GLP-3Phase 3
Retatrutide
An investigational triple agonist widely nicknamed "GLP-3" online. There is no GLP-3 hormone or receptor — the name is a consumer shorthand for a molecule that hits three receptors at once.
Half-life ~6 daysRead →
34 PEPTIDES · 12 CLASSES · 43 SOURCES
GLPWikiThe encyclopedia of peptides
Incretins and the triple agonists people call GLP-3, plus repair peptides, growth-hormone secretagogues, melanocortins and the rest of the field. Every entry states the mechanism, the receptor targets, the evidence, and where it came from.
GLPWiki is an independent, citation-first educational reference. It sells nothing, links to no suppliers, carries no sponsored entries, and publishes no doses or protocols. It explains what a compound is and what has been measured — it is not medical advice.
DATASHEET · RETATRUTIDE
- Also called
- GLP-3
- Receptors
- GLP-1 + GIP + glucagon
- Half-life
- ~6 days
- Status
- Phase 3
GLP-3 is not a hormone or a receptor. It is a nickname for retatrutide, an investigational Eli Lilly triple agonist. Not approved by any regulator.
START HERE
What GLP-1 actually is
The incretin hormone behind semaglutide and liraglutide — receptor, mechanism, clinical landscape.
GLP-2, the intestinal sibling
Same precursor protein, entirely different receptor and job: growth and repair of the gut lining.
There is no GLP-3 hormone
Why the nickname attached itself to retatrutide, and what a triple agonist really does.
TOOLS
Open calculatorsPeptide calculators
Reconstitution maths without the guesswork: concentration, volume to draw, syringe units and doses per vial. Educational arithmetic only — not dosing guidance.
LONG FORM
All 12 guides →Guides
LITERACY
How to read a peptide Certificate of Analysis
A Certificate of Analysis is only useful if it is lot-specific, method-documented, and matched to the vial in your hand. This guide is a field-by-field checklist: what a COA is, what HPLC and mass spectrometry each answer, why purity is not content, and which red flags mean the paperwork is not doing its job.
14 MIN READ
LITERACYHow to Read a Peptide Vial Label
A vial sticker is not a Certificate of Analysis. This checklist covers the fields that matter on a peptide vial label—name, mass, lot, storage, and research-use statements—and how to check them against the COA and the listing before you treat the paperwork as describing the vial in your hand.
12 MIN READ
LITERACYApproved vs investigational peptides: how to tell the difference
The same amino-acid sequence name can appear as an FDA-approved medicine, as an investigational trial drug under an IND, or as research-use catalog material. This literacy guide explains what each status actually means, how to verify it, and which paperwork answers which question.
13 MIN READ
REFERENCE LIBRARY
View all 34 →Featured peptides
GLP-1Approved
Semaglutide
A once-weekly GLP-1 receptor agonist and the most widely prescribed drug in the class. Approved for type 2 diabetes, chronic weight management and cardiovascular risk reduction.
Half-life ~7 daysRead →
DUAL AGONISTApproved
Tirzepatide
The first approved dual incretin agonist, activating both the GIP and GLP-1 receptors. Approved for type 2 diabetes, chronic weight management and obstructive sleep apnoea in obesity.
Half-life ~5 daysRead →
LONG FORM
All articles →Deep dives
DEEP DIVE
Retatrutide, the peptide the internet calls GLP-3
Why a triple agonist picked up a nickname that does not describe a real hormone — and what its trial data actually show.
EVIDENCE CHECKBPC-157: separating the claims from the evidence
The most discussed repair peptide on the internet has an enormous animal literature and almost no human trials. Here is the honest state of play.
COMPARISONGH secretagogues compared: sermorelin, ipamorelin, CJC-1295, tesamorelin
Four peptides that all raise growth hormone, by three different mechanisms, with wildly different levels of evidence.
COMMON QUESTIONS
What people ask first
- Is GLP-3 a real hormone?
- No. There is no GLP-3 hormone or receptor. It is an informal nickname used online for retatrutide, an investigational triple agonist that activates the GLP-1, GIP and glucagon receptors at once.
- What is the difference between GLP-1 and GLP-2?
- Both are cleaved from the same proglucagon precursor, but they act on different receptors. GLP-1 drives insulin secretion and satiety; GLP-2 drives intestinal growth and absorption and is used in short bowel syndrome, not weight management.
- Why do dual and triple agonists produce more weight loss?
- Adding GIP and glucagon receptor activity recruits pathways GLP-1 alone does not reach — GIP appears to improve tolerability and adipose handling, while glucagon raises energy expenditure and mobilises hepatic fat.
- Where does the information here come from?
- Every entry cites primary sources: peer-reviewed trial publications and trial registry records. Figures are trial means under protocol conditions, not predictions for any individual.