Retatrutide is an investigational drug, not an FDA-approved product, and Eli Lilly says it "cannot be legally sold or marketed for human use." Six of the eight vendors we rate still list research-labeled retatrutide; on October 7, 2026, PSPeptides posted the most complete lot-matched testing and American Peptides, our #1 overall pick, had lot-matched COAs for every size but named no lab.
Notice: Research peptides are sold for in-vitro laboratory research only. They are not FDA-approved, not for human or animal consumption, and this page is not medical advice.
This page covers prices and certificates only. It has no dosing, protocol or human-use content, by our policy. Our criterion: a retatrutide certificate that names the lab and the lot beats a "third-party tested" badge. We don't test products; we check what each vendor publishes.
What retatrutide is, and its status in October 2026
Retatrutide (Lilly code LY3437943) is a single peptide that acts on three receptors: GIP, GLP-1 and glucagon. Lilly calls it "an investigational, once-weekly, triple hormone receptor agonist" (Lilly, May 2026).
- Trials: Lilly has reported several phase 3 readouts since December 2025 (Lilly, July 2026). The latest, on September 29, 2026, came from a phase 3 study in type 2 diabetes (Lilly), which ClinicalTrials.gov lists as NCT05929079, completed, with LY3437943 as the study drug.
- Approval: none. In that release Lilly says retatrutide "cannot be legally sold or marketed for human use" and that it plans to submit it to FDA in the first quarter of 2027. Drugs.com also lists it as not approved.
- Access: outside trials, Lilly opened a limited early-access program for patients who meet strict medical criteria in August 2026 (FOX 35). That's the authentic drug under medical supervision, not a research-chemical sale.
Trial safety data is summarized in retatrutide side effects. None of it applies to research-labeled vials.
Regulatory section: what FDA and Lilly have said
- No compounding. FDA's GLP-1 page (current as of October 1, 2026) says "Retatrutide and cagrilintide cannot be used in compounding under federal law" and that they "have not been found safe and effective for any condition" (FDA).
- "Research" labels. The same page says FDA has warned companies selling retatrutide and other GLP-1-class drugs "falsely labeled 'for research purposes' or 'not for human consumption'."
- Warning letters. FDA's December 2024 letter to Swisschems named its retatrutide product. The August 24, 2026 Peptide Partners letter listed "GLP-3 Reta (Retatrutide)" as an unapproved new drug, despite the seller's "for research use only" labels.
- Lilly lawsuits. On August 12, 2026, Lilly filed six suits against four research-use sellers, a med spa and a compounding pharmacy, saying unregulated products "may be fake, impure, or mis-dosed" (Frier Levitt).
The full picture is in FDA peptide regulation in 2026 and our regulatory news log.
Retatrutide by vendor
Prices checked October 7, 2026, including any displayed sale price. $/mg is price divided by labeled mg. "With our code" is arithmetic, not a checkout quote, and we couldn't confirm whether codes stack with sale prices. Vendors appear in our editors' order.
| Vendor | Listed as | Price (size) | $/mg | With our code | Retatrutide COA evidence |
|---|
| American Peptides | RETA-GLP3 | $105 (10 mg); $89.25 Subscribe & Save | $10.50 / $8.93 | No code | Lot-matched PDFs for 10-60 mg (e.g. lot RETA10-0803); no lab named |
| NextGenPeps | GLP-RT | $71, was $89 (10 mg) | $7.10 | No code | Bioviridian, Sep 25, 2026, 99.72%; no lot shown |
| PSPeptides | Retatrutide | $39.99 (5 mg) to $229.99 (60 mg) | $8.00 to $3.83 | $62.99 for 10 mg with CHECKED ($6.30/mg) | Vanguard Laboratory, lot M09212026RT10, reported Sep 28, 2026, plus safety panel |
| Ascension Peptides | R-10, R-30 | $100, was $149.99 (10 mg); $250 (30 mg) | $10.00 / $8.33 | $50 for R-10 with AFFILIATE50OFF, first order ($5.00/mg) | Kovera Labs, batch 03-05260628, May 26, 2026 |
| Licensed Peptides | LP3-R | Login required | - | Affiliate5 (5% off) | Report images list lot V260616-7 for seven sizes |
| Alpha Pro Peptides | GLP-3 | $74.99 (10 mg); $169.99 (30 mg) | $7.50 / $5.67 | No code | Freedom Diagnostics, lot AP-RT10-0426, May 18, 2026 |
PSPeptides' full ladder: 5 mg $39.99, 10 mg $69.99, 15 mg $89.99, 20 mg $104.99, 30 mg $144.99, 40 mg $179.99, 50 mg $199.99, 60 mg $229.99. With CHECKED, the 60 mg vial works out to $206.99 ($3.45/mg), the lowest per-mg figure we found.
Peptide Plugs and Swiss Chems had no retatrutide listing on October 7, 2026.
Notes on each vendor's documentation
- American Peptides: the product page names the compound and its Lilly code in the title, though the product is called RETA-GLP3. Its COA page lists current and superseded lots for each size, but no lab, date or purity. The 10 mg PDF had no readable text naming a lab. Only the 10 mg price was shown. Review
- NextGenPeps: the GLP-RT page identifies it as "GLP-RT (LY3437943)." Its COA library has Bioviridian reports for 10 mg and 20 mg, plus a March 2026 Janoshik report for 50 mg. No lot numbers. Review
- PSPeptides: the product page links a current certificate plus endotoxin, sterility, heavy metals and fentanyl reports for every size. The 10 mg certificate is from Vanguard Laboratory and labels the sample "GLP-3," not retatrutide. The same page gives reconstitution volumes and per-dose examples, and its blog runs a retatrutide dosage guide. That's the kind of content FDA cites, and we count it against PSPeptides. Review
- Ascension Peptides: the R-10 page doesn't say what R-10 is. Only its certificate file names say "Retatrutide": a Kovera Labs report and an older MZ Biolabs one. R-30 has a matching Kovera report (batch 43-05260628). Review
- Licensed Peptides: its purity reports page lists LP3-R in 5-60 mg, and seven of eight sizes share lot V260616-7. Prices need a free account (research access). Review
- Alpha Pro Peptides: the GLP-3 10 mg page uses "Reta" in its SKU and showed "Buy 1 Get 1 Free" at $37.49 per vial ($3.75/mg), if the offer applies as shown. The certificate reports 99.58% and 11.94 mg against a 10 mg label. Its testing page shows a 50 mg lot ID that also appears under SS-31. Review
Why code names are a labeling concern
RETA-GLP3, GLP-RT, R-10, LP3-R and GLP-3 all refer to products their own pages or certificates tie to retatrutide. Code names don't change the legal analysis: FDA identified "GLP-3 Reta" by name in the Peptide Partners letter. They also make certificates harder to match to vials, so our method counts them against a vendor.
How to check a retatrutide COA
- Match the lot to the size. American Peptides and PSPeptides post one per size.
- Check the identity result and the sample name. A certificate labeled "GLP-3" should still confirm the right molecule by mass spectrometry.
- Compare measured mg with the label, since overfill like Alpha Pro's changes concentration math.
See how to read a peptide COA, peptide purity vs net content and the COA checklist.
Independent test data
Finnrick's retatrutide page lists 378 vendors and 4,367 tests. None of our eight vendors appeared in its public rows on October 7, 2026; ranks 9-20 require an account. Every certificate above was commissioned by the vendor. More: what is Finnrick?
Codes and vendor links
We have affiliate relationships with PSPeptides (CHECKED, 10% off), Ascension Peptides (AFFILIATE50OFF, 50% off a first order) and Licensed Peptides (Affiliate5, 5% off), and may earn a commission. See peptide coupon codes. In our editors' order:
Bottom line
For research retatrutide, PSPeptides posts the deepest testing and the lowest price per mg, but its dosing content is a labeling problem. American Peptides, our #1 overall pick, has lot-matched certificates for every size without naming the lab. Ascension's first-order code gives the lowest price on a 10 mg vial, if it applies to the sale price. Every listing here is an unapproved, research-labeled product that FDA and Lilly are actively pursuing in the market. Prices for other compounds are on our homepage shelf, tirzepatide listings are compared in tirzepatide vendors, and the full ranking is at best peptide vendors in the USA.
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