c.falk

TL2 · Dijon

Contributes reviews on supplier material. Based in Dijon.

Joined 3 June 2025 · last posted 2d

87 posts, newest first. Showing up to 150.

Journal club: SUSTAIN 6 and its retinopathy signal Replied, post #120 · Evidence › Journal club · 26 Jul 2026 · 9 likes Two things can be true about SUSTAIN 6 at once: the mechanism is plausible and the evidence for the size of the effect is thin. Most of the argument here is people…
What consumer-accessible tests can and cannot determine — a second dataset Replied, post #125 · Analytics › Home & field testing · 26 Jul 2026 · 6 likes Picking up post #122: that is the part I would want checked first. Ultraviolet absorbance at 280 nanometres estimates concentration for peptides containing aromatic…
Insurance and replacement policies, compared Replied, post #111 · Sourcing › Logistics · 23 Jul 2026 · 0 likes Narrowing post #110, because the general version has more than one answer. Adding the boring version of insurance and replacement policies, because the interesting…
What a certificate commits its issuer to Replied, post #63 · Analytics › COA interpretation · 19 Jul 2026 · 0 likes The distinction between release testing and characterisation is one industrial documents make and retail ones usually do not. It is the difference between "we tested…
Peak-to-trough ratio at steady state for a weekly agent — the long version Replied, post #54 · Pharmacology › Pharmacokinetics · 18 Jul 2026 · 19 likes One more thing on Peak-to-trough ratio that took me far too long to see: the two figures people quote are not measuring the same quantity. Once you notice that, the…
Revisiting: Protein density versus volume when you cannot eat much Replied, post #78 · Nutrition & Training › Protein & intake · 18 Jul 2026 · 22 likes Worth separating two things that post #74 runs together. Protein targets during weight loss: the standard recommendation is 1.6 to 2.2 grams per kilogram of body…
What a reversed-phase purity number actually is Replied, post #53 · Analytics › HPLC & UHPLC · 14 Jul 2026 · 8 likes Particle size and column dimensions determine what resolution is achievable at all. A 5 micrometre 250 millimetre column and a sub-2 micrometre 100 millimetre column…
Pooling trials with different estimands Replied, post #77 · Evidence › Meta-analyses · 7 Jul 2026 · 0 likes Answering the question post #73 raises rather than the one it answers. Study quality and weighting: some meta-analyses weight all studies equally; others weight by…
Revisiting: What pooling buys you and what it destroys Replied, post #80 · Evidence › Meta-analyses · 5 Jul 2026 · 7 likes Adding the measurement that post #77 says would settle it. Adding what did not work for me on pooling buys, since the failures never get written up and they are half…
Semaglutide and gastric emptying — the mechanism behind most of the side-effect profile Replied, post #89 · Compounds › Semaglutide · 3 Jul 2026 · 12 likes Since semaglutide and gastric emptying keeps coming up, it should probably be a maintained page rather than a recurring thread. I am happy to draft it if someone with…
A supplier who responds to a discrepancy with silence — what changed since Replied, post #69 · Sourcing › Red flags · 24 Jun 2026 · 29 likes Saving this. It is the version I will quote when the question comes round again.
[2026 update] Regional warehouse stock versus direct despatch Replied, post #112 · Sourcing › Logistics · 24 Jun 2026 · 29 likes Practical answer on Regional warehouse stock versus direct, since the theoretical one is upthread: do the simplest check first, write down the result, and only then…
Second pass at: Orforglipron as a non-peptide: what changes when the molecule is small Started this topic · Compounds › Oral incretins · 23 Jun 2026 · 33 likes Second pass at: Orforglipron as a non-peptide: what changes when the molecule is small Writing it up because I had to work it out twice and would rather nobody else…
Insomnia at a dose step: reported experiences — the long version Replied, post #35 · Wellbeing › Sleep · 17 Jun 2026 · 2 likes I will take the caveat as seriously as the claim, which is the point of putting it there.
Publication patterns in the BPC-157 literature, examined Replied, post #12 · Compounds › Repair & healing peptides · 12 Jun 2026 · 32 likes Picking up post #9: that is the part I would want checked first. TB-500 is usually the 7-residue actin-binding fragment of thymosin beta-4, not the full 43-residue…
A structured critique template this community uses — a second dataset Replied, post #8 · Evidence › Study critique · 11 Jun 2026 · 15 likes Criticism is more useful when it is narrower. "The trial answers a different question from the one being asked" is actionable; "the trial is flawed" is not.
Micronutrient adequacy at low total intake Replied, post #8 · Nutrition & Training › Protein & intake · 6 Jun 2026 · 12 likes The arithmetic in post #7 is right; the assumption feeding it is the part to check. What would change my mind on micronutrient adequacy is a second dataset collected by…
An 18-month record including the parts that went badly Replied, post #33 · Outcomes › Progress reports · 5 Jun 2026 · 0 likes I have been on both sides of the 18-month record argument in this category within eighteen months, which should tell you how strong the evidence for either side is.
Why we ask for units every single time, with three examples of what goes wrong Replied, post #19 · Start Here › How to Ask · 5 Jun 2026 · 33 likes Post #17 and I disagree about the size of the effect, not about the direction. Avoid "any advice?" at the end. It is so generic that people do not know which part of…
Journal club: indirect comparison between two programmes, defended and attacked Replied, post #55 · Evidence › Journal club · 13 May 2026 · 16 likes Adding a data point of agreement rather than a data point.
0.3 mL versus 0.5 mL versus 1 mL barrels: resolution matters Replied, post #36 · Devices › Syringes & needles · 9 May 2026 · 14 likes I had written a reply contradicting post #32 and deleted it. Here is what survived. 0.3 ml versus 0.5 ml came up in a thread eighteen months ago and was answered well.…
The best-written scientific paper you have read Replied, post #30 · Lounge › Off topic · 4 May 2026 · 1 like Practical answer on best-written scientific paper, since the theoretical one is upthread: do the simplest check first, write down the result, and only then decide…
Gastro-oesophageal reflux: improving or worsening? Replied, post #38 · Clinical › Comorbidities · 22 Apr 2026 · 0 likes Something worth flagging about gastro-oesophageal reflux: the strongest-sounding claims in this thread are the ones with no source attached, which is the usual pattern…
Revisiting: The report format the maintainers ask for, and why each field is there Replied, post #50 · Sourcing › Vendor reports · 13 Apr 2026 · 2 likes Do not adjust a reported figure. Post what the laboratory said and put your interpretation in a separate sentence.
Spike-and-recover accuracy for a peptide assay Replied, post #75 · Analytics › Method validation · 9 Apr 2026 · 27 likes The failure mode on spike-and-recover accuracy is boring rather than dramatic. It is almost always the step everyone assumes was done correctly because it is too simple…
Managing an unplanned gap in supply Replied, post #90 · Access › Shortages · 9 Apr 2026 · 0 likes Agreed on all of that, and I have nothing to add to it.
Reading a preclinical wound-healing model and its relevance to a human tendon — a second… Replied, post #34 · Compounds › Repair & healing peptides · 11 Mar 2026 · 5 likes Post #31 describes the usual case. This is about the unusual one. The preclinical work is genuinely interesting and it is preclinical. A rodent tendon model is a model…
The most common factual error about semaglutide on the internet — what changed since Replied, post #45 · Compounds › Semaglutide · 9 Mar 2026 · 11 likes STEP 1 and STEP 4 are two different questions. The first asks what happens when treatment is added; the second asks what happens when it is withdrawn after a run-in.…
Revisiting: Absolute versus relative contraindications Replied, post #40 · Safety › Contraindications · 9 Mar 2026 · 6 likes Everything in post #36 holds. The case it does not cover is the one I have. What I would check first on Absolute versus relative contraindications is whether the thing…
Air bubbles in a subcutaneous injection: the honest risk assessment — does this still… Replied, post #9 · Practice › Administration · 5 Mar 2026 · 3 likes If you have to inject at a different time of day than usual, that is a much smaller perturbation than it feels for a weekly compound with a week-long half-life. One…
The lowest dose that does anything: is that a real question? Replied, post #26 · Practice › Dosing & titration · 3 Mar 2026 · 0 likes Dose and effect are not linear across the studied range for every compound in this class. Assuming a doubled dose gives a doubled effect is the reasoning error behind…
[2026 update] Thyroid function tests during substantial weight change Replied, post #4 · Clinical › Bloodwork · 25 Feb 2026 · 0 likes This follows the opening post rather than contradicting it. Renal function markers: eGFR is estimated, not measured. It depends on creatinine, age, and weight. A small…
Coming back to: Training through a dose escalation week Replied, post #11 · Nutrition & Training › Resistance training · 19 Jan 2026 · 2 likes Clear enough that I do not think I have a follow-up, which is unusual.
Coming back to: Semaglutide in people without diabetes: what the evidence base looks like Replied, post #24 · Compounds › Semaglutide · 15 Jan 2026 · 5 likes Is there a ceiling dose beyond which the effect plateaus? The trials did not study that because they stopped at 2.4 mg. Some people report trying higher doses, but…
Measurement error in home scales, with a worked standard deviation — the long version Replied, post #6 · Research Methods › Statistics · 2 Jan 2026 · 12 likes Where the Measurement error in home scales discussion usually stalls is that nobody wants to say "I do not know" and everyone is willing to say "it varies". Those are…
Coming back to: Private prescribing in the UK: what is actually involved Replied, post #4 · Regional › UK & Ireland · 21 Dec 2025 · 2 likes Adding the measurement that the opening post says would settle it. Members outside these two jurisdictions reading this thread should note that none of it transfers,…
[2026 update] Whether protein timing matters at a large deficit Replied, post #5 · Nutrition & Training › Protein & intake · 15 Dec 2025 · 22 likes Second this, and I would have said it less carefully.
Follow-up: Bug report: the reconstitution calculator and a rounding edge case Replied, post #3 · Data & Tools › Calculators · 13 Dec 2025 · 1 like Precision and significant figures: the calculators do not round to match your input precision. If you input values to one decimal place, the output might have more. Use…
Adolescents: a distinct evidence base — one year on Replied, post #42 · Clinical › Special populations · 10 Dec 2025 · 14 likes Worth separating Adolescents as a question about the compound from Adolescents as a question about the documentation. They get answered by different people and only one…
Dose numbers for oral formulations are not comparable to injectable ones Replied, post #7 · Compounds › Oral incretins · 28 Nov 2025 · 4 likes PIONEER 6 was a cardiovascular safety trial for oral semaglutide, not an efficacy trial. Non-inferiority for safety was demonstrated. The point estimates favoured the…
Follow-up: Constipation management, with a dietitian's contribution Replied, post #21 · Practice › Side effects · 9 Nov 2025 · 2 likes Saving this. It is the version I will quote when the question comes round again.
Why an oral GLP-1 agonist is a formulation achievement more than a chemistry one Replied, post #25 · Compounds › Oral incretins · 31 Oct 2025 · 15 likes Tablet integrity matters more than people expect for a formulation that depends on an absorption enhancer released at a particular place. Splitting or crushing is not a…
Reading SURMOUNT-1 without the press release Replied, post #37 · Compounds › Tirzepatide · 18 Oct 2025 · 1 like Adding a null result on reading SURMOUNT-1 without the press. I looked, carefully, and found nothing, and null results deserve posting precisely because they never are.
Request: a diff view for wiki revisions — the long version Replied, post #45 · Meta › Feature requests · 20 Sep 2025 · 13 likes Filing a mild objection to the consensus on diff view for wiki revisions. Mild because I might be wrong; an objection because nobody has addressed the case that does…
Reverse causation in a cohort study of weight and outcome — a second dataset Replied, post #97 · Evidence › Study critique · 15 Sep 2025 · 0 likes Narrowing post #94, because the general version has more than one answer. Hold a trial to the standard something could actually have met. A criticism that no achievable…
AOD-9604 and the fragment hypothesis, revisited Replied, post #14 · Compounds › Other compounds · 12 Sep 2025 · 0 likes Picking up post #13: that is the part I would want checked first. Several compounds discussed here have no published human pharmacokinetics at all. That means half-life…
Hepatic impairment and the absence of data Replied, post #28 · Clinical › Special populations · 6 Sep 2025 · 0 likes Post #27 is right about the mechanism and I think understates the practical bit. I read the earlier replies on hepatic impairment twice before writing this, because I…
Confounding by indication, explained with a concrete example Replied, post #22 · Evidence › Study critique · 3 Sep 2025 · 2 likes Hold a trial to the standard something could actually have met. A criticism that no achievable design could have answered is a criticism of the field rather than of the…
When a preprint is the best available evidence and we say so Replied, post #130 · Evidence › Preprints · 2 Sep 2025 · 12 likes Sensible. I would want the same detail before I acted on it either.
Second pass at: Why this subcategory is stricter about sourcing than most Replied, post #119 · Compounds › Secretagogues & GH axis · 31 Aug 2025 · 0 likes On analysis: these are short peptides and generally straightforward chromatographically, which means a poor purity result is more likely to reflect the synthesis than…
A ten-fold dose error caught before injection — one year on Replied, post #107 · Devices › Syringes & needles · 4 Aug 2025 · 25 likes Right — I had this wrong and I am glad to have read it before it mattered.
Substitution between formats during a shortage Replied, post #33 · Access › Shortages · 4 Aug 2025 · 6 likes Where I part company with post #29, and it is a narrow parting. Allocation and rationing: during severe shortages, suppliers might ration allocation to prescribers.…
Antibiotics and a course of something with delayed emptying Replied, post #102 · Practice › Interactions · 27 Jul 2025 · 0 likes Agreed, and I will stop repeating the version of this I had been repeating.
Pooling trials with different estimands — what changed since Replied, post #6 · Evidence › Meta-analyses · 23 Jul 2025 · 1 like Post #3 is the version of this I will quote in future. One addition. When trials differ in population, duration and comparator, the pooled estimate answers a question…
Specification in the result column: why that is a meaningful error Replied, post #17 · Analytics › COA interpretation · 10 Jul 2025 · 2 likes Helpful, and short, which on this subject is harder than long.
Interim analyses and stopping rules — does this still hold? Replied, post #35 · Evidence › Trials · 5 Jul 2025 · 13 likes Absolute numbers, not just relative: a 30% relative reduction tells you the ratio but not the practical magnitude. The event rate in each arm and the difference between…
[2026 update] What we do not know about retatrutide, listed explicitly Replied, post #2 · Compounds › Retatrutide · 3 Jul 2025 · 1 like A theoretical mass for retatrutide is not published in the peer-reviewed literature in a form worth quoting. A report should state the mass observed on the instrument…
Coming back to: Sample size calculations, read backwards from the published number Replied, post #43 · Evidence › Trials · 20 Jun 2025 · 7 likes The strongest argument against my own position on Sample size calculations, stated as well as I can state it, since nobody else has yet.
Coming back to: Getting a referral rather than a refusal Replied, post #13 · Clinical › Prescriber conversations · 29 May 2025 · 28 likes Prescription logistics: confirm whether it will be filled locally, requires mail order, or will be prescribed off-label and needs a compounding pharmacy. Different…
DXA precision and the least significant change for lean mass — the long version Replied, post #105 · Outcomes › Body composition · 27 May 2025 · 10 likes I read post #103 twice before replying, because I had assumed the opposite. Ultrasound: thickness of subcutaneous fat at specific sites. Less standardised than DXA and…
Pre-registering a personal experiment, seriously Replied, post #9 · Research Methods › N-of-1 designs · 26 May 2025 · 0 likes I have no financial interest in anything named in this thread and I want to say so before I comment on pre-registering a personal experiment, because it is the sort of…
Airline travel with a temperature-sensitive injectable — what changed since Replied, post #30 · Devices › Cold chain · 22 May 2025 · 1 like I came in to disagree and I am leaving without a disagreement.
Splitting a vial for two laboratories: how to do it without ruining both Replied, post #31 · Sourcing › Independent verification · 2 May 2025 · 0 likes Method has to travel with the number. A verification record without the method is not a record; it is a figure.
[2026 update] Citation sweep results: how many references did not say what was claimed Replied, post #24 · Meta › Wiki maintenance · 22 Apr 2025 · 11 likes Following this. I have the same question and no better information than the first post.
Journal club: SUSTAIN 6 and its retinopathy signal — does this still hold? Replied, post #66 · Evidence › Journal club · 1 Apr 2025 · 0 likes Fine by me. I had wanted a stronger conclusion and there is not one available.
Obstructive sleep apnoea and a hard endpoint in this class Replied, post #42 · Clinical › Comorbidities · 26 Mar 2025 · 5 likes Worth stating the null on obstructive sleep apnoea before we explain it: the observation may be nothing. That possibility deserves a sentence and usually does not get…
Second pass at: Journal club: STEP 4 and what a withdrawal design can prove Replied, post #4 · Evidence › Journal club · 23 Mar 2025 · 1 like The baseline characteristics table is the single most useful page for the questions that get asked here, because it tells you who the result applies to. The evidence…
Biased agonism: a real phenomenon, an over-used explanation Replied, post #93 · Pharmacology › Receptor biology · 14 Mar 2025 · 3 likes Ghrelin receptor agonism drives growth hormone release in pulses and also increases appetite, which is the effect people most reliably report and least often want.
Individual participant data versus aggregate data Replied, post #22 · Evidence › Meta-analyses · 12 Mar 2025 · 1 like I changed my mind about individual participant data versus aggregate after someone here asked me for the source and I could not produce one. That is worth saying out…
A promotion I argued against, and why I lost Replied, post #125 · Documentation › Doc review · 8 Mar 2025 · 0 likes The most useful review comment names a sentence and says what is wrong with it. General approval and general concern are both hard to act on. I would want a second…
Introducing myself and asking whether my planned first topic belongs anywhere Replied, post #14 · Start Here › Welcome · 8 Mar 2025 · 13 likes That matches what I have seen, for whatever a single anecdote is worth.
Adducts: sodium, potassium, and the peak you did not expect Replied, post #28 · Analytics › Mass spectrometry · 7 Mar 2025 · 24 likes Resolution: "high resolution" commonly means
Adjudicated events and why the definition matters — the long version Replied, post #19 · Evidence › Trials · 21 Feb 2025 · 14 likes This follows post #18 rather than contradicting it. Subgroup analyses are hypothesis-generating unless pre-specified and adequately powered, and almost none are the…
Journal club: SURMOUNT-1, read without the press release Replied, post #57 · Evidence › Journal club · 8 Feb 2025 · 6 likes The version of SURMOUNT-1 that circulates here is a simplification of a simplification. It is not wrong, but it has lost the conditions under which it holds, and those…
Introducing myself and asking whether my planned first topic belongs anywhere Started this topic · Start Here › Welcome · 27 Jan 2025 · 3 likes Introducing myself and asking whether my planned first topic belongs anywhere Writing it up because I had to work it out twice and would rather nobody else did.…
Pancreatitis history and the risk calculus — a second dataset Replied, post #21 · Safety › Contraindications · 25 Jan 2025 · 1 like Post #17 describes the usual case. This is about the unusual one. I would be cautious about generalising from the Pancreatitis history example above. It is a good…
Follow-up: Tirzepatide's shorter half-life and its one practical consequence Replied, post #128 · Compounds › Tirzepatide · 4 Jan 2025 · 0 likes Post #124 put the caveat in the right place and I want to underline it. The apnoea-hypopnoea index used in SURMOUNT-OSA is an objective measurement rather than a…
Fixed versus detachable needles: the trade-offs Replied, post #72 · Devices › Syringes & needles · 26 Dec 2024 · 2 likes Reading rather than answering, but this is the post I would point somebody at.
When "no data" is the complete and final answer Replied, post #43 · Compounds › Other compounds · 16 Dec 2024 · 2 likes Post #42 answers the question as asked. The question underneath it is different. Thymosin alpha-1 has a regulatory history in several jurisdictions and a real clinical…
Time to steady state after a dose increase Replied, post #118 · Pharmacology › Pharmacokinetics · 5 Nov 2024 · 30 likes Post #116 and I disagree about the size of the effect, not about the direction. Between-person variability in exposure is substantial and is the reason two people on…
Follow-up: Recovery when intake is low: what to cut first Replied, post #6 · Nutrition & Training › Resistance training · 4 Nov 2024 · 14 likes Two things can be true about Recovery at once: the mechanism is plausible and the evidence for the size of the effect is thin. Most of the argument here is people…
Coming back to: The nausea timeline across the first four weeks, with a tabulated log Replied, post #24 · Practice › Side effects · 1 Nov 2024 · 19 likes The published rates come from populations that were titrated on a defined schedule with clinical supervision. Rates from a forum are not comparable and are biased by…
Second pass at: Food noise reducing and the disorientation that can follow Replied, post #53 · Wellbeing › Mental health · 27 Oct 2024 · 0 likes For anyone finding this later: the short answer on Food noise is that it depends on one thing, and the rest of the thread is people identifying which thing.
Second pass at: Hoarding and why it makes a shortage worse Replied, post #68 · Access › Shortages · 11 Oct 2024 · 25 likes Shortage-driven price movement is real and is a separate question from availability. Posted with less confidence than the sentence structure implies.
Coming back to: Purity assay versus content assay: two different numbers Replied, post #33 · Analytics › COA interpretation · 10 Aug 2024 · 20 likes Bookmarking this. I will come back when I have something worth adding.
Journal club: FLOW and the renal composite, component by component Replied, post #8 · Evidence › Journal club · 8 Jul 2024 · 14 likes Reading order that works for these sessions: registry entry, methods, baseline table, primary result, then abstract last. Reading the abstract first anchors everything…
Assessing a warm arrival: the decision process — one year on Replied, post #2 · Sourcing › Logistics · 27 May 2024 · 10 likes The opening post answers the question as asked. The question underneath it is different. Delivery to an address where somebody is present is worth more for cold-chain…