Where to Buy Retatrutide for Research (2026 Sourcing Guide)

Research-grade retatrutide (LY3437943) is sold as a lyophilized research reagent labeled "not for human or animal use." When sourcing it, verify >99% HPLC purity with a lot-specific Certificate of Analysis, confirm sealed glass-vial packaging, and choose a supplier that ships tracked to your region. Retatrutide is not an approved drug.

What "research-grade retatrutide" actually means

Retatrutide (LY3437943) is a triple GLP-1/GIP/glucagon agonist developed by Eli Lilly and published in the New England Journal of Medicine in 2023. Outside of regulated clinical trials it is available only as a research reagent — lyophilized powder in a sealed vial, labeled "not for human or animal use." It is not an FDA-approved medicine. Anyone designing a human study must source GMP material through the appropriate regulatory pathway; research-grade retatrutide does not belong in that workflow.

The four checks before you buy

Purity: >99% by HPLC, ideally cross-verified by mass spectrometry. Below 98% means meaningful contamination by truncated sequences.
Certificate of Analysis: lot-specific, with a batch number that matches the vial. A reputable lab name on the COA is a good signal.
Packaging integrity: nitrogen-flushed lyophilization, intact crimp seal, clean lyophilization cake.
Shipping & support: tracked dispatch to your region (USA/UK/EU) and a real contact channel for COA requests.

Red flags to avoid

Walk away from suppliers that cannot produce a lot-specific COA, that quote "pharmaceutical grade" for a research reagent, that promise human-dosing instructions, or that have no traceable batch numbering. Price that looks far below the market usually signals underdosed or low-purity material.

Why interest spiked in 2026

Sourcing questions surged this year for a reason. Retatrutide’s Phase 3 TRIUMPH-1 readout (May 2026) landed at the same moment the FDA moved to close large-scale GLP-1 compounding, while the molecule itself stays years from a pharmacy. If you are weighing it against the approved dual agonist, our retatrutide vs tirzepatide comparison lays out the mechanism and trial numbers; for coverage and price, see the NHS access and cost guide.

Where OXpeptides fits

We supply research-grade retatrutide at >99% HPLC purity, lyophilized in sealed vials, with a lot-specific COA on request and tracked worldwide shipping in plain packaging. For purity standards, reconstitution and storage across the whole catalog, see the complete research peptides guide. Buyers outside the English-speaking market may prefer the German-language documentation at peptide-kaufen.eu (DE).

Frequently asked questions

Is it legal to buy retatrutide for research?+

Retatrutide is sold as a research chemical labeled "for research use only, not for human or animal use" in the United States and most of the EU. It is not an FDA-approved drug. Buyers are responsible for compliance with their local regulations.

What purity should research-grade retatrutide have?+

Accept nothing below >98% by HPLC; serious suppliers document >99% and confirm identity with mass spectrometry. Ask for a lot-specific Certificate of Analysis that maps to the batch number printed on the vial.

How is retatrutide shipped and stored?+

Retatrutide ships as lyophilized powder in a sealed glass vial, stable at ambient temperature in transit. Store the sealed vial at -20 °C; after reconstitution with bacteriostatic water, keep at 2–8 °C and use within about 28 days.

What is the difference between retatrutide and tirzepatide?+

Tirzepatide is a dual GLP-1/GIP agonist; retatrutide adds glucagon-receptor activation, making it a triple agonist. In the NEJM 2023 Phase II trial the 12 mg retatrutide arm reached −24.2% bodyweight at 48 weeks. Both are studied as research compounds here, not sold for human use.

For research use only. Not for human or animal use. Not a drug. This article is sourcing and science information, not medical or dosing guidance.