Peptides for metabolic & glp-1.
The one category where the evidence is genuinely strong, and where the gap between the approved drugs and everything else is enormous.
Metabolic peptides are the exception in this field. Where most research peptides rest on animal data, the incretin drugs have been through some of the largest and most rigorous obesity trials ever conducted, with tens of thousands of participants and hard cardiovascular outcomes measured over years. When people say peptides work, this is almost always the category they are actually pointing at, whether they know it or not.
The mechanism is a hormone the body already uses. GLP-1 is released by the gut after eating and drives insulin release, slows gastric emptying and reduces appetite through the brain. Natural GLP-1 is destroyed within minutes by the DPP-4 enzyme; the drugs are engineered versions that resist that breakdown and last for days. Newer agents stack additional receptors on top: GIP alongside GLP-1 in the dual agonists, and glucagon on top of both in the triple agonists, each addition aiming to add energy expenditure or liver benefit to the appetite effect.
That success has pulled a long tail of unproven compounds into the same category. Fragments of growth hormone marketed for fat loss, peptides designed to destroy fat tissue blood supply, and various metabolic research chemicals all get sold in the same breath as semaglutide. The evidence separating them is not subtle. One group has replicated Phase 3 outcomes and regulatory approval; the other frequently has no completed human trial at all.
The honest caveats on the approved drugs are worth stating clearly too. Weight returns for most people after stopping, which means these are treatments for a chronic condition rather than a course of therapy. Gastrointestinal side effects affect most users during dose escalation. And a meaningful share of the weight lost is lean mass, which is true of weight loss by most methods but still matters.
Approved incretin drugs are the best-evidenced compounds on this entire site. Almost everything else marketed for metabolic effect is not close, and the distance is measured in completed human trials, not marketing.
All GLP-1 drugs are basically the same.
They differ in which receptors they engage, how long they last, and how much evidence sits behind each indication. Related, not interchangeable.
Compounded versions are the same drug for less.
They are not the approved product, are not made to the same standard, and the trial evidence does not transfer to them.
Every compound in this category.
Graded on what has actually been published, with the regulatory reality on each one.
Adipotide (FTPP, also called prohibitin-targeting peptide-1) is an experimental chimeric peptidomimetic designed to destroy the blood supply of white fat rather than act as a hormone.
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.
Cagrilintide (development code AM833) is a long-acting, once-weekly synthetic analogue of the pancreatic hormone amylin, developed by Novo Nordisk.
CagriSema is a fixed-combination injectable investigational obesity therapeutic developed by Novo Nordisk that co-formulates two long-acting peptide analogues in a single once-weekly subcutaneous injection: cagrilintide, a long-acting amylin receptor agonist (analogue of the pancreatic hormone amylin), and semaglutide, a GLP-1 (glucagon-like peptide-1) receptor agonist already marketed for diabetes and obesity.
HGH Fragment 176-191 is a synthetic peptide corresponding to the final 16 amino acids (residues 176 to 191) of the C-terminal region of human growth hormone.
Liraglutide is a long-acting, injectable glucagon-like peptide-1 (GLP-1) receptor agonist, an acylated analog of the human incretin hormone GLP-1.
Mazdutide (IBI362, originally LY3305677) is an investigational once-weekly injectable dual agonist of the GLP-1 and glucagon receptors, based on a mammalian oxyntomodulin analog.
Retatrutide (development code LY3437943) is an investigational once-weekly injectable peptide developed by Eli Lilly for the treatment of obesity and related cardiometabolic disease.
Semaglutide is a long-acting glucagon-like peptide-1 (GLP-1) receptor agonist, an acylated, structurally modified analog of the native incretin hormone GLP-1, engineered for once-weekly (injectable) or daily (oral) dosing through albumin binding and resistance to DPP-4 degradation.
Survodutide (BI 456906) is an investigational once-weekly injectable peptide that activates two gut-hormone receptors at once: the glucagon receptor (GCGR) and the glucagon-like peptide-1 receptor (GLP-1R).
Tirzepatide (development code LY3298176) is a synthetic, 39-amino-acid modified peptide engineered as a "twincretin," a single molecule that activates two incretin hormone receptors at once.
Tracking one of these with your provider? PepCue handles the schedule, the vial math, and the record.