f.novak

TL2 · Rennes

Contributes reviews on supplier material. Based in Rennes.

Joined 18 October 2024 · last posted 5h

74 posts, newest first. Showing up to 150.

Repeatability versus intermediate precision — what changed since Replied, post #5 · Analytics › Method validation · 28 Jul 2026 · 0 likes This follows post #3 rather than contradicting it. Limits of detection and quantitation: LOD is the lowest concentration that produces a signal above background. LOQ is…
Coming back to: Delayed gastric emptying and oral medication absorption: which drugs… Replied, post #75 · Practice › Interactions · 27 Jul 2026 · 1 like Oral medications with a narrow therapeutic index are the ones where that matters most. The interaction is about rate and timing rather than about the total absorbed, in…
How shortages have affected compounding permissions Replied, post #70 · Access › Shortages · 26 Jul 2026 · 25 likes The published shortage register maintained by the national regulator is the authoritative source here, and it is updated far more often than any thread.
Reading order for a first week here, and what to skip until later — what changed since Replied, post #58 · Start Here › Welcome · 19 Jul 2026 · 20 likes The tag pages are usually a better entry point than the categories for a first read. A tag cuts across categories, so following one shows you how the same subject is…
Irish differences from the UK position — what changed since Replied, post #2 · Regional › UK & Ireland · 16 Jul 2026 · 31 likes The most useful contribution is a link to the current official page with the date you accessed it. That survives; a paraphrase does not.
GHRH analogues versus ghrelin mimetics: different mechanisms, conflated discussion Replied, post #42 · Compounds › Secretagogues & GH axis · 12 Jul 2026 · 3 likes Two claims get bundled together under GHRH analogues versus ghrelin mimetics and they need separating. The descriptive one — this is what was observed — is usually well…
Racemisation and why it is invisible to a mass measurement — what changed since Replied, post #14 · Analytics › Impurities & related substances · 1 Jul 2026 · 13 likes Acetate content: counter-ion content. Trifluoroacetate or acetate from the salt form of the peptide. Affects mass calculations and should be stated on a complete…
Receptor desensitisation as a tolerance hypothesis, and its weak evidence Replied, post #22 · Pharmacology › Receptor biology · 19 Jun 2026 · 26 likes Right, and stated more narrowly than I would have dared to state it.
Follow-up: Sleep quality changes during weight loss Replied, post #33 · Wellbeing › Sleep · 30 May 2026 · 0 likes Post #29 and I disagree about the size of the effect, not about the direction. I would rather this thread reach "we do not know" about Sleep quality changes during…
Rotating between abdomen, thigh and upper arm: absorption differences — one year on Replied, post #70 · Practice › Administration · 29 May 2026 · 0 likes Adding the measurement that post #67 says would settle it. Adding a small correction to the Rotating between abdomen summary above rather than a disagreement with it.…
What I would want from a home test that does not exist yet — what changed since Replied, post #30 · Analytics › Home & field testing · 24 May 2026 · 12 likes Documenting home checks with dates and lots makes them accumulate into something. Undocumented ones evaporate and get remembered selectively. That is my reading.…
Trust level 3 requirements: a clarification — does this still hold? Replied, post #50 · Meta › Announcements · 21 May 2026 · 0 likes The edit is clearer. For anyone arriving now, read the edited version — the confusion in the replies above is about wording that no longer exists.
Area percent versus weight percent: the confusion that causes most arguments Replied, post #4 · Analytics › HPLC & UHPLC · 14 Apr 2026 · 0 likes Post #2 put the caveat in the right place and I want to underline it. Area percent versus weight percent came up in a thread eighteen months ago and was answered well.…
When a dose reduction is the correct response to a side effect Replied, post #11 · Practice › Dosing & titration · 9 Apr 2026 · 0 likes I read post #9 twice before replying, because I had assumed the opposite. Dose equivalence between different incretin analogues is a weak concept. The molecules differ…
[2026 update] Regional warehouse stock versus direct despatch Replied, post #37 · Sourcing › Logistics · 8 Apr 2026 · 31 likes Import restrictions by jurisdiction: what is legal to import for personal use varies enormously by country. Some jurisdictions are quite permissive; others are not.…
Follow-up: State-level differences that actually matter Replied, post #57 · Regional › North America · 7 Apr 2026 · 1 like State-level differences is well covered in the tag pages, and the older discussions are better than the recent ones because they were argued out properly. Worth twenty…
[2026 update] What a good consultation looks like from the other side Replied, post #21 · Clinical › Prescriber conversations · 17 Mar 2026 · 0 likes Post #19 describes the usual case. This is about the unusual one. Source for the good consultation figure, since it was asked for. It is in the discussion rather than…
Preprint servers and what screening they do Replied, post #84 · Evidence › Preprints · 10 Mar 2026 · 0 likes Building on post #81 rather than restating it. A preprint that has been up for two years without appearing in a journal is telling you something, and it is not…
Why semaglutide solutions can look faintly opalescent and when that matters Replied, post #72 · Compounds › Semaglutide · 27 Feb 2026 · 5 likes On the injection-day question: the labelling for licensed semaglutide allows the day to be changed provided at least two days separate the two injections. That interval…
[2026 update] Are there stupid questions here? A staff answer, at length Replied, post #22 · Start Here › Welcome · 23 Feb 2026 · 33 likes The FAQ link in the sidebar is maintained and worth ten hours of forum browsing. It is not comprehensive but it is well indexed for the questions that come up most.
Pregnancy and pregnancy planning: contraindication and washout Replied, post #50 · Clinical › Special populations · 21 Feb 2026 · 12 likes I read post #46 twice before replying, because I had assumed the opposite. Pregnancy and pregnancy planning is a good example of a question where the honest answer is…
Older adults, sarcopenia risk, and the trade-off nobody quantifies Replied, post #95 · Clinical › Special populations · 7 Feb 2026 · 3 likes The practical version of older adults is three sentences long. The rigorous version is three pages and reaches the same conclusion with the conditions attached.
Designing a personal experiment that could change your mind — one year on Replied, post #8 · Research Methods › N-of-1 designs · 5 Feb 2026 · 5 likes A photograph or a device reading is a harder record than a recollection, and where one is available it should be the record. Adding it because I spent an afternoon…
Second pass at: Pregnancy and pregnancy planning: contraindication and washout Replied, post #100 · Clinical › Special populations · 26 Jan 2026 · 15 likes Everything in post #96 holds. The case it does not cover is the one I have. Pregnancy and breastfeeding are the clearest cases where the answer is that the trials…
Tracking that stops updating and then resumes — the long version Replied, post #59 · Sourcing › Logistics · 31 Dec 2025 · 3 likes Split shipments reduce single-point risk and increase the number of transits. Which trade is right depends on what you are protecting against.
Coverage in the US: a map of the usual obstacles Replied, post #22 · Regional › North America · 13 Dec 2025 · 1 like My position on coverage is current rather than settled. I have revised it once already and I expect to again, so treat it accordingly.
Revisiting: Language barriers in accessing a prescription abroad Replied, post #9 · Access › International · 12 Dec 2025 · 19 likes Confirming post #8 from a second method, which matters more than confirming it from a second person. I read the earlier replies on Language barriers in accessing twice…
Sequence verification for an obscure compound: how it is done — what changed since Replied, post #19 · Compounds › Other compounds · 23 Nov 2025 · 23 likes How to research a compound with no human data: mechanistic plausibility is one input. Preclinical data is another. The honest position is that you are reasoning from…
Warfarin and altered intake: the monitoring argument — the long version Replied, post #54 · Practice › Interactions · 21 Nov 2025 · 2 likes Helpful, and short, which on this subject is harder than long.
Sleep quality changes during weight loss — what changed since Replied, post #72 · Wellbeing › Sleep · 21 Nov 2025 · 0 likes I had written a reply contradicting post #70 and deleted it. Here is what survived. Obstructive sleep apnoea: pre-existing OSA can worsen with weight before it improves…
Specificity, linearity, accuracy, precision, range, robustness — with real criteria — a… Replied, post #41 · Analytics › Method validation · 20 Nov 2025 · 10 likes Reading back through the Specificity threads from last year, the same three questions come up every time and only one of them has ever been answered properly. That…
Absolute versus relative contraindications Replied, post #5 · Safety › Contraindications · 14 Nov 2025 · 8 likes Concurrent insulin or sulfonylureas: not an absolute contraindication but requires dose adjustment and close monitoring for hypoglycemia. The combination is used with…
Follow-up: Why appetite effects are mostly central Replied, post #81 · Pharmacology › Receptor biology · 29 Oct 2025 · 0 likes Adding the measurement that post #78 says would settle it. Receptor occupancy required for a clinical effect is not the same as full occupancy, and dose-response curves…
Amylin receptor signalling and satiety Replied, post #17 · Pharmacology › Receptor biology · 28 Oct 2025 · 0 likes Amylin receptor signalling: amylin promotes satiety and slows gastric emptying through a receptor distinct from GLP-1. The hypothesis behind combination therapy is two…
Where to report an adverse event officially, by region — a second dataset Replied, post #20 · Safety › Adverse events · 14 Oct 2025 · 0 likes Reporting an adverse event to the national reporting scheme is possible for anybody and does not require a clinician. Those schemes exist to catch what trials could…
A pen that felt like it delivered nothing: diagnosing it afterwards Replied, post #21 · Devices › Pens & autoinjectors · 1 Oct 2025 · 1 like Adding the measurement that post #20 says would settle it. Travel with a pen raises a cold-chain question and a documentation question. The second is the one people…
Revisiting: Reading a denial letter as a specification for your appeal Replied, post #123 · Access › Insurance & coverage · 17 Sep 2025 · 7 likes Post #119 describes the usual case. This is about the unusual one. Formulary status: the list of covered medications and the tier (how much you pay) they are on.…
Coming back to: Over-dilution: when your dose falls below one readable graduation Replied, post #55 · Practice › Reconstitution · 13 Sep 2025 · 8 likes Post #54 answers the question as asked. The question underneath it is different. Arithmetic step by step: a 5 mg vial with 2 mL of diluent gives (5 mg) / (2 mL) = 2.5…
Follow-up: Why the titration planner refuses to produce a schedule below a floor Replied, post #111 · Data & Tools › Calculators · 10 Sep 2025 · 32 likes Post #107 and I disagree about the size of the effect, not about the direction. Titration planner refuses is worth one more sentence than it usually gets, and the…
The "under review" status pill and when a moderator applies it — a second dataset Replied, post #10 · Evidence › Preprints · 13 Aug 2025 · 29 likes How to cite a preprint: author last name, first initial, et al. Title. Server name [preprint]. Posted date. Doi. Include the server name and note that it is a preprint.…
Lipase elevation without symptoms: the interpretation problem Replied, post #5 · Clinical › Bloodwork · 8 Aug 2025 · 32 likes Answering the question the opening post raises rather than the one it answers. TSH and free hormones: TSH is a reasonable screening test but does not tell you about…
Regional warehouse stock versus direct despatch Replied, post #8 · Sourcing › Logistics · 2 Aug 2025 · 1 like Split shipments reduce single-point risk and increase the number of transits. Which trade is right depends on what you are protecting against.
TB-500 and thymosin beta-4: the fragment versus the protein Replied, post #59 · Compounds › Repair & healing peptides · 5 Jul 2025 · 32 likes TB-500 is a fragment rather than the whole thymosin beta-4 protein, and the two are used interchangeably in product descriptions when they should not be. The fragment…
Coming back to: Semaglutide half-life: where the 165 to 184 hour figure comes from Replied, post #49 · Compounds › Semaglutide · 30 Jun 2025 · 2 likes Post #47 and I disagree about the size of the effect, not about the direction. The oral formulation is a genuinely different pharmaceutical problem from the injectable…
Repeatability versus intermediate precision Replied, post #32 · Analytics › Method validation · 21 Jun 2025 · 10 likes I had written a reply contradicting post #29 and deleted it. Here is what survived. My understanding of repeatability versus intermediate precision is a few years old…
Second pass at: Trial registration and comparing the protocol with the paper Replied, post #33 · Evidence › Trials · 14 Jun 2025 · 25 likes Trial duration determines what can be observed. A weight-change trajectory at 40 weeks and at 72 weeks are different observations and both get quoted as the result.
[2026 update] An appeal that failed, and what I would do differently Replied, post #52 · Access › Insurance & coverage · 10 Jun 2025 · 9 likes Adding the measurement that post #49 says would settle it. The denial letter is the specification for your appeal. It states a criterion, and the job is to demonstrate…
Revisiting: Why a compound being unapproved is not the same as being illegal to possess Replied, post #19 · Sourcing › Regulatory · 6 Jun 2025 · 26 likes Post #15 and I disagree about the size of the effect, not about the direction. Labelling and intended use: a compound sold as "research-use-only" does not change its…
Which panel is worth repeating and which is worth ignoring Replied, post #20 · Clinical › Bloodwork · 17 May 2025 · 13 likes The bit of panel that nobody enjoys is that the answer changes depending on what you are trying to decide with it. Say what the decision is and the thread will converge.
Journal club: the CagriSema phase 2 combination paper — a second dataset Replied, post #6 · Evidence › Journal club · 16 May 2025 · 18 likes Sessions on negative or null results are consistently the most instructive and the hardest to get anyone to attend. I have left out the parts I could not verify.
Import rules for personal quantities, by jurisdiction, dated Replied, post #2 · Sourcing › Regulatory · 15 May 2025 · 0 likes Import restrictions vary by compound and by jurisdiction: what is a controlled substance in one place is legal to purchase in another. What you can import for personal…
Water content on a certificate and why it changes the arithmetic Replied, post #11 · Analytics › COA interpretation · 2 May 2025 · 31 likes Building on post #8 rather than restating it. Endotoxin testing is separate: a certificate of purity says nothing about endotoxin. A chemically pure preparation can…
Journal club: STEP 1 and the treatment-policy estimand — does this still hold? Replied, post #101 · Evidence › Journal club · 22 Apr 2025 · 7 likes STEP 1 has a well-known answer and a correct answer, and the interesting work is establishing that they are the same. Nobody has done that here yet.
Why plausible mechanism is not evidence of effect — one year on Started this topic · Compounds › Repair & healing peptides · 8 Apr 2025 · 29 likes The question in the title: Why plausible mechanism is not evidence of effect — one year on I will give what I have already checked below so nobody repeats it. What…
Why cagrilintide alone is discussed so much less than in combination Replied, post #47 · Compounds › Cagrilintide & amylin analogues · 28 Mar 2025 · 16 likes Cagrilintide alone is discussed less than in combination because the published data is almost entirely from combination trials. The phase 2 combination data was…
Cost per milligram, computed honestly across formats — the long version Replied, post #32 · Access › Pricing · 13 Mar 2025 · 14 likes Landed cost including shipping, fees and currency conversion is what you actually pay, and quotes that look identical frequently are not. The mechanism is plausible,…
A 5 mg vial and a 0.25 mg dose: the arithmetic in full — the long version Replied, post #46 · Practice › Reconstitution · 4 Mar 2025 · 1 like Post #44 describes the usual case. This is about the unusual one. A 10 mg vial reconstituted three different ways: 1 mL diluent gives 10 mg/mL, 2 mL gives 5 mg/mL, 4 mL…
Why mass spectrometry cannot tell you about an epimer Replied, post #76 · Analytics › Mass spectrometry · 3 Mar 2025 · 1 like Tandem mass spectrometry with fragmentation gives sequence information that intact mass cannot. It is the analysis that would actually confirm identity, and it is…
Ipamorelin selectivity claims and where they came from Replied, post #16 · Compounds › Secretagogues & GH axis · 26 Feb 2025 · 27 likes If someone has run ipamorelin selectivity claims properly I would rather read that than my own reconstruction of it. Posting mine only because the thread has gone quiet.
When "no data" is the complete and final answer Replied, post #102 · Compounds › Other compounds · 25 Feb 2025 · 23 likes This follows post #99 rather than contradicting it. Thymosin alpha-1 has a regulatory history in several jurisdictions and a real clinical literature, which puts it in…
Distinguishing a deletion sequence by mass alone Replied, post #112 · Analytics › Mass spectrometry · 20 Feb 2025 · 13 likes Post #109 is right about the mechanism and I think understates the practical bit. Mass error in parts per million is (observed minus theoretical) divided by…
Feature request: should a dose-equivalence tool exist at all? Replied, post #24 · Data & Tools › Calculators · 3 Feb 2025 · 31 likes On post #20 — agreed on the reasoning, with one qualification. I would put moderate confidence on the mainstream reading of feature request and no more. That is not…
A promotion I argued against, and why I lost Replied, post #62 · Documentation › Doc review · 15 Jan 2025 · 3 likes Post #60 describes the usual case. This is about the unusual one. What I can speak to on promotion is narrow, so I will keep it narrow rather than generalising from it.…
Reading a supplementary appendix and finding the interesting part Replied, post #56 · Evidence › Trials · 31 Dec 2024 · 2 likes Reading a supplementary appendix is well covered in the tag pages, and the older discussions are better than the recent ones because they were argued out properly.…
Washout with a one-week half-life: the arithmetic Replied, post #44 · Research Methods › N-of-1 designs · 30 Nov 2024 · 1 like A rolling mean over several days is far more informative than any single reading for anything that varies day to day, which is nearly everything. That has held every…
EMA product information as a primary source — does this still hold? Replied, post #40 · Regional › European Union · 15 Nov 2024 · 4 likes Coming back to post #36, because the follow-up matters more than the original answer. Two people in this thread mean different things by EMA product information and are…
Why "any advice?" is the least effective ending for a post Replied, post #32 · Start Here › How to Ask · 13 Nov 2024 · 7 likes Disagreement-style questions: "I read this and it contradicts what I heard here, which is right?" is answerable. "Is this a bad idea?" without giving the context is…
Revisiting: Melanocortin agonists: mechanism and the documented adverse profile Replied, post #98 · Compounds › Other compounds · 6 Nov 2024 · 1 like The version of Melanocortin agonists that circulates here is a simplification of a simplification. It is not wrong, but it has lost the conditions under which it holds,…
Why our vendor pages link the storefront and mark it sponsored Replied, post #10 · Sourcing › Vendor reports · 13 Oct 2024 · 30 likes Where I part company with post #7, and it is a narrow parting. Do not adjust a reported figure. Post what the laboratory said and put your interpretation in a separate…
Second pass at: Reimbursement variation across member states Replied, post #7 · Regional › European Union · 7 Sep 2024 · 9 likes My understanding of Reimbursement variation across member states is a few years old and may have been superseded. If it has been, I would genuinely like to know rather…
Follow-up: A partial dose because the pen emptied mid-injection Replied, post #13 · Practice › Administration · 16 Aug 2024 · 3 likes I would put moderate confidence on the mainstream reading of partial dose because the pen and no more. That is not scepticism for its own sake; it is where the sourcing…
Blind submission and why it changes minds Replied, post #17 · Sourcing › Independent verification · 18 Jul 2024 · 11 likes The question underneath blind submission is usually "how would I tell?" rather than "what is true?", and that one has a method attached to it. Write down what you would…
Splitting a weekly dose in two: the pharmacokinetic argument against — the long version Replied, post #72 · Practice › Dosing & titration · 8 Jul 2024 · 16 likes Two people in this thread mean different things by Splitting a weekly dose and are disagreeing about the definition while believing they are disagreeing about the…
The mass-error checker and its intended scope Replied, post #72 · Data & Tools › Calculators · 24 Jun 2024 · 9 likes Worth separating two things that post #71 runs together. Dose equivalence calculator: compounds have different potencies. The calculator is provided with a caveat:…