February 2025

What the trials counted as intolerance

The ceiling varies severalfold between people, and nothing measurable at baseline predicts where it sits.

Holding the dose before surgery: for whom, for how long

A drug that delays gastric emptying complicates the assumption behind every fasting instruction in perioperative medicine. The…

Stepping down is part of titration

Every major phase 3 protocol in this class allowed escalation to be delayed for tolerability. Almost no product label explains…

The trade has decided the ceiling is arbitrary. The trials disagree.

Higher doses of these molecules have been studied. In general they produced modest additional efficacy and disproportionate…

What a month without the drug does to tolerability

The convention — resume lower, re-escalate — is not caution. It follows directly from the elimination half-life.

The steps get smaller as the ladder gets higher, and that is deliberate

What the published pharmacokinetics permit, what the labels state, and where the two diverge.

The glucagon receptor arm, and why it is the hardest to reason about

What adding GIP activity does, on the current evidence, and what remains unresolved.

How a peptide that lasts seven days binds a receptor that recycles in minutes

A tour of what happens in the thirty seconds after binding, and why it matters at week thirty.

Date of analysis, date of manufacture, and the gap between them

The interval between manufacture and analysis is the most under-read figure on the page, and the one most likely to matter by…

The anatomy of the most reproduced page in this trade

The header identifies the batch, the table records the tests, and the footer says who is answerable. Two of the three are…

Six words a verification badge would need to mean anything

Lot-level verification with a public report is a real and achievable thing. It exists in this market, on a minority of listings.

Why a dead-clean sterile filter can pass pyrogen straight through

The limit for a parenteral product is calculable from the dose and the body weight in two lines. Almost nobody in this trade…

The degradation product that elutes underneath the parent peak

An isoaspartate rearrangement changes the molecule and not the mass. A method that confirms identity by molecular weight alone…

What happens in solution that does not happen in the cake

Every degradation pathway accelerates by orders of magnitude on reconstitution, because the solvent that lyophilisation removed…

Six words a verification badge would need to mean anything

What a verification mark would have to carry to be checkable: a date, a lot, a method, a submitter and a link to the report.

Who signed this, and what did they undertake by signing it

What the Journal asks when a document arrives unsigned, and what the answers have been.

What the outcome trials measured in the kidney

Estimated glomerular filtration rate is a calculation with muscle mass in the denominator of its assumptions. In this population…

Every fortnight, every third week, seasonally: an unstudied practice

An absence of evidence is not evidence of harm. It is also not a licence.

The scale is not the measurement, and neither is the handheld device in the clinic

A body-composition report gives four decimal places and no confidence interval. That is the whole difficulty in one sentence.

A year after stopping: what the trials found at the far end

Fat mass, lean mass, and the composition of regained weight — the thinnest literature in this piece.

Which results are findings and which are consequences of the weight loss

Three different explanations for the same abnormal number, and how to tell them apart.

The precision question nobody puts to a body-composition report

A body-composition report gives four decimal places and no confidence interval. That is the whole difficulty in one sentence.

What the protein literature actually shows, and in whom it was shown

The denominator matters more than the ratio: per kilogram of body weight, of ideal weight, or of lean mass gives three different…

The advice is mostly reasonable. The certainty is not earned.

The gap between a defensible recommendation and a confident one is where most of the harm in this subject lives.

The change that weighs nothing at all

What would be needed to catch each of these, and what it would cost.

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…

What PeptideMeter charges to answer the pyrogen question

We submitted vials for endotoxin determination and report the results, the method and the laboratory, because a pyrogen figure…

Two documents, two disciplines: purity and sterility are not the same trade

Every certificate circulating in this market answers a question about molecules. Almost none answers a question about organisms,…

The badge economy, and what it is actually certifying

What a verification mark would have to carry to be checkable: a date, a lot, a method, a submitter and a link to the report.

Reproducibility, measured rather than assumed

Duplicate submissions under different names test within-laboratory repeatability, which is a different quantity from…

Why a dead-clean sterile filter can pass pyrogen straight through

The limit for a parenteral product is calculable from the dose and the body weight in two lines. Almost nobody in this trade…

What we would need to randomise to answer this properly

One randomised trial has combined a GLP-1 receptor agonist with supervised exercise. Its result is the single most useful piece…

What happens when the drug is taken away: three randomised answers

What was withdrawn, from whom, after how long, and what was measured afterwards.

Do you need the top of the ladder?

What the trials measured was continuation against withdrawal. What patients want to know is continuation at a lower dose, and…

The reference change value: the number that tells you whether a delta is real

A flag is a probability statement about a population. It is not a statement about the person holding the printout.

Maximum tolerated is not maximum approved

A plateau at an intermediate dose and a plateau at the maximum dose look identical from the outside and mean different things.

Why your laboratory interval differs from the one in the textbook

Two sources of noise sit under every number: how reproducible the assay is, and how much the analyte varies within the same…

Attribution is the hard part

Pancreatitis is rare, was adjudicated in the outcome programmes, and did not show the imbalance early case reports suggested.

Why people actually stop, in the order they actually stop

Why the reason for stopping changes what happens afterwards.

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.

How a claim degrades between the bench and the listing

What a verification mark would have to carry to be checkable: a date, a lot, a method, a submitter and a link to the report.

How a claim degrades between the bench and the listing

A badge asserts that something was tested. It does not assert what, when, on whose sample, by what method, or whether the lot on…

Side effects, cost, supply, target: four reasons with four trajectories

Why the reason for stopping changes what happens afterwards.

An interlaboratory comparison nobody had run

Duplicate submissions under different names test within-laboratory repeatability, which is a different quantity from…

What TRIUMPH-3 tells us about maintenance, and what it does not

Every withdrawal trial compared full dose against nothing. The clinically interesting comparison — full dose against a reduced…

Five things a purity figure cannot tell you

An orthogonal method separates on a different physical principle, so that species co-eluting in the first are likely to resolve…

A spectrum is a photograph of an ion, not of a molecule

The two ionisation techniques in general use produce different charge distributions, different adducts and different failure…

Deamidation, oxidation, and the two shifts worth memorising

What would be needed to catch each of these, and what it would cost.

Why Janoshik may run electrospray where another laboratory runs MALDI

The two ionisation techniques in general use produce different charge distributions, different adducts and different failure…

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.

Before anything is weighed, the peptide has to be charged

A brief and unromantic tour of the interface between a liquid sample and a vacuum.

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.

A number without a suitability record is a number from an unknown instrument

System suitability is the set of checks demonstrating that the instrument and method were performing adequately when your sample…

What a purity certificate is silent about

A purity figure is silent on peptide content, on water, on counter-ion, on sterility, on endotoxin and on stability. Each of…

Tolerability is the ceiling, and the ceiling is personal

Trial discontinuation figures are a floor, not an estimate: trial populations are supported in ways ordinary patients are not.

What the GLP-1 receptor actually does when tirzepatide binds it

The class is described as though every molecule in it did the same thing. At the receptor, they demonstrably do not.

Amylin is not an incretin, and cagrilintide is not a GLP-1 agonist

The glucagon arm raises energy expenditure and also raises hepatic glucose output. Balancing those is the whole engineering…

The dose you were told to reach and the dose you will actually stay on

The published ladder exists because a protocol needed a single number. Practice has never followed it exactly, and the…

Two decimal places on a single injection is a rhetorical choice

A result without a specification is a number. A specification without a result is a promise. Certificates in this market…

One measurement, twenty companies, forty compounds

A market that competes on one measurement will optimise that measurement. There are legitimate ways to raise a purity figure…