it.

Preclinical evidence is the strongest part of the AOD-9604 record: chronic dosing reduced body-weight gain and increased fat oxidation in obese mice (Heffernan et al., Int J Obes, 2001; PMID 11673763). It progressed into human obesity trials in the early-mid 2000s; a 12-week randomized study reported only a modest separation from placebo (on the order of ~1–2 kg), and development was halted around 2007 after a larger ~24-week trial failed to show meaningful weight-loss efficacy, particularly once diet and exercise were standardized. No peer-reviewed pivotal trial demonstrates clinically useful weight loss, and there is no robust human evidence for the commonly marketed claims around cartilage, joint, or tendon repair: those rest on limited preclinical/early work. In short, the human data are negative-to-thin for obesity and largely absent for other indications.

The adverse-event profile reported across the trials is the familiar GLP-1 class pattern, dominated by gastrointestinal effects: nausea, vomiting, diarrhoea and constipation, generally most pronounced during dose escalation and often diminishing with time. Discontinuation for gastrointestinal reasons occurred in the trials. As an approved product it carries a prescribing label with the full contraindication and warning set for the GLP-1 receptor agonist class, and that label, not this page, is the authoritative safety document. Because it is a prescription medicine, safety monitoring happens through a prescriber rather than self-management, which is a meaningful difference from the research-use-only compounds elsewhere on this site.

Across the obesity trials, AOD-9604 was generally reported as well tolerated with a clean short-term safety signal, which is part of why it was later nominated for compounding review; however, these data come from time-limited studies and do not establish long-term safety. There is no established safety profile for chronic use, for injectable research-grade ("gray market") product, or for the unindicated cosmetic, joint, and anti-aging uses now marketed online. Purity, identity, and contamination of non-pharmaceutical material are real concerns, underscored by published forensic identification of illicit AOD9604 preparations (Drug Testing and Analysis, 2014; PMID 24976118). No dosing or administration guidance is provided here.

FDA-approved 1 April 2026 as Foundayo (orforglipron) for chronic weight management in adults with obesity, or with overweight plus at least one weight-related comorbid condition, in combination with a reduced-calorie diet and increased physical activity. It is a prescription medicine. Approval is indication-specific: an approval for chronic weight management is not a validation of any other use it may be marketed or discussed for. Regulatory status elsewhere in the world varies and should be checked locally.

AOD-9604 is not approved by the FDA (or any major regulator) for any therapeutic use; its obesity development program was discontinued, and it remains investigational/research-use-only. The FDA has evaluated it among nominated bulk drug substances for pharmacy compounding under section 503A and has flagged peptide candidates of this type as raising significant safety questions; it is also prohibited in sport and tested for by anti-doping authorities under the WADA framework.