Independent analysis puts a QSC orforglipron lot at 97.3%, against 94.6% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
Nikolaj Brandvold
Page 4 of 7 of this archive, newest first.
Archive — page 4
123 piecesChoosing a needle for a subcutaneous peptide
A 4 mm needle at ninety degrees without a skin pinch is adequate for essentially all adults. The persistence of 12.7 mm needles in this market is habit, not reasoning.
PeptideMeter result on a Xi'an dulaglutide lot lands 2.6 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Independent analysis puts a MKM liraglutide lot at 96.2%, against 94.9% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Independent analysis puts a GGPeps retatrutide lot at 95.3%, against 92.8% on the certificate
The result is unremarkable. What the report omits is not.
A tested vial is evidence about a vial
A result on one vial generalises to a batch only if the vial was drawn in a way that makes it representative — and nobody records how it was drawn.
A few hundred participants carry the whole body-composition argument
A substudy powered to describe a mean is not a substudy powered to detect a clinically meaningful individual change.
PeptideMeter result on a Tianjin semaglutide lot lands 1.1 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Reproducibility, measured rather than assumed
Duplicate submissions under different names test within-laboratory repeatability, which is a different quantity from between-laboratory reproducibility.
Five lines that would change what a certificate is worth
A reader holding a certificate can work out what it does not cover in about ninety seconds, and that is a useful ninety seconds.
Independent analysis puts a WWB survodutide lot at 99.0%, against 97.4% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
What the outcome trials measured in the kidney
Asymptomatic pancreatic enzyme elevation is common on treatment and is not pancreatitis. The distinction is clinical, not biochemical.
Resolution, tailing, repeatability: the arithmetic before the result
System suitability is the set of checks demonstrating that the instrument and method were performing adequately when your sample was injected. It is recorded as a matter of…
Independent analysis puts a QSC exenatide lot at 97.5%, against 96.7% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
The change that weighs nothing at all
Deamidation adds 0.98 daltons. On a low-resolution instrument at incretin molecular weights, that is inside the noise.
Medutest result on a Hangzhou dulaglutide lot lands 3.0 points below the supplier’s figure
The result is unremarkable. What the report omits is not.
The arithmetic behind every identity confirmation, worked in full
A peptide has a monoisotopic mass and an average mass, they differ by several daltons at this molecular size, and a certificate that does not say which it quotes cannot be…
Why FGP can be entirely straightforward and still tell you nothing about bioburden
The Journal has read several hundred certificates from twenty companies. We set out what the documents actually cover, and what a reader is filling in from imagination.
HbA1c and its lag: what a result three months old is telling you
What the SURPASS and STEP programmes reported, with the estimands and the baseline values stated.
The badge is about a sample. The listing is about a product.
Lot-level verification with a public report is a real and achievable thing. It exists in this market, on a minority of listings.