HGH Fragment 176-191

AOD-9604 is a synthetic fragment of human growth hormone, copying just the last 15 amino acids of the hormone (residues 176 to 191) plus a tyrosine cap. 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, and development stopped after it missed its weight-loss targets.

Semaglutide is a GLP-1 receptor agonist, a peptide engineered to mimic the natural gut hormone GLP-1 but with a roughly week-long half-life so it can be dosed once weekly. It is FDA-approved and sold as Ozempic and Rybelsus for type 2 diabetes and as Wegovy for chronic weight management, with cardiovascular benefit also on the label. This is one of the most rigorously tested peptides in existence, backed by large randomized trials, so the evidence here is in a completely different league from research-only peptides.

Tirzepatide is a single peptide that activates two receptors at once: GIP and GLP-1, the two main incretin hormones your gut releases after eating. It is FDA-approved as Mounjaro for type 2 diabetes and as Zepbound for chronic weight management and obstructive sleep apnea, and it has produced the largest weight-loss numbers of any approved drug to date. Like semaglutide, this is a heavily trialed, fully approved medicine, not a gray-market research compound.

Retatrutide is the heavy hitter of the new weight-loss drugs: a once-weekly injectable peptide that hits three receptors at once - GIP, GLP-1, and glucagon - earning it the nickname triple-G agonist. In a phase 2 trial it produced some of the largest weight loss ever recorded for a drug, up to roughly 24 percent of body weight at the top dose. It is investigational, made by Eli Lilly, and not yet FDA approved as of 2026.

Orforglipron is Eli Lilly's oral, once-daily GLP-1 receptor agonist, and the headline is that it is a small molecule, not a peptide, so it survives the gut and can be taken as a plain pill with no food or water restrictions. It is being developed for type 2 diabetes and obesity and has completed multiple successful Phase 3 trials. As of mid-2026 it is filed for regulatory review but not yet approved.

CagriSema is a once-weekly injectable that pairs two drugs in one shot: semaglutide (a GLP-1 receptor agonist, the molecule behind Ozempic and Wegovy) and cagrilintide (a long-acting amylin analog). It is being developed by Novo Nordisk for obesity and type 2 diabetes, and in 2025 it cleared its phase 3 REDEFINE trials. It is not yet approved by the FDA, though regulatory filings are underway.