Retatrutide (GLP-3)

Right here. Lumen Research sells GLP-3 retatrutide for research use in 10mg and 20mg vials, shipped from San Antonio, Texas. Orders placed before 12PM ET ship the same business day, Monday through Saturday, and US orders over $200 ship free.

Yes. Every lot is third-party tested by Freedom Diagnostics (USA), with identity confirmed by LC-MS: the two 10mg lots at 99.76% (lot 590B4F2) and 99.91% (lot RT10-2610) and the 20mg lot at 99.91%, all HPLC-UV purity. Each full Certificate of Analysis is further down this page.

"GLP-3" is an informal nickname rather than a formal classification. Retatrutide acts on three receptors — GLP-1, GIP and glucagon — where tirzepatide acts on two, so the research community started calling it the next step along from GLP-1. The compound's actual designation is LY3437943.

Tirzepatide is a dual GIP/GLP-1 receptor agonist. Retatrutide adds glucagon-receptor activity to those two. We keep a side-by-side write-up of what the published research examined for each in our tirzepatide vs retatrutide comparison.

Its receptor pharmacology was characterised in Coskun et al., Cell Metabolism 2022, and it was examined in Phase 2 trials in adults with obesity (Jastreboff et al., NEJM 2023) and with type 2 diabetes (Rosenstock et al., Lancet 2023), followed by Phase 3 trials published in 2026 (TRIUMPH-1, NEJM; TRIUMPH-2, Lancet). Gastrointestinal events were the most commonly reported adverse findings. Our retatrutide research guide summarizes what each study measured.

Both vials contain the same compound and differ only in the quantity of lyophilized powder. The 20mg vial is the lower cost per milligram. The two sizes come from separately tested lots, so the purity figure for each is in the lab-testing answer above and on its own certificate below.

Credit and debit card, Apple Pay, Google Pay, Zelle and Cash App. Choosing the card option places the order first, then gives you a secure payment link on your order confirmation and in your order email; that link also accepts Apple Pay and Google Pay. Zelle orders receive a 5% discount, applied automatically at checkout.

Orders placed before 12:00 PM ET on a business day are dispatched the same day, Monday through Saturday. Standard US shipping is a $15 flat rate and orders over $200 ship free. Inside San Antonio we also deliver to your door in the evening, or you can meet us and collect free of charge.

Lyophilized powder keeps at −20 °C for long-term storage or 2–8 °C short-term. Once reconstituted with bacteriostatic water, refrigerate at 2–8 °C and keep it out of light. Our reconstitution guide covers the full process.