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 →
35 PEPTIDES · 12 CLASSES · 45 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.
LONG FORM
All 52 guides →Guides
LITERACY
How to read Highlights of Prescribing Information: the half-page front of an FDA label, line by line
Every modern FDA prescription label opens with a box of dense, bold, bulleted text titled "HIGHLIGHTS OF PRESCRIBING INFORMATION." It is the most-read part of the label and the easiest to misread. Over the last several weeks GLPWiki has walked through the numbered sections of the Full Prescribing Information one at a time. This guide covers the part that sits in front of all of them: what 21 CFR 201.57(a) requires Highlights to contain, how to decode the title line, the "Initial U.S. Approval" year, the summarized Boxed Warning, Recent Major Changes and the revision date, and why Highlights is designed as a signpost rather than a substitute for the Full PI. Label-reading literacy only: no doses, no treatment recommendations, no medical advice.
12 MIN READ
LITERACY
How to read the Drug Abuse and Dependence section on peptide labels (Section 9): controlled-substance status, abuse vs misuse vs addiction, and why GLP-1 labels skip it
GLPWiki's how-to-read-fda-peptide-labeling hub maps the whole Prescribing Information, and our Day 44 guide covered Section 10 Overdosage. This companion explains the section that sits just before it: Section 9 Drug Abuse and Dependence. What 21 CFR 201.57(c)(10) requires in 9.1 Controlled Substance, 9.2 Abuse and 9.3 Dependence; how the DEA schedule symbol shows up on the Highlights title line; the precise label meanings of abuse, misuse, addiction, physical dependence and tolerance; and why current GLP-1 and most peptide labels have no Section 9 at all. Label-reading literacy only: no doses, no treatment recommendations, no medical advice.
12 MIN READ
LITERACY
How to read the Indications and Usage section on peptide labels (Section 1): the indication sentence, Limitations of Use, and what "approved for" really means
GLPWiki's how-to-read-fda-peptide-labeling hub maps the whole Prescribing Information, and our GLP-1 indication guides list which product carries which use. This companion goes one level deeper on Section 1 itself: what 21 CFR 201.57(c)(2) requires an indication to contain, how to read an indication sentence in parts, why 'adjunct to diet and exercise' and 'reduce the risk of' are deliberate wording, how Limitations of Use differ from contraindications and from off-label use, what accelerated-approval wording signals, and why a molecule name is never an indication. Label-reading literacy only: no doses, no treatment recommendations, no medical advice.
13 MIN READ
REFERENCE LIBRARY
View all 35 →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 CHECK
BPC-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.
COMPARISON
GH 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.