What is Retatrutide?
Retatrutide, development code LY3437943, is a synthetic peptide that activates three hormone receptors at once: GIP, GLP-1 and glucagon. That makes it one of the most closely studied metabolic research peptides of recent years. This page explains its structure, how it works and how to handle it in the lab.
Structure and properties
Retatrutide is a single peptide of 39 amino acids built on a GIP-based backbone. A fatty-acid side chain lets it bind to albumin, which slows its clearance and gives it a half-life of around six days in clinical studies.
It is supplied as a lyophilised (freeze-dried) white powder. In this form it stays stable for a long time; it is reconstituted with bacteriostatic or sterile water before use in an experiment.
- Development code: LY3437943
- Class: GIP / GLP-1 / glucagon receptor triple agonist
- Length: 39 amino acids, lipidated
- Form: lyophilised powder in 15 mg and 20 mg vials
How retatrutide works: three receptors
GLP-1 and GIP are incretin hormones released by the gut after a meal; glucagon is produced by the pancreas. Earlier research peptides targeted one receptor (GLP-1) or two (GIP and GLP-1, as tirzepatide does). Retatrutide adds the glucagon receptor, which researchers study for its role in energy expenditure and liver fat metabolism.
Because of this triple mechanism, retatrutide is often called a 'triple agonist' or 'GGG agonist' in the scientific literature.
- GLP-1 receptor – incretin signalling, insulin secretion and appetite regulation
- GIP receptor – incretin signalling and fat metabolism
- Glucagon receptor – energy expenditure and hepatic metabolism
Research status
Retatrutide was developed by Eli Lilly. Phase 2 results in obesity and in type 2 diabetes were published in 2023 in The New England Journal of Medicine and The Lancet, and a large phase 3 programme (TRIUMPH) is under way.
Retatrutide is an investigational compound and is not an authorised medicine in the EU. The retatrutide sold by Virexa Labs is a research reagent intended exclusively for in-vitro laboratory research – not for human or veterinary use.
Retatrutide vs. tirzepatide
Both are lipidated peptides of 39 amino acids with a long half-life. Tirzepatide activates two receptors (GIP and GLP-1); retatrutide activates three (GIP, GLP-1 and glucagon). Researchers often study the two side by side to understand what the glucagon component adds.
- Tirzepatide (LY3298176): dual GIP/GLP-1 agonist
- Retatrutide (LY3437943): triple GIP/GLP-1/glucagon agonist
Storage and reconstitution
Store lyophilised vials at −20 °C, dry and protected from light; 2–8 °C is fine for short periods. After reconstitution with bacteriostatic water, keep the solution at 2–8 °C and use it within about four weeks. Avoid repeated freezing and thawing.
Our peptide calculator works out concentrations for you, and the storage guide describes the full procedure step by step.
Purity and quality at Virexa Labs
Every batch is tested by HPLC for ≥99% purity and by mass spectrometry for identity. The batch-specific Certificate of Analysis (COA) is published online on the product page and in our COA library.
Orders paid before 15:00 on working days ship the same day, in discreet packaging with tracking: 1–2 working days to Belgium, the Netherlands and Germany, 2–5 working days to Italy and Türkiye.
Metabolic research peptides
Frequently asked questions
Is retatrutide an approved medicine?
No. Retatrutide is an investigational compound in clinical development and is not authorised as a medicine in the EU. Virexa Labs supplies it only as a research reagent.
Is retatrutide intended for human use?
No. Our retatrutide is sold strictly for laboratory research and is not intended for human or veterinary use.
Which strengths are available?
15 mg and 20 mg vials of lyophilised powder, each with ≥99% HPLC purity.
What do I reconstitute retatrutide with?
Usually bacteriostatic water (0.9% benzyl alcohol), which we also sell. Add it slowly along the wall of the vial and swirl gently – don't shake.
How fast is delivery?
1–2 working days in Belgium, the Netherlands and Germany; 2–5 working days to Italy and Türkiye.