e.roos

TL2 · Haarlem

Contributes reviews on supplier material. Based in Haarlem.

Joined 28 December 2024 · last posted 3d

85 posts, newest first. Showing up to 150.

Seven-day rolling means and why weekly readings mislead Replied, post #108 · Outcomes › Progress reports · 25 Jul 2026 · 29 likes Post #106 describes the usual case. This is about the unusual one. A seven-day rolling mean of daily readings has a much smaller standard error and makes most apparent…
Coming back to: A structured critique template this community uses Replied, post #67 · Evidence › Study critique · 24 Jul 2026 · 1 like Sensible. I would want the same detail before I acted on it either.
What to bring: records that a clinician can actually use — a second dataset Replied, post #69 · Clinical › Prescriber conversations · 23 Jul 2026 · 0 likes Post #65 describes the usual case. This is about the unusual one. Prescription logistics: confirm whether it will be filled locally, requires mail order, or will be…
What a reversed-phase purity number actually is Replied, post #82 · Analytics › HPLC & UHPLC · 22 Jul 2026 · 0 likes Peak purity: a diode-array detector records a spectrum at every time point. If a peak contains two co-eluting species with different spectra, the spectrum changes…
What a certificate commits its issuer to Replied, post #74 · Analytics › COA interpretation · 21 Jul 2026 · 8 likes Worth separating two things that post #73 runs together. The distinction between release testing and characterisation is one industrial documents make and retail ones…
What a reversed-phase purity number actually is Replied, post #63 · Analytics › HPLC & UHPLC · 17 Jul 2026 · 24 likes I read post #59 twice before replying, because I had assumed the opposite. A definition problem is doing most of the work in this reversed-phase purity number…
Coming back to: Lateral-flow and colorimetric approaches: the specificity problem Replied, post #77 · Analytics › Home & field testing · 15 Jul 2026 · 0 likes On post #74 — agreed on the reasoning, with one qualification. I have been on both sides of the Lateral-flow and colorimetric approaches argument in this category…
[2026 update] Travelling with an injectable: documentation and practicalities Replied, post #81 · Access › International · 15 Jul 2026 · 0 likes A regional experience posted here should say which year it describes. The archive keeps these permanently and they age faster than anything else on the site.
Aggregate verification data across the directory, with caveats Replied, post #46 · Sourcing › Independent verification · 14 Jul 2026 · 11 likes Agreed, and I will stop repeating the version of this I had been repeating.
A supplier who responds to a discrepancy with silence — what changed since Replied, post #79 · Sourcing › Red flags · 11 Jul 2026 · 16 likes Post #78 answers the question as asked. The question underneath it is different. Posting my supplier numbers with the method attached so they can be discounted…
[2026 update] Regional warehouse stock versus direct despatch Replied, post #108 · Sourcing › Logistics · 20 Jun 2026 · 0 likes A definition problem is doing most of the work in this Regional warehouse stock versus direct discussion. Once the term is pinned down I suspect the disagreement mostly…
Second pass at: Programming during a large energy deficit Replied, post #15 · Nutrition & Training › Resistance training · 5 Jun 2026 · 0 likes That is consistent with mine, for whatever one more account is worth.
Batch numbers that do not match the vial label Replied, post #22 · Sourcing › Red flags · 29 May 2026 · 8 likes Evasion when asked: if a supplier does not clarify when asked specifically for method details, counter-ion form, or batch origin, that itself is a red flag worth…
Getting a referral rather than a refusal Replied, post #12 · Clinical › Prescriber conversations · 18 May 2026 · 0 likes Answering the question post #10 raises rather than the one it answers. A second opinion is a normal part of medicine rather than an accusation, and asking how to obtain…
Spreadsheets: an appreciation — what changed since Replied, post #25 · Lounge › Off topic · 23 Apr 2026 · 21 likes Genuine question rather than a rhetorical one: has anyone here actually observed Spreadsheets, as opposed to read about it? The thread is long and I cannot tell.
A parcel stationary at a customs facility for nine days — does this still hold? Replied, post #12 · Sourcing › Logistics · 30 Mar 2026 · 21 likes Useful. I have added it to my own notes with the date on it.
Run-in periods and the population they select Replied, post #84 · Evidence › Trials · 19 Mar 2026 · 12 likes Answering the question post #81 raises rather than the one it answers. What I would check first on run-in periods is whether the thing being measured moved or whether…
Contributing data without breaching anyone's privacy Replied, post #70 · Data & Tools › Datasets · 6 Mar 2026 · 0 likes Small correction to my own earlier position on contributing data without breaching. I had the units the wrong way round, which changes the conclusion by an order of…
[2026 update] What a purity-only report leaves out Replied, post #42 · Sourcing › Independent verification · 3 Mar 2026 · 28 likes Practical note on purity-only: write down what you expect before you look. The number of times I have found what I went looking for is higher than chance would allow.
Why "dose equivalence" between different incretin analogues is a weak concept Replied, post #86 · Practice › Dosing & titration · 19 Feb 2026 · 2 likes The arithmetic in post #84 is right; the assumption feeding it is the part to check. Titrating on symptoms rather than on the calendar is what most people here actually…
[2026 update] Regional warehouse stock versus direct despatch Replied, post #3 · Sourcing › Logistics · 19 Feb 2026 · 10 likes This settles it for me, at least until somebody posts a reason it should not.
Where impurities in solid-phase peptide synthesis come from Replied, post #42 · Analytics › Impurities & related substances · 13 Feb 2026 · 0 likes Post #39 is right about the mechanism and I think understates the practical bit. Deletion sequences (incomplete coupling during synthesis): lower in mass by one…
Second pass at: What pooling buys you and what it destroys Replied, post #10 · Evidence › Meta-analyses · 17 Jan 2026 · 13 likes Grateful for the specificity. Vague answers to this question are what sent me looking.
Coming back to: Private prescribing in the UK: what is actually involved Replied, post #44 · Regional › UK & Ireland · 7 Jan 2026 · 0 likes Where the compound is supplied with a device, the device and the compound have separate availability positions and the device is more often the constraint. If this…
Gastro-oesophageal reflux: improving or worsening? Replied, post #9 · Clinical › Comorbidities · 5 Jan 2026 · 1 like Where somebody is on several medicines, the interaction question and the comorbidity question are entangled and both belong with a pharmacist.
A widely repeated interaction claim that turns out to be unsupported Replied, post #16 · Practice › Interactions · 2 Jan 2026 · 5 likes Post #15 is right about the mechanism and I think understates the practical bit. Absence of an interaction study is not evidence of no interaction. A great many…
Common supplements people ask about, assessed one at a time — a second dataset Replied, post #28 · Practice › Interactions · 31 Dec 2025 · 0 likes Research-use-only compounds have no interaction data of any kind, because interaction studies are done on medicines being developed for use in people.
Interpreting a result that disagrees with the supplier's certificate Replied, post #45 · Sourcing › Independent verification · 16 Dec 2025 · 3 likes Interpreting a result came up in a thread eighteen months ago and was answered well. I cannot find it, which is itself the problem, so here is the reconstruction.
Adsorptive losses at low concentration, and why dilute solutions are fragile Replied, post #5 · Practice › Storage & stability · 15 Dec 2025 · 12 likes The version of adsorptive losses that circulates here is a simplification of a simplification. It is not wrong, but it has lost the conditions under which it holds, and…
Tirzepatide's shorter half-life and its one practical consequence Replied, post #29 · Compounds › Tirzepatide · 11 Dec 2025 · 9 likes Categorical response thresholds — the proportion reaching ten, fifteen or twenty per cent reduction — are more persuasive and less informative than the mean. They…
Documentation that materially improves an appeal's chances Replied, post #94 · Access › Insurance & coverage · 7 Dec 2025 · 4 likes Small correction to my own earlier position on documentation. I had the units the wrong way round, which changes the conclusion by an order of magnitude and therefore…
[2026 update] How much of the diluent volume the powder itself displaces Replied, post #21 · Practice › Reconstitution · 23 Nov 2025 · 6 likes Do not shake. Swirl, or leave it. Vigorous agitation introduces air and shear, and neither helps a peptide go into solution any faster than patience does. That holds…
Follow-up: Constipation management, with a dietitian's contribution Replied, post #31 · Practice › Side effects · 21 Nov 2025 · 6 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…
Stepping down deliberately, and how to do it without losing progress Replied, post #16 · Practice › Dosing & titration · 18 Nov 2025 · 0 likes Concentration and dose get conflated constantly in this subcategory. Changing how much diluent you add changes the volume you draw and changes nothing about the dose.
Pen dose counters: what a click does and does not guarantee Replied, post #2 · Devices › Pens & autoinjectors · 11 Nov 2025 · 33 likes Nothing to add, except that this is the answer I would give if asked.
Appeal templates and why they are deliberately unemotional Replied, post #21 · Access › Insurance & coverage · 3 Nov 2025 · 1 like Filing a mild objection to the consensus on appeal templates. Mild because I might be wrong; an objection because nobody has addressed the case that does not fit.
The 2.5 mg starting dose is not a therapeutic dose — why that matters — a second dataset Replied, post #3 · Compounds › Tirzepatide · 27 Oct 2025 · 1 like The opening post answers the question as asked. The question underneath it is different. SURPASS-2 compared tirzepatide with semaglutide 1.0 mg, the licensed diabetes…
Sleep tracking data and its considerable limitations Replied, post #67 · Wellbeing › Sleep · 23 Oct 2025 · 18 likes The published data on sleep outcomes in this class is thinner than the volume of discussion, which is worth saying plainly.
Research-use-only labelling: what it means and what it does not Replied, post #42 · Sourcing › Regulatory · 6 Oct 2025 · 9 likes A label change is a regulatory event with a date and a document. Citing the document is what makes a claim about labelling checkable.
Retatrutide's phase 2 heart-rate signal and how to think about it Replied, post #5 · Compounds › Retatrutide · 29 Sep 2025 · 4 likes Confirming post #2 from a second method, which matters more than confirming it from a second person. Heart rate increased in a dose-dependent way in the phase 2 work.…
Column chemistry choices for a 40-residue peptide Replied, post #42 · Analytics › HPLC & UHPLC · 21 Sep 2025 · 31 likes Taking post #41 at face value and following it one step further. Counterpoint on column chemistry choices, offered without confidence: the same observation is…
Reverse causation in a cohort study of weight and outcome — a second dataset Replied, post #50 · Evidence › Study critique · 14 Sep 2025 · 4 likes Post #47 is the version of this I will quote in future. One addition. Adding a null result on Reverse causation. I looked, carefully, and found nothing, and null…
Hepatic impairment and the absence of data Replied, post #32 · Clinical › Special populations · 11 Sep 2025 · 7 likes Everything in post #28 holds. The case it does not cover is the one I have. I have been on both sides of the hepatic impairment argument in this category within…
The most useful thing you learned here that was not the answer you came for — a second… Replied, post #31 · Lounge › Off topic · 11 Sep 2025 · 19 likes Newer drugs and mechanisms: when a new drug launches or a new mechanism is discovered, the Lounge is a place to discuss the news and speculate before hard data exists.…
Second pass at: Coverage in the US: a map of the usual obstacles Replied, post #3 · Regional › North America · 10 Sep 2025 · 25 likes Provincial formularies in Canada are published and are the correct source for coverage information. Coverage for weight management is less common than for diabetes.
When a preprint is the best available evidence and we say so Replied, post #135 · Evidence › Preprints · 3 Sep 2025 · 28 likes Nothing to add on the substance. Thank you for taking the question at face value.
Second pass at: Why this subcategory is stricter about sourcing than most Replied, post #109 · Compounds › Secretagogues & GH axis · 28 Aug 2025 · 0 likes Adding a data point of agreement rather than a data point.
Revisiting: Reading a denial letter as a specification for your appeal Replied, post #87 · Access › Insurance & coverage · 20 Aug 2025 · 0 likes Confirming post #84 from a second method, which matters more than confirming it from a second person. Appeal deadlines are strict and are stated in the letter. Missing…
Angle of injection and whether 90 degrees is always right Replied, post #10 · Practice › Administration · 13 Aug 2025 · 4 likes On angle of injection I would separate what is worth knowing from what is worth acting on. The first list is long and the second is short, and conflating them is how…
How the vendor documentation pages are maintained, and by whom — what changed since Replied, post #37 · Sourcing › Vendor reports · 9 Aug 2025 · 0 likes Post #33 and I disagree about the size of the effect, not about the direction. The service matters to the interpretation. A documentation review and a chromatographic…
A ten-fold dose error caught before injection — one year on Replied, post #113 · Devices › Syringes & needles · 4 Aug 2025 · 0 likes Building on post #110 rather than restating it. Needle gauge: smaller numbers (30G) are finer and less painful. Larger numbers (25G) are courser. For subcutaneous…
The C-cell question: rodent findings and their human context Replied, post #46 · Compounds › Semaglutide · 2 Aug 2025 · 9 likes Renal outcomes moved this compound out of the metabolic-only conversation. FLOW reported on kidney endpoints in people with type 2 diabetes and chronic kidney disease,…
Thyroid function tests during substantial weight change Replied, post #19 · Clinical › Bloodwork · 1 Aug 2025 · 8 likes Worth separating two things that post #17 runs together. Ask what decision the result would change before ordering it. A test whose result changes nothing is a test…
Subcutaneous absorption kinetics and site differences Replied, post #18 · Pharmacology › Pharmacokinetics · 27 Jul 2025 · 31 likes This follows post #17 rather than contradicting it. Reading this subcutaneous absorption kinetics and site thread as someone who came in with a fixed view: the third…
Comparators chosen for regulatory reasons rather than clinical ones — one year on Replied, post #59 · Evidence › Trials · 22 Jun 2025 · 1 like Sensible. I would want the same detail before I acted on it either.
What a documentation review can and cannot tell you Replied, post #5 · Sourcing › Independent verification · 13 Jun 2025 · 16 likes The arithmetic in post #3 is right; the assumption feeding it is the part to check. Practical answer on documentation review, since the theoretical one is upthread: do…
Journal club: STEP 4 and what a withdrawal design can prove Replied, post #48 · Evidence › Journal club · 30 May 2025 · 17 likes Critical appraisal template: (1) What did the trial set out to estimate? (2) Could the design answer that question? (3) Was the population sufficiently similar to your…
DXA precision and the least significant change for lean mass — the long version Replied, post #112 · Outcomes › Body composition · 28 May 2025 · 0 likes Worth separating two things that post #108 runs together. Air displacement plethysmography and hydrostatic weighing have their own precision limits and their own…
Splitting a vial for two laboratories: how to do it without ruining both Replied, post #41 · Sourcing › Independent verification · 17 May 2025 · 0 likes Where I part company with post #37, and it is a narrow parting. Repeat determination on the same product line months apart is the measurement that speaks to…
A 10 mg vial reconstituted three different ways, compared — the long version Replied, post #52 · Practice › Reconstitution · 13 May 2025 · 8 likes Coming back to post #50, because the follow-up matters more than the original answer. Add the diluent down the side of the vial rather than directly onto the cake. It…
A ten-fold dose error caught before injection Replied, post #26 · Devices › Syringes & needles · 27 Apr 2025 · 10 likes Post #23 answers the question as asked. The question underneath it is different. Syringe barrel size: common sizes are 0.3 mL, 0.5 mL, and 1.0 mL. Smaller barrels are…
Cost per milligram, computed honestly across formats — the long version Replied, post #59 · Access › Pricing · 9 Apr 2025 · 11 likes Picking up post #58: that is the part I would want checked first. The most useful pricing posts here are the ones that show the arithmetic rather than the conclusion.
Carryover and the ghost peak from last week's standard Replied, post #38 · Analytics › HPLC & UHPLC · 6 Apr 2025 · 0 likes Marking my place. If it changes for me I will come back and say so.
Journal club: SURMOUNT-1, read without the press release Replied, post #90 · Evidence › Journal club · 4 Apr 2025 · 2 likes Post #88 answers the question as asked. The question underneath it is different. Marking my uncertainty on SURMOUNT-1 explicitly. I am confident about the direction,…
Adjudicated events and why the definition matters — the long version Replied, post #69 · Evidence › Trials · 28 Mar 2025 · 21 likes Adjudicated events: I would want to see the raw numbers rather than the summary before agreeing. Summaries lose exactly the information that would settle this.
Biased agonism: a real phenomenon, an over-used explanation Replied, post #87 · Pharmacology › Receptor biology · 13 Mar 2025 · 7 likes Biased agonism has been discussed here with more heat than it deserves, mostly because two definitions have been in play the whole time.
Charge states for a 4 kDa peptide, worked through Replied, post #2 · Analytics › Mass spectrometry · 1 Mar 2025 · 8 likes Answering the question the opening post raises rather than the one it answers. Resolution and mass accuracy are different specifications. An instrument can resolve two…
A 10 mg vial reconstituted three different ways, compared — the long version Replied, post #6 · Practice › Reconstitution · 30 Jan 2025 · 5 likes The best check on any reconstitution calculation is to do it twice by two different routes — mass per volume, then volume per dose — and see whether they agree. They…
When "no data" is the complete and final answer Replied, post #73 · Compounds › Other compounds · 23 Jan 2025 · 1 like Fragment compounds — where the material is part of a larger natural protein — should be identified by sequence rather than by name, because the naming in this space is…
What the published dose-response for semaglutide actually looks like above 2.4 mg — a… Replied, post #35 · Compounds › Semaglutide · 22 Jan 2025 · 0 likes Adding what did not work for me on published dose-response for semaglutide, since the failures never get written up and they are half the useful information.
Fixed versus detachable needles: the trade-offs Replied, post #64 · Devices › Syringes & needles · 22 Dec 2024 · 5 likes Post #60 and I disagree about the size of the effect, not about the direction. I have three months of notes on fixed versus detachable needles and the honest summary is…
Injection-site reactions: describing them precisely enough to be useful Replied, post #69 · Practice › Side effects · 13 Dec 2024 · 6 likes On post #66 — agreed on the reasoning, with one qualification. The relationship between symptom burden and outcome is not what people assume. Feeling worse is not…
Reading a preclinical wound-healing model and its relevance to a human tendon Replied, post #137 · Compounds › Repair & healing peptides · 24 Nov 2024 · 0 likes Filing a mild objection to the consensus on reading a preclinical wound-healing model. Mild because I might be wrong; an objection because nobody has addressed the case…
Meeting a protein target on a suppressed appetite — does this still hold? Replied, post #18 · Nutrition & Training › Protein & intake · 23 Nov 2024 · 0 likes Fibre and fluid tend to fall alongside protein when intake drops, and the constipation reported here follows from that as much as from the mechanism.
Requesting a page: what makes a good request — what changed since Replied, post #41 · Documentation › Wiki requests · 10 Oct 2024 · 0 likes Review cadence should be part of the proposal. A page about a fast-moving area needs a shorter cycle and somebody willing to honour it. This is the version I would want…
Second pass at: A field-by-field walk through a certificate of analysis Replied, post #58 · Analytics › COA interpretation · 18 Sep 2024 · 17 likes Practical experience of field-by-field walk through a certificate, offered as one case with the conditions stated, not as a general finding. Conditions first, because…
When to suspect the method rather than the sample Replied, post #10 · Analytics › Method validation · 8 Sep 2024 · 1 like Post #6 put the caveat in the right place and I want to underline it. Range: the concentration range over which the method has been validated. Going outside the…
Hepatic effects of glucagon receptor agonism: the mechanistic worry Replied, post #9 · Compounds › Retatrutide · 29 Aug 2024 · 5 likes This follows post #8 rather than contradicting it. Taking hepatic effects of glucagon receptor seriously for a moment rather than deflecting: the honest position is…
Follow-up: Dead volume across syringe and needle combinations Replied, post #24 · Devices › Syringes & needles · 21 Aug 2024 · 25 likes Filter needles are for drawing from glass ampoules where particulate is a real risk. For a stoppered vial they add dead volume in exchange for very little.
Why pulsatile secretion matters for interpreting secretagogue claims — a second dataset Replied, post #6 · Compounds › Secretagogues & GH axis · 21 Aug 2024 · 0 likes Picking up post #3: that is the part I would want checked first. A note on how pulsatile secretion gets discussed rather than on pulsatile secretion itself: the…
Coming back to: Preparing for an appointment: one page, three questions Replied, post #24 · Clinical › Prescriber conversations · 21 Jul 2024 · 0 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…
Follow-up: Dead volume across syringe and needle combinations Replied, post #9 · Devices › Syringes & needles · 13 Jul 2024 · 0 likes Coming back to post #8, because the follow-up matters more than the original answer. Fixed versus detachable needles: insulin syringes usually have fixed needles (no…
The mass-error checker and its intended scope Replied, post #99 · Data & Tools › Calculators · 5 Jul 2024 · 15 likes Worth separating mass-error checker as a question about the compound from mass-error checker as a question about the documentation. They get answered by different…
How this community labels and discusses unrefereed work Replied, post #34 · Evidence › Preprints · 22 Jun 2024 · 21 likes Unrefereed work is not worthless and a great deal of it survives review substantially unchanged. That is the accurate framing and it is not a licence to treat it as…
Assessing a warm arrival: the decision process — one year on Replied, post #31 · Sourcing › Logistics · 29 May 2024 · 0 likes Taking post #28 at face value and following it one step further. Two sentences on Assessing a warm arrival and then I will stop, because the rest is speculation and the…