February 2026

The half-life question, answered properly

Half-life, accumulation ratio and time to steady state are three separate quantities, and confusing them produces most of the…

The limits of mechanism: why receptor data will not tell you who responds

Receptor pharmacology is strong on average effects and almost silent on individual variation. That gap is where most reader…

What the trial protocols permitted, and what the labels omitted

Nausea and gastric delay attenuate over weeks at an unchanged dose. That single physiological fact is the entire justification…

Target dose, effective dose, and the distance between them

The dose-response curve in this class flattens near its top. That has direct consequences for whether the final rung is worth…

Holding a dose is a decision, not a failure

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

The brainstem does most of the work

A tour of the tissues where the receptor is expressed, and what happens in each.

Beta-arrestin, cAMP, and the part of dulaglutide’s mechanism nobody quotes

The receptor is expressed in more tissues than the popular account allows, and that is the whole story.

What happens in solution that does not happen in the cake

We set out what is known, what is inferred and what is simply assumed about the fortnight after a vial is opened.

Janoshik, Medutest, PeptideMeter, VendorInvestigate: a capability audit

The absence of microbiological capability in this market is a commercial fact with a straightforward explanation, and it is…

Janoshik, Medutest, PeptideMeter, VendorInvestigate: a capability audit

Four independent services underpin confidence in this market. All four are competent at chemistry. Microbiology is a different…

What PeptideMeter charges to answer the pyrogen question

Bacterial endotoxin is a heat-stable lipopolysaccharide from the outer membrane of Gram-negative organisms. It survives…

The sample is not the batch

A result on one vial generalises to a batch only if the vial was drawn in a way that makes it representative — and nobody…

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

A manufacturer’s certificate is a self-declaration. An accredited laboratory’s report is a third-party measurement. The trade…

Why a result on one vial says less than the trade needs it to

The condition on arrival is recorded by some services and not others, and it is one of the more informative lines in a report.

Bone density during rapid weight loss: what is known, which is less than you would hope

The evidence base is one secondary analysis, several small studies and a large amount of extrapolation from bariatric surgery.

Why "muscle-sparing" is a marketing term and not a measurement

Almost every practical recommendation in circulation was established in a population that does not resemble the people now…

Measuring more frequently generates more flags and not more information

What the pivotal programmes measured and how often, which is a more defensible template than most published monitoring schedules.

Sarcopenia is a diagnosis, not a synonym for losing lean mass

The rule that a quarter of weight lost is lean tissue has been in textbooks for decades and does not survive close reading.

Vitamin D, adiposity, and a volume-of-distribution problem

What the trials measured, which in the case of micronutrients is very little.

Coming off: what the pharmacology permits

What a slow reduction could plausibly buy, and what it certainly cannot prevent.

What the older diet-and-exercise trials found in the hip

The evidence base is one secondary analysis, several small studies and a large amount of extrapolation from bariatric surgery.

An interlaboratory comparison nobody had run

The Journal submitted split samples from single lots to three assay services, under names unconnected to this publication, and…

Low endotoxin recovery: the interference nobody looks for

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

Quadrupole, time-of-flight, orbital trap: what each class can and cannot see

Calibration drift is real, unremarkable, and the reason serious laboratories run internal standards.

The badge is about a sample. The listing is about a product.

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

A certificate is a snapshot, and peptides do not stand still

What happens to traceability when bulk material is subdivided, repackaged and relabelled two or three times before sale.

Freezing a reconstituted vial: the ice-water interface problem

An in-use period is established by a dedicated study on a specific formulation in a specific container at a specific…

What Medutest 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…

The badge economy, and what it is actually certifying

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

A guide to the results that will resolve themselves

A substantial proportion of the abnormal results generated during rapid weight loss are consequences of the weight loss rather…

What STEP 4 and SURMOUNT-4 actually established

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

What the survodutide schedule assumes about a person it has never met

We work the arithmetic out in full, because it is arithmetic and it is short.

The convention nobody explains before handing over the vial

A unit is a volume. A dose is a mass. The bridge between them is concentration, and concentration is a number somebody has to…

Why "muscle-sparing" is a marketing term and not a measurement

Grading six widely repeated claims against the studies actually behind them.

Why people actually stop, in the order they actually stop

The trials studied planned withdrawal. Almost nobody stops that way.

Load, not cardio: the distinction the general advice keeps losing

What was supervised, at what frequency, at what intensity, and for how long.

Why people actually stop, in the order they actually stop

Real-world persistence figures, with their definitions stated, because the definitions are doing most of the work.

Chain of custody, and where it begins

Chain of custody, in a regulated setting, begins at sampling. Here it begins when the package arrives.

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

The trials studied planned withdrawal. Almost nobody stops that way.

An interlaboratory comparison nobody had run

The Journal submitted split samples from single lots to three assay services, under names unconnected to this publication, and…

The shortage years, and what they taught about interruption

Why the reason for stopping changes what happens afterwards.

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

The commonest real-world strategy in this drug class is the least studied one.

The withdrawal trials, read as designs rather than warnings

Three randomised withdrawal designs have tested what happens when treatment stops. Their results are consistent and they are…

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…

Sterility is not a percentage, which is the whole difficulty

Purity, content, identity, sterility and endotoxin are five separate determinations. A single sheet of paper carrying one of…

Why SSA 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…

Counter-ion, water, salt: three masses with no chromatogram

Aggregates dissociate in the mobile phase and are recorded as monomer. Only a size-based separation reports them.

What the older diet-and-exercise trials found in the hip

The evidence base is one secondary analysis, several small studies and a large amount of extrapolation from bariatric surgery.

Monitoring intervals, and the case against measuring too often

Every additional analyte raises the probability of a flagged result and lowers the average information content of the panel.

Percentage of loss, absolute kilograms, and the sleight of hand between them

Both the reassuring reading and the alarming reading are supportable from the same tables. This piece sets out which is which.

What the upper limit of normal for ALT should be, and why it is not

What the renal and hepatic outcome programmes actually measured, and over what duration.

One measurement, twenty companies, forty compounds

The Journal has read several hundred certificates from twenty companies. The number is almost always there; the method behind it…

Dose-limiting: a definition worth being strict about

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

Accreditation, scope, and the question nobody asks VendorInvestigate

Two signatures — one who performed the work, one who approved its release — are the ordinary regulated convention and are almost…

What the trials adjudicated, and how

We give background rates alongside trial rates, because an event occurring during treatment is not thereby caused by it.

Reading the receptor: what distinguishes survodutide from liraglutide at the molecular level

Receptor pharmacology explains more of the clinical picture than the dose does — and almost none of it appears in the material…

A percentage is not a specification

This piece takes the measurement apart into the decisions it is made of, because each decision moves the answer.

Reading the survodutide titration schedule as a regulatory artefact

What the regulatory dossiers actually contain on dose selection is remarkably thin, and worth knowing before treating the ladder…

Dose-limiting: a definition worth being strict about

An effect is dose-limiting when it prevents adequate intake, prevents normal activity, or produces a risk of its own. Discomfort…