Institute Investigation

What’s Actually Inside Online Retatrutide? We Independently Tested Leading Sellers.

Retatrutide is not approved anywhere. It is also freely available from 11 sellers we tested. We bought 21 vials and sent them to laboratories.

The Peptide Institute Investigations Updated 15 min read

What’s Actually Inside Online Retatrutide? We Independently Tested Leading Sellers.

What we did

21 retatrutide products purchased anonymously from 11 sellers and independently tested.

Samples tested
21
Sellers
11
Met label claims
86%
Under-filled vials
0

below 95% of labelled content

Below stated purity
16

of 21 samples

Methodology How these samples were obtained and tested
  1. Sellers were identified from the Institute’s existing company index; no seller was told it was being sampled.
  2. Purchases were made through standard retail checkout at list price, with no discount codes or press arrangements.
  3. Identity was confirmed by LC-MS/MS against a certified retatrutide reference standard, the central question being whether the vial contained retatrutide at all.
  4. Purity was measured by reversed-phase HPLC with UV detection at 214nm.
  5. Labelled content was verified by quantitative amino acid analysis and reported as a percentage of claim.
  6. Results were shared with each company ahead of publication.
Measured content as a percentage of label claim % of claim
  • Apex Peptides 99.5%
  • Research Peptides Co. 99.6%
  • Verity Research Chemicals 98.7%
  • Lumen Research Supply 97.8%
  • PureSci Labs 100.1%
  • BioRegen Research 98.5%
  • Cardinal Metabolic Clinic 100.8%
  • NextGen Peptides 99.3%
  • Northwind Telehealth 99.1%
  • Helix Research Supply 100.4%
Retatrutide results by seller, ordered by Index Score™
CompanyIndex Score™SamplesAvg. purityAvg. content vs. labelOutcome
Apex Peptides 91398.3%99.5%All verified
Research Peptides Co. 90298.2%99.6%All verified
Verity Research Chemicals 90295.8%98.7%All verified
Lumen Research Supply 89199.3%97.8%All verified
PureSci Labs 89297.9%100.1%All verified
BioRegen Research 87298.7%98.5%All verified
Cardinal Metabolic Clinic 87193.7%100.8%All verified
NextGen Peptides 85298.9%99.3%All verified
Northwind Telehealth 84276.1%99.1%1 failed
Helix Research Supply 79284.3%100.4%1 failed
Vector Peptide Supply 70297.4%98.6%1 discrepancy

Content was accurate; the purity claims were not

Vials held what they said they held. 16 of 21 samples, though, measured below the purity figure printed on the label, the quieter of the two failures, and the more common one.

Identity was not the problem here

We expected substitution and largely did not find it. The failure mode in this category is quantity and purity, not counterfeit compound, which is a different problem requiring a different kind of vigilance.

Specimens behind this report

Each links to its full laboratory record, chromatograms, methodology, lot number and chain of custody.

Retatrutide is an investigational triple agonist, GIP, GLP-1 and glucagon, still working through phase 3 trials. It has not been approved by any regulator in any jurisdiction. It is also, as of this writing, available for purchase within about ninety seconds from a laptop, from 11 of the sellers indexed by this Institute.

That combination is the reason we ran this investigation. When a compound with genuinely striking trial data is years away from approval, demand arrives long before any legitimate supply exists to meet it. What fills that gap is the research-chemical channel, where nobody is obliged to tell you what is in the vial and almost nobody independently checks.

We purchased 21 retatrutide products across 11 sellers and tested them the same way we test everything: anonymous purchase, chain-of-custody transfer, HPLC purity, mass-spectrometry identity confirmation, and quantitative content analysis against the label claim.

Identity held up better than we expected. The compound sold as retatrutide was, in the overwhelming majority of cases, retatrutide. This is not a market flooded with mislabelled semaglutide, which was our leading hypothesis going in. Purity ranged from 58.2% to 99.7%, and 18 of 21 samples met their label claims on both purity and content.

Content accuracy held up well, and we will say so plainly rather than manufacture a concern: no sample measured below 95% of the labelled milligram amount. Where these products fell short, they fell short on purity, 16 of 21 came in under the figure their own label claimed. That matters less acutely than an under-filled vial, but it is still a label that is not true.

2 samples failed verification outright. We would caution against reading that as reassurance about the category. Retatrutide is expensive, sellers know it attracts scrutiny, and the sample sizes here are smaller than we would like.

The Institute takes no position on whether anyone should obtain an investigational compound outside a clinical trial. We do take a position on this: if a product is going to be sold, its label should be true, and someone independent should be checking. Every specimen behind this piece is published in full.

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