Peptide library
An evidence-led map of the peptide families behind today's weight-management and diabetes medicines, the approved medicines in each, the experimental candidates, and the research peptides people ask about. Molecular type is recorded separately from mechanism throughout: GLP-1 activity does not automatically make a drug a peptide.
About this library. Written by the GLPInfo editorial team with AI assistance from the official sources linked on the page, and approved by the site owner before publication. It has not yet been reviewed by a named clinician. Published 13 Sep 2026. Information, not medical advice: decisions about any medicine sit with you and a qualified prescriber. Spotted an error? Report a correction.
GLP-1 receptor agonists
Molecular type: Peptides (and one small molecule)
Medicines that activate the receptor for glucagon-like peptide-1, a gut hormone released after eating. Activation slows stomach emptying, increases insulin release when glucose is high and reduces appetite. Semaglutide, liraglutide and dulaglutide are peptides: modified versions of the natural hormone built to last longer in the body. Orforglipron activates the same receptor but is a small molecule taken as a tablet; it belongs to this family by mechanism, not by chemistry.
Evidence. Approved medicines in this family have large randomised trials for type 2 diabetes and weight management, and semaglutide has a cardiovascular outcomes trial (SELECT) behind its 2024 indications. See each profile for the verified regulatory record.
Medicines: Semaglutide 路 Liraglutide 路 Dulaglutide 路 Orforglipron
Dual and triple incretin agonists
Molecular type: Peptides
Single peptides engineered to act on more than one receptor. Tirzepatide activates GIP and GLP-1 receptors and is approved for diabetes and weight management. Retatrutide adds a third target, the glucagon receptor, and is investigational. Mazdutide (GLP-1 and glucagon) is being developed by Innovent in China under licence from Lilly; a programme there does not give it UK, US or EU status.
Evidence. Tirzepatide's approvals rest on the SURPASS and SURMOUNT trial programmes. Retatrutide's Phase 3 results are company-reported until published and reviewed.
Medicines: Tirzepatide 路 Retatrutide 路 Mazdutide
Amylin analogues and GLP-1 combinations
Molecular type: Peptides and combinations
Amylin is a hormone released with insulin that slows stomach emptying and signals fullness. Eloralintide is an investigational amylin receptor agonist. CagriSema pairs cagrilintide, an amylin analogue, with semaglutide in one injection. Amycretin is a single molecule designed to act on both amylin and GLP-1 receptors, in development as an injection and as a tablet; results are formulation-specific and must not be mixed up.
Evidence. No medicine in this family is approved in the UK, US or EU as of the last check. CagriSema is recorded as submitted to the FDA in December 2025 on the sponsor's statement.
Medicines: Eloralintide 路 Amycretin 路 CagriSema
Popularly discussed research peptides
Molecular type: Varies; identities checked individually
Compounds such as BPC-157 and products marketed as TB-500 are widely discussed online but are not approved medicines in the UK, US or EU. GLPInfo's evidence pages for them are planned for the next phase. Each will state the exact identity of the substance, what human evidence exists, and what is unknown. Popularity is not evidence, and GLPInfo does not cover sourcing, dosing or stacking of unapproved products.
Evidence. Planned. Nothing is published until the human evidence has been checked substance by substance.
What this library does not do
It does not recommend treatments, calculate doses, describe peptide "stacks" or point to sources of unapproved products. It explains what each substance is, what evidence exists and what is uncertain, so readers can have an informed conversation with a qualified prescriber.