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.
Mainstream payment processors (Stripe, PayPal, the major card acquirers) classify research-chemical suppliers as high-risk and decline our category outright. UK Faster Payments via bank transfer settles in seconds, doesn't add card-processing fees to your order, and means no card data is stored. We're working on UK Open Banking integration.
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.