April 2025

The GLP-1 receptor is not a switch, and survodutide is not a key

What the in-vitro data supports, what it does not, and where the extrapolation to a person begins.

The upper rungs, ranked by evidence

Where the curve flattens, what flattens with it, and what does not.

The interventions with trial support, and the much longer list without

We separate what is supported, what is reasonable, and what is folklore, and we do not pretend the boundaries are crisp.

The mechanism behind the mechanism

The receptor populations that produce satiety and the ones that produce nausea overlap substantially. That is why the ceiling of…

Three weeks off is a fresh start, whether or not you want one

Concentrations fall by half a week, so a month away leaves a small fraction of steady state. Resuming at the previous dose…

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 a month without the drug does to tolerability

Concentrations fall by half a week, so a month away leaves a small fraction of steady state. Resuming at the previous dose…

The mechanism behind the mechanism

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

A document, not a test: what a certificate actually is

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

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 question no chromatogram has ever answered

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

Endotoxin is not a microorganism, and killing the bacteria does not remove it

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

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.

Four ways a peptide comes apart

The sequence predicts the failure mode. A methionine predicts oxidation; an asparagine followed by a glycine predicts…

The header, the table and the signature block

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

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

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

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.

Two sessions a week, and the evidence behind the prescription

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

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…

What the pharmacokinetics permit and what they cannot tell you

A great deal of practice has grown up around intermittent schedules. The randomised evidence for any of them is, as far as the…

What TRIUMPH-1 tells us about maintenance, and what it does not

Dose reduction is not withdrawal, and the trials that tested withdrawal cannot be read as testing it.

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.

A vial can be 99.4 per cent pure and not sterile in the same afternoon

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

Mass spectrometry answers a different question, properly

The most useful single addition to any purity determination is a second separation under a different pH or on a different…

Where the solvent front ends is a decision, not a fact

Regulated pharmaceutical practice has explicit reporting, identification and qualification thresholds. This trade has none,…

Twenty-eight days is a number from somebody else’s product

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

Leucine, isoleucine, and a difference no balance can measure

Stereochemical inversion changes the molecule, changes its biology, and changes its mass by exactly nothing.

The conservative convention: report the lower of two numbers

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

LAL, kinetic chromogenic, recombinant factor C: three ways to the same figure

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

Pancreatitis, obstruction, gallbladder: three things nausea can be

A small number of serious gastrointestinal events occur in people taking these drugs. Distinguishing them from the expected…

A needle is a single-use instrument

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

Continued treatment against continued placebo: the comparison that settled it

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

The out-of-range flag is a statistical convention with a printer attached

A twelve-analyte panel in a perfectly healthy person has roughly even odds of producing at least one flagged result.

Gallstones during rapid weight loss: drug, or weight loss?

The features that should prompt urgent assessment, stated once and plainly.

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

Micronutrient guidance for this drug class is borrowed almost entirely from post-bariatric surveillance, where the anatomy is…

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 shortage years, and what they taught about interruption

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

A tested vial is evidence about a vial

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

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.

The lowest effective dose is a real concept with almost no data behind it

A survey of the maintenance evidence, which is shorter than the survey of the withdrawal evidence.

A tested vial is evidence about a vial

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

What STEP 8 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…

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

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

SURMOUNT-OSA was built to answer the stopping question, and it did

The evidence on stopping is better than the evidence on almost anything else in this field, because somebody deliberately…

The one-quarter rule, and the paper that took it apart

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

What PeptideMeter can tell you about a vial by weighing its water

The physics of the drying cycle explains why some cakes are matte and full-volume and others are glassy discs, and why the…

Calibrated, qualified, accredited: three words that are not synonyms

An assay against a quantitative reference standard measures how much is present. Area per cent measures what proportion of the…

How much water: the question with no single right answer

The diluent choice affects preservation and in-use period rather than the arithmetic — but the wrong choice for a multi-dose…

Choosing 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…

The cake tells you something, and it is not purity

Dye ingress and microbial immersion are probabilistic. Vacuum decay, high-voltage leak detection and helium mass spectrometry…

The cake is a record of the cycle that made it

Lyophilisation does not stop degradation. It slows every pathway by removing the solvent that most of them require, and the…

Five lines that would change what a certificate is worth

The Journal wrote to twenty companies asking five specific questions about sterility assurance. We report the response rate, the…

The incretin receptors, ranked by how much we actually know about them

Selectivity, potency and efficacy are three different measurements. The trade routinely reports none of them.

Why purity is the cheapest number to flatter

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

Site selection when the tissue has already changed

The evidence base here is the insulin injection-technique literature, which is large and transfers well on tissue questions.

The specification sheet says 500,000. The report says conforms.

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

Vagal afferents, the area postrema, and the anatomy of nausea

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

Mapping a rotation that you will actually follow

Repeated injection into the same small area produces lipohypertrophy — thickened, rubbery subcutaneous tissue with blunted and…

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…

Three receptors, one peptide: the design problem behind triple agonism

Head-to-head data exists for some of these comparisons and not for others. This piece says which.