How a claim degrades between the bench and the listing
Lot-level verification with a public report is a real and achievable thing. It exists in this market, on a minority of listings.
Independent testing
Page 2 of 27 of this archive, newest first.
When a better instrument changes the answer rather than the confidence
Calibration drift is real, unremarkable, and the reason serious laboratories run internal standards.
Independent analysis puts a Homopeptide retatrutide lot at 98.3%, against 97.3% on the certificate
The result is unremarkable. What the report omits is not.
How a claim degrades between the bench and the listing
Every step between the laboratory report and the product page removes information, and the badge is the last step.
The pyrogen question has a price, and it is not the price of a purity run
The absence of microbiological capability in this market is a commercial fact with a straightforward explanation, and it is worth understanding before blaming anybody for it.
VendorInvestigate result on a Nantong cagrilintide lot lands 4.0 points below the supplier’s figure
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Independent analysis puts a ERP orforglipron lot at 98.6%, against 97.6% on the certificate
The result is unremarkable. What the report omits is not.
Janoshik, Medutest, PeptideMeter, VendorInvestigate: a capability audit
Endotoxin is the more tractable of the two questions, and a kinetic chromogenic determination is neither slow nor exotic. It is simply not on the menu.
Independent analysis puts a FGP tirzepatide lot at 96.0%, against 93.3% on the certificate
The result is unremarkable. What the report omits is not.
A certificate is a snapshot, and peptides do not stand still
A document is only as good as the chain that connects it to the material, and most chains here are two or three links longer than the paperwork admits.
Janoshik result on a Hangzhou cagrilintide lot lands 0.9 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
The badge economy, and what it is actually certifying
Every step between the laboratory report and the product page removes information, and the badge is the last step.
Five things a purity figure cannot tell you
Aggregates dissociate in the mobile phase and are recorded as monomer. Only a size-based separation reports them.
We asked four laboratories for a sterility test. Here is what came back.
We asked all four services what they can determine, on what timescale, at what price, and under what accreditation. The answers are printed in full.
Independent analysis puts a TFC semaglutide lot at 96.7%, against 94.6% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
Same material, different gradients, different answers
Two years ago we ran an anonymised version of this comparison and promised a named one. This is it, with every method printed in full.
PeptideMeter result on a Changsha orforglipron lot lands 1.7 points below the supplier’s figure
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Independent analysis puts a MKM dulaglutide lot at 98.2%, against 96.7% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
VendorInvestigate result on a Zhuhai survodutide lot lands 4.2 points below the supplier’s figure
The supplier has not disputed the finding. It has not explained the gap either.
Same material, different gradients, different answers
The Journal submitted split samples from single lots to three assay services, under names unconnected to this publication, and published each method alongside each result.