Triple receptor agonist · LY3437943
A 39-amino-acid synthetic peptide acting at the GLP-1, GIP and glucagon receptors. Janoshik HPLC-verified. Vial or pen. Same-day UK dispatch. Real human reply on WhatsApp.
Retatrutide (development code LY3437943) is a 39-amino-acid synthetic peptide engineered as a triple agonist at three of the four principal incretin and glucagon-related receptors: GLP-1, GIP, and glucagon. It carries a C20 fatty-diacid acylation that enables strong albumin binding and a serum half-life of approximately 6 days, supporting the once-weekly administration cadence used in published Phase 2 research literature.
In the published Phase 2 research (Jastreboff et al., NEJM 2023), Retatrutide produced the largest body-weight outcomes of any single-compound incretin programme reported to date, distinguishing the triple-agonist class from dual agonists like Tirzepatide and single-target agonists like Semaglutide.
| Class | GLP-1 / GIP / glucagon triple receptor agonist (acylated peptide) |
| CAS number | 2381089-83-2 |
| Molecular weight | 4731.43 g/mol |
| Sequence length | 39 amino acids |
| Reported half-life | ~6 days (~144 hours) in published research |
| Stability (lyophilised) | 24+ months at 2–8 °C, sealed and protected from light |
| Stability (reconstituted) | ~30 days at 2–8 °C in bacteriostatic water |
| Receptor targets | GLP-1R, GIPR, GCGR |
| Primary citation | Jastreboff et al. 2023 (NEJM) |
The compound inside is identical: same Retatrutide, same Janoshik-verified batch, same purity. The vial is a clear glass vial of lyophilised powder that you reconstitute yourself with bacteriostatic water; the pen is the same compound pre-loaded into a research injector pen with a dose dial, ready to use. The pen costs £15 more than the equivalent vial (the refill-service charge for filling and assembling the pen).
If you ordered a vial: just order another vial at the normal vial price. Add bacteriostatic water (£6) only if you've also run low on it. We dispatch same-day on UK weekday orders before 2pm.
If you ordered a pen: order a refill cartridge at vial price + £15 (refill service). The cartridge slots straight into your existing pen, so you don't need to buy a new pen device every time. The maths is laid out for you in the calculator above.
Card or bank transfer, your choice. You message us on WhatsApp or email, we confirm stock, then we send you a secure card payment link (Stripe-style flow) or our UK bank details for a Faster Payments transfer. Nothing is charged until you're ready and stock is confirmed.
No. Retatrutide is supplied strictly as a research-grade reference reagent for in-vitro laboratory research only, the same legal frame as Sigma-Aldrich, Cayman Chemical or Tocris. We do not provide dosing guidance for humans, administration protocols, or any content relating to therapeutic use. Read the UK legality guide ›
Royal Mail outer is plain brown kraft cardboard with no branding visible from outside. Inside: your vial(s) in protective packaging, your printed Janoshik COA where applicable, ten insulin syringes for vial orders, four sterile alcohol prep wipes, and a small printed handling-and-reconstitution card on the inside of the lid. Nothing on the outside identifies the contents.