March 2025

Delayed emptying explains some of this, and not all of it

A single drug producing both constipation and diarrhoea looks contradictory until the motility data is read properly.

When a symptom is information and when it is noise

The practice is near-universal, clinically sensible, and supported by observational data rather than randomised comparison. We…

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…

Antiemetics, laxatives and the thin literature underneath them

Constipation is the most tractable of the effects and the most consistently under-managed.

The eighteenth month, and the conversation that should have happened in the third

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

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

What the trials counted as intolerance

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

Accreditation, scope, and the question nobody asks PeptideMeter

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

The named comparison we promised two years ago

Two years ago we ran an anonymised version of this comparison and promised a named one. This is it, with every method printed in…

Six words a verification badge would need to mean anything

Every step between the laboratory report and the product page removes information, and the badge is the last step.

The submitted sample: the weakest link in the whole system

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

What VendorInvestigate is able to certify about a sealed vial, and what it is not

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

Aggregation: the impurity your chromatogram dissolved before it looked

Deamidation, oxidation, aggregation and hydrolysis account for nearly all of what happens to a peptide over time. Each has a…

What PeptideMeter charges to answer the pyrogen question

The masking phenomenon known as low endotoxin recovery means a formulation can return a clean result while containing endotoxin…

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

The variance around the mean regain trajectory is large and unexplained, exactly as it is for the weight loss.

Falling ferritin is not always falling iron

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

Why the bone question is harder than the muscle question

Density is a proxy for strength and an imperfect one, particularly when soft-tissue thickness over the measurement site is…

Not everybody regains at the same rate, and nobody knows why

What returns, in what order, and how much of the benefit survives.

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

A plausible mechanism, a measurable change, and no outcome data. This is what an open question looks like.

Why the recent month counts for half the number

The assay is not the problem. The interpretation of a lagging integral as a current measurement is the problem.

The shortage years, and what they taught about interruption

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

Tapering: a word borrowed from drugs with withdrawal syndromes

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

A named analyst is the cheapest quality signal in this trade

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

What twenty companies say about storage, and what they have measured

A retest date says that material should be re-examined before use. An expiry date says it should not be used. The trade uses the…

The sample is not the batch

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

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

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

A method is a set of numbers. All of them belong on the certificate.

Column chemistry, particle size and pore diameter determine what the separation is capable of before the gradient is even…

When a better instrument changes the answer rather than the confidence

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

Three services, one lot, and a spread of two and a half points

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

Three compendial method families are in routine use and a fourth, based on a recombinant enzyme rather than crab lysate, is now…

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

Mass and function are different endpoints and training affects them differently. Most coverage treats them as one.

Two sessions a week, and the evidence behind the prescription

The older-adult diet-and-exercise trials are the closest analogue to rapid pharmacological weight loss, and they are twenty…

Why your laboratory interval differs from the one in the textbook

The arithmetic of the reference change value, worked for the analytes that matter here.

Tolerability is the ceiling, and the ceiling is personal

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

Micronutrient monitoring: which panel, how often, and on whose evidence

A monitoring schedule requires evidence about incidence. For this population, that evidence does not exist.

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

The estimated glomerular filtration rate is calculated from creatinine, creatinine comes from muscle, and muscle mass is…

Gauge, pain and flow rate

The insulin injection-technique literature is large, well conducted and directly transferable on questions of depth and tissue.…

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

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

A design note on withdrawal trials, and why the run-in matters

The regain trajectories, arm by arm, with the estimands named.

Maintenance dosing: what is licensed, what is practised, and what is evidenced

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

How a claim degrades between the bench and the listing

The Journal does not treat a badge as evidence and states so wherever it reports one.

The supply gap as a clinical event

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

Chain of custody, and where it begins

What a laboratory can and cannot know about the provenance, storage history and representativeness of what lands on its bench.

A tested vial is evidence about a vial

Every third-party report in this market describes a sample somebody chose to send. That choice is outside the laboratory’s…

What a split-sample exercise can establish, and what it cannot

Two years ago we ran an anonymised version of this comparison and promised a named one. This is it, with every method printed in…

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

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

How a correct calculation becomes a wrong dose

We have catalogued what readers report, ranked by the size of the dosing error each produces.

Storage after reconstitution, and the evidence behind the numbers

Sharps disposal is a legal obligation in most jurisdictions and a safety obligation everywhere. Household waste is not a route.

Five lines that would change what a certificate is worth

None of what this piece asks for is commercially sensitive, and all of it is already known to whoever released the batch.

A few hundred participants carry the whole body-composition argument

What was pre-specified, what was exploratory, and what was calculated afterwards by people who did not run the trial.

Turnaround, cost and accreditation across the services this trade relies on

Endotoxin is the more tractable of the two questions, and a kinetic chromogenic determination is neither slow nor exotic. It is…

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

Reduced intake is a plausible mechanism for deficiency. Reduced absorption is not, and the two are conflated in most of the…

The 0.22 micron filter does the work, and it is the last line

Bioburden entering the filter, filter integrity, environmental monitoring and aseptic process simulation are the four pillars.…

When a symptom is information and when it is noise

A dose held long enough stops being a pause and becomes a maintenance decision. That transition is rarely made explicitly.

Do you need the top of the ladder?

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

The incidence tables, read line by line

Trial adverse-event tables count episodes reported to a study nurse. They are the best data we have and they systematically…

Six things incretin pharmacology cannot currently predict

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

How a correct calculation becomes a wrong dose

A pharmacist catches most of these in licensed practice. In this market there is no pharmacist, so the checks have to be…

Delayed emptying explains some of this, and not all of it

What scintigraphy and breath-test studies established about emptying rate, and what they did not.

The restart nobody plans for

We work through the residual-exposure table so the decision can be made from numbers rather than from feel.