Last updated: June 2026 · Research use only
Short answer: Buy research retatrutide only from a vendor that publishes a batch-specific, independent-lab COA with ?96% HPLC purity (?99% excellent) and mass-spec identity, and that ships domestically from the U.S. Proxiva Labs carries it with a COA on every order, FDA-registered GMP U.S. manufacturing, and same-day shipping before 4 PM EST.
What to check before you buy retatrutide
- A batch COA you can read before buying — see How to Read a Peptide COA.
- HPLC ?96% (?99% excellent) with mass-spec identity.
- U.S. shipping and a stable vendor — especially important after the 2026 shutdowns of Science.bio and Peptide Sciences.
Buying from a verified source
- COA with every order, independent-lab tested (Vanguard) — published purity 99.63% HPLC; certificates at /test-results/.
- Same-day shipping before 4 PM EST (Mon–Sun), 2–3 business day delivery, plain-packaged and tracked. Free shipping over $150.
- FDA-registered, GMP-certified U.S. facilities.
See the full ranked comparison in our Best Research Peptide Vendors 2026 guide.
FAQ
What should I check on a retatrutide COA? Batch number, HPLC purity ?96% (?99% excellent), mass-spec identity confirmation, an independent lab name, and a date.
What purity does the COA show? Proxiva’s published independent-lab (Vanguard) COA shows 99.63% HPLC — see /test-results/.
Does it ship with a COA? Yes — Proxiva includes a COA with every order and publishes certificates at /test-results/.
Research-use-only disclaimer: This product is intended strictly for research and laboratory use only. It is not approved for human consumption, medical application, or diagnostic use.
All products are sold strictly for research purposes only. Not for human consumption.