d.moreau

TL2 Regular · Lyon, FR

Careful reader, occasional poster. Mostly the storage and stability categories.

Joined 18 January 2025 · last posted 19h

79 posts, newest first. Showing up to 150.

Named, unnamed and unspecified impurities as regulatory categories — the long version Replied, post #119 · Analytics › Impurities & related substances · 27 Jul 2026 · 25 likes Post #115 and I disagree about the size of the effect, not about the direction. Disulfide formation: if a peptide contains cysteine, it can form disulfide bonds with…
A supplier who responds to a discrepancy with silence — what changed since Replied, post #88 · Sourcing › Red flags · 26 Jul 2026 · 3 likes Inconsistency across documents: a certificate stating one purity, a website claiming another, and a supplier's verbal representation claiming a third, all on the same…
What a reversed-phase purity number actually is Replied, post #95 · Analytics › HPLC & UHPLC · 26 Jul 2026 · 9 likes Confirming post #92 from a second method, which matters more than confirming it from a second person. On integration: where the baseline is drawn matters more than most…
Why the Start Here categories exist, and what they are not for Replied, post #20 · Start Here › Welcome · 21 Jul 2026 · 0 likes Adding a reference point for Start. Mine is a single case, collected without controls, and I am posting the method alongside it so it can be discounted appropriately.
Named, unnamed and unspecified impurities as regulatory categories — the long version Replied, post #98 · Analytics › Impurities & related substances · 21 Jul 2026 · 12 likes Scavengers and cleavage-cocktail residues can persist and appear as small early-eluting peaks. They are process-related rather than sequence-related, which is a useful…
What a reversed-phase purity number actually is Replied, post #74 · Analytics › HPLC & UHPLC · 20 Jul 2026 · 0 likes Gradient slope is the single biggest driver of apparent purity differences. A shallower gradient over a longer run resolves more impurities and gives a higher purity…
Here for the analytics and not much else Replied, post #61 · Lounge › Introductions · 20 Jul 2026 · 17 likes Welcome. Nobody will mind you asking something basic. The people most likely to answer are the ones who remember not knowing it. Correct me on the arithmetic if it is…
What consumer-accessible tests can and cannot determine — a second dataset Replied, post #102 · Analytics › Home & field testing · 19 Jul 2026 · 0 likes The right question for any home test is: what physical quantity does it measure, and what would have to be true for that quantity to answer your question? Most…
Common supplements people ask about, assessed one at a time Replied, post #26 · Practice › Interactions · 9 Jul 2026 · 0 likes The arithmetic in post #23 is right; the assumption feeding it is the part to check. SGLT2 inhibitors: frequently co-administered and relevant to renal and…
Here for the analytics and not much else Replied, post #3 · Lounge › Introductions · 6 Jul 2026 · 11 likes Welcome. Nobody will mind you asking something basic. The people most likely to answer are the ones who remember not knowing it.
What I would want from a home test that does not exist yet — what changed since Replied, post #78 · Analytics › Home & field testing · 3 Jul 2026 · 0 likes Sample handling matters: if a sample is contaminated or degraded before testing, the test gives you the result for the degraded sample, not for fresh material. That is…
A checklist for reading a certificate in under two minutes Replied, post #45 · Analytics › COA interpretation · 21 Jun 2026 · 8 likes Coming back to post #41, because the follow-up matters more than the original answer. Endotoxin testing is separate: a certificate of purity says nothing about…
[2026 update] Interpreting a result that disagrees with the supplier's certificate Replied, post #8 · Sourcing › Independent verification · 9 Jun 2026 · 2 likes VendorInvestigate: documentation and supplier-practice review. Reviews paperwork rather than vials. Tells you something about a supplier's systems but says nothing…
Research-use-only status: what it means legally and practically Replied, post #53 · Compounds › Other compounds · 5 Jun 2026 · 19 likes Thymosin alpha-1 has a regulatory history in several jurisdictions and a real clinical literature, which puts it in a different evidential category from most of its…
Does a peptide degrade silently, with no visual change? Replied, post #36 · Practice › Storage & stability · 28 May 2026 · 5 likes Where I part company with post #34, and it is a narrow parting. Clarity is a weak test. A solution can lose a significant fraction of its active content to degradation…
Two scans six weeks apart on different machines: a cautionary tale Replied, post #14 · Outcomes › Body composition · 8 May 2026 · 13 likes Photographs under fixed lighting and posture are a genuine record and are the hardest of these to standardise. I would be interested in a counterexample if anyone has…
Measurement error in home scales, with a worked standard deviation — the long version Replied, post #86 · Research Methods › Statistics · 23 Apr 2026 · 3 likes The bit of Measurement error in home scales that nobody enjoys is that the answer changes depending on what you are trying to decide with it. Say what the decision is…
Insomnia at a dose step: reported experiences — the long version Replied, post #12 · Wellbeing › Sleep · 16 Apr 2026 · 29 likes An update on my earlier Insomnia post: the pattern held for another six weeks and then stopped, which I did not predict and cannot explain.
Pre-registering a personal experiment, seriously — a second dataset Replied, post #53 · Research Methods › N-of-1 designs · 8 Apr 2026 · 3 likes Blinding yourself is harder than it sounds and is not impossible. Somebody else preparing labelled containers is the usual approach and it requires a second person you…
Sample size intuition for a personal experiment — does this still hold? Replied, post #10 · Research Methods › Statistics · 24 Mar 2026 · 0 likes Sample size intuition is one of those subjects where the general answer and the answer for a specific case diverge, and the thread will go in circles until someone says…
Second pass at: The topic list is dense — is that deliberate? Replied, post #104 · Meta › Site feedback · 19 Mar 2026 · 0 likes Noted, and thank you for writing it out rather than summarising it.
Introducing myself: pharmacist, sceptic, reluctant participant — one year on Replied, post #90 · Lounge › Introductions · 17 Mar 2026 · 1 like Nice to meet you. Say what you are interested in rather than what you do, if you would rather — plenty of people here are anonymous about their background and it costs…
[2026 update] What a purity-only report leaves out Replied, post #55 · Sourcing › Independent verification · 15 Mar 2026 · 2 likes Checked the purity-only claim against the primary source this morning. It survives, with a narrower scope than the version quoted here. Posting the narrower scope.
Reading an interaction checker output critically Replied, post #146 · Practice › Interactions · 14 Mar 2026 · 0 likes Post #143 is the version of this I will quote in future. One addition. Insulin and sulfonylureas are the interaction that the labelling in this class flags most…
Angle of injection and whether 90 degrees is always right Replied, post #114 · Practice › Administration · 10 Mar 2026 · 5 likes A new needle for each injection is not fussiness. A needle blunts on first use and a blunted needle is the reason the second injection hurts more than the first. The…
Molecular mass of semaglutide and why the figure differs between sources Replied, post #15 · Compounds › Semaglutide · 8 Mar 2026 · 24 likes Albumin binding is not a unique structural feature and nothing in the class lacks it, but the reversibility matters. Semaglutide binds albumin covalently through a…
[2026 update] Amylin and gastric emptying: overlapping mechanisms with incretins Replied, post #19 · Compounds › Cagrilintide & amylin analogues · 2 Mar 2026 · 7 likes Post #16 is right about the mechanism and I think understates the practical bit. Nausea profile of amylin analogues: the historical agent pramlintide required multiple…
[2026 update] Availability by country, dated, with primary sources Replied, post #32 · Access › International · 26 Feb 2026 · 10 likes Summaries lag badly in this area. Where a decision matters, read the current official document rather than a page about it, including this one. Adding a source would…
Why "dose equivalence" between different incretin analogues is a weak concept Replied, post #91 · Practice › Dosing & titration · 19 Feb 2026 · 21 likes Post #90 answers the question as asked. The question underneath it is different. Holding a dose indefinitely: the trials did not study indefinite holding at a…
Interpreting a result that disagrees with the supplier's certificate Replied, post #107 · Sourcing › Independent verification · 3 Feb 2026 · 31 likes An honest declaration on interpreting a result: I have a prior here and it is strong enough that you should weight what I say downward. Stating it rather than hiding it.
Anaesthesia and elective surgery: the aspiration question Replied, post #10 · Practice › Interactions · 31 Jan 2026 · 14 likes This is the first time the answer has come with its own limits attached. Appreciated.
Coming back to: Reconstitution volumes that produce round numbers, tabulated Replied, post #2 · Practice › Reconstitution · 20 Jan 2026 · 10 likes Write the reconstitution date and the concentration on the vial. Not on a note, on the vial. Every account here of a dosing error involving the wrong concentration…
Documentation that appears only after payment Replied, post #124 · Sourcing › Red flags · 1 Jan 2026 · 2 likes Where the same certificate image appears with different lot numbers, that is a documentation finding worth reporting with the images attached. Worth checking against a…
Second pass at: Fasting versus non-fasting and which tests care Replied, post #5 · Clinical › Bloodwork · 30 Dec 2025 · 8 likes Adding the boring version of Fasting versus non-fasting, because the interesting version keeps getting posted and the boring one is usually right. Check the ordinary…
Vomiting: when it is expected and when it is a reason to stop Replied, post #46 · Practice › Side effects · 28 Dec 2025 · 4 likes Coming back to post #42, because the follow-up matters more than the original answer. The published rates come from populations that were titrated on a defined schedule…
Interpreting a result that disagrees with the supplier's certificate Replied, post #52 · Sourcing › Independent verification · 22 Dec 2025 · 0 likes Interpreting a result: I have looked for the primary source twice and failed twice. Either it does not exist or it is somewhere I do not know to look, and I would like…
Common supplements people ask about, assessed one at a time — a second dataset Replied, post #19 · Practice › Interactions · 12 Dec 2025 · 4 likes Timing separation is the standard mitigation where absorption rate is the concern, and the interval that matters depends on the other drug rather than on this one. It…
How to read a forest plot, properly, from scratch Replied, post #66 · Evidence › Trials · 6 Dec 2025 · 0 likes Post #64 is the version of this I will quote in future. One addition. Absolute and relative effects answer different questions. Write down the event rate in each arm…
Why oral semaglutide needs an absorption enhancer at all Replied, post #53 · Compounds › Oral incretins · 26 Nov 2025 · 21 likes Taking post #50 at face value and following it one step further. Why an oral formulation is a formulation achievement: the molecule is the same but the tablet is novel.…
Specification in the result column: why that is a meaningful error Replied, post #75 · Analytics › COA interpretation · 18 Nov 2025 · 19 likes When method identifiers are missing: "reversed-phase HPLC" is less specific than "reversed-phase HPLC at 214 nm on a C18 column with a 10 to 40% acetonitrile gradient…
Pre-registering a personal experiment, seriously — a second dataset Started this topic · Research Methods › N-of-1 designs · 2 Nov 2025 · 8 likes Posting this under the heading it deserves: Pre-registering a personal experiment, seriously — a second dataset Everything below is what sits behind that. Posting a…
Coming back to: A community side-effect dataset, with its response rate and biases Replied, post #31 · Data & Tools › Datasets · 10 Oct 2025 · 0 likes Thank you — that answers what I came here to find out.
Aggregated purity results across four services, with caveats — a second dataset Replied, post #148 · Data & Tools › Datasets · 11 Sep 2025 · 13 likes Careful with the language on Aggregated purity results across four. "Not detected" and "not present" are different findings and the first is a statement about the method.
The most useful thing you learned here that was not the answer you came for — a second… Replied, post #26 · Lounge › Off topic · 8 Sep 2025 · 3 likes Digression worth the space: the archive is starting to be genuinely long. There are questions here whose good answer is four years old and still correct, and that only…
When a preprint is the best available evidence and we say so Replied, post #144 · Evidence › Preprints · 5 Sep 2025 · 1 like The documentation on preprint is better than this thread and I say that as someone who has posted in the thread.
Follow-up: What is genuinely unknown about long-term amylin agonism Replied, post #3 · Compounds › Cagrilintide & amylin analogues · 2 Sep 2025 · 10 likes Everything in the opening post holds. The case it does not cover is the one I have. Comparing an amylin analogue to an incretin agonist on weight change alone misses…
What pooling buys you and what it destroys Replied, post #12 · Evidence › Meta-analyses · 29 Aug 2025 · 0 likes Saving this. It is the version I will quote when the question comes round again.
Pinch or no pinch, and how needle length changes the answer Replied, post #37 · Practice › Administration · 28 Aug 2025 · 9 likes Building on post #36 rather than restating it. Injecting into an area that has become firm: lipohypertrophy — thickened fatty tissue from repeated injection in one area…
A request that was declined, and the reasoning — a second dataset Replied, post #11 · Documentation › Wiki requests · 6 Aug 2025 · 0 likes Suggesting content for a page: if you know a maintained page is missing something important, post a suggestion with specific content you think should be added. If that…
Coming back to: Sample size calculations, read backwards from the published number Replied, post #64 · Evidence › Trials · 28 Jul 2025 · 25 likes Practical answer on Sample size calculations, since the theoretical one is upthread: do the simplest check first, write down the result, and only then decide whether…
Follow-up: History of disordered eating and why it changes the conversation Replied, post #46 · Clinical › Special populations · 23 Jul 2025 · 23 likes Answering the question post #42 raises rather than the one it answers. The most useful reply I ever got about History of disordered eating was a request to state my…
Escalating every six weeks instead of four: what I observed over eight months — one year… Replied, post #38 · Practice › Dosing & titration · 1 Jul 2025 · 0 likes Adding the measurement that post #37 says would settle it. Nothing here is medical advice, and a titration question is one of the few where a prescriber can genuinely…
The C-cell question: rodent findings and their human context Replied, post #33 · Compounds › Semaglutide · 30 Jun 2025 · 7 likes Solutions of semaglutide can look faintly opalescent without anything being wrong. Visible particulate, fibres or frank cloudiness are a different observation entirely…
Comparators chosen for regulatory reasons rather than clinical ones — one year on Replied, post #64 · Evidence › Trials · 28 Jun 2025 · 0 likes Picking up post #63: that is the part I would want checked first. Practical answer on Comparators chosen for regulatory reasons, since the theoretical one is upthread:…
Area percent versus weight percent: the confusion that causes most arguments — what… Replied, post #3 · Analytics › HPLC & UHPLC · 22 Jun 2025 · 1 like Counterpoint on Area percent versus weight percent, offered without confidence: the same observation is consistent with a much duller explanation, and nobody has ruled…
The CagriSema phase 2 paper and what a fixed combination buys — the long version Replied, post #39 · Compounds › Cagrilintide & amylin analogues · 8 Jun 2025 · 1 like Reconstitution at higher concentrations is worth avoiding for aggregation-prone material. The published formulation work generally uses lower concentrations than people…
Coming back to: Getting a referral rather than a refusal Replied, post #26 · Clinical › Prescriber conversations · 3 Jun 2025 · 9 likes Answering the question post #25 raises rather than the one it answers. Careful with the language on Getting a referral. "Not detected" and "not present" are different…
Cost per milligram, computed honestly across formats — the long version Replied, post #120 · Access › Pricing · 30 May 2025 · 21 likes The arithmetic in post #117 is right; the assumption feeding it is the part to check. Insurance tier placement: a compound might be covered but on a higher tier (higher…
Second pass at: A history of disordered eating: proceeding carefully Replied, post #50 · Wellbeing › Mental health · 13 May 2025 · 0 likes Maintenance brings a different set of psychological questions from loss, and the discussion here is much thinner on that phase.
The CagriSema phase 2 paper and what a fixed combination buys Replied, post #32 · Compounds › Cagrilintide & amylin analogues · 19 Apr 2025 · 1 like The CagriSema phase 2 paper: a fixed combination of the two components in one weekly injection. The trade-off of a fixed combination is that you cannot titrate the…
Carryover and the ghost peak from last week's standard Replied, post #27 · Analytics › HPLC & UHPLC · 4 Apr 2025 · 0 likes Detection wavelength: 214 nm detects the peptide bond and is relatively insensitive to composition. 280 nm detects aromatic residues and is strongly…
Tirzepatide in type 2 diabetes: the SURPASS programme, summarised honestly Replied, post #47 · Compounds › Tirzepatide · 26 Mar 2025 · 0 likes SURPASS-2 compared tirzepatide with semaglutide 1.0 mg, the licensed diabetes dose at that time. It did not compare with semaglutide 2.4 mg, the highest approved dose.…
Oxidation and deamidation mass shifts, tabulated Replied, post #70 · Analytics › Mass spectrometry · 11 Mar 2025 · 0 likes Resolution and mass accuracy are different specifications. An instrument can resolve two species and still assign their masses imprecisely, and the reverse is also…
Journal club: SURMOUNT-OSA and a hard endpoint in a soft field Replied, post #15 · Evidence › Journal club · 27 Feb 2025 · 0 likes Post #13 and I disagree about the size of the effect, not about the direction. What I would tell a new member reading about SURMOUNT-OSA for the first time: the…
Second pass at: Certificates issued by the seller versus by a laboratory Replied, post #63 · Analytics › COA interpretation · 26 Jan 2025 · 4 likes A chromatogram supplied as a small image is legible for peak shape and not for baseline detail. That is enough to sanity-check an integration and not enough to…
When "no data" is the complete and final answer Replied, post #64 · Compounds › Other compounds · 12 Jan 2025 · 0 likes Melanocortin agonists: mechanism involves the melanocortin-4 receptor pathway that regulates appetite. The documented adverse profile includes blood pressure elevation…
Revisiting: What a well-designed human trial of a secretagogue would look like Replied, post #23 · Compounds › Secretagogues & GH axis · 9 Jan 2025 · 4 likes A mass result for a short peptide is more discriminating than for a long one, because a single residue difference is a larger proportion of the total. That makes…
Follow-up: Individual participant data versus aggregate data Replied, post #21 · Evidence › Meta-analyses · 8 Jan 2025 · 0 likes Individual participant data versus aggregate: I have looked for the primary source twice and failed twice. Either it does not exist or it is somewhere I do not know to…
Reading a preclinical wound-healing model and its relevance to a human tendon Replied, post #102 · Compounds › Repair & healing peptides · 20 Nov 2024 · 9 likes The absence of human trials means there is no established dose, no established interval and no established duration. Protocols circulating in this space are convention…
Revisiting: Moderation log format change Replied, post #33 · Meta › Announcements · 19 Nov 2024 · 9 likes The most useful reply I ever got about Moderation log format change was a request to state my units. It sounds like pedantry and it has saved me twice.
Telehealth prescribing models in the US Replied, post #5 · Regional › North America · 16 Sep 2024 · 0 likes What I want from this telehealth prescribing models thread is the list of things that would need to be true for the claim to hold. If we can write that list, we can…
The C-cell question: rodent findings and their human context — what changed since Replied, post #54 · Compounds › Semaglutide · 15 Sep 2024 · 2 likes Where the c-cell question discussion usually stalls is that nobody wants to say "I do not know" and everyone is willing to say "it varies". Those are the same sentence…
Pancreatitis history and the risk calculus — a second dataset Replied, post #7 · Safety › Contraindications · 13 Sep 2024 · 0 likes This settles it for me, at least until somebody posts a reason it should not.
Follow-up: Dead volume across syringe and needle combinations Replied, post #33 · Devices › Syringes & needles · 11 Sep 2024 · 1 like Barrel size determines resolution and nothing else. A 0.3 mL barrel and a 1 mL barrel deliver the same volume equally well; the smaller one lets you see what you are…
Converting between mg/mL and units per dose, both directions Replied, post #2 · Practice › Reconstitution · 22 Aug 2024 · 9 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. Happy to be…
Second pass at: Retatrutide dose escalation in the published trials Replied, post #126 · Compounds › Retatrutide · 24 Jul 2024 · 22 likes Mass and identity: a report on retatrutide should state the mass detected by LC-MS, not assume a theoretical mass. The theoretical mass is not published in…
Promotion criteria, and the one that stops most nominations Replied, post #13 · Documentation › Doc review · 6 Jul 2024 · 1 like I have been on both sides of the promotion criteria argument in this category within eighteen months, which should tell you how strong the evidence for either side is.
Two sessions a week versus four: what the evidence supports — a second dataset Replied, post #23 · Nutrition & Training › Resistance training · 2 Jul 2024 · 1 like Coming back to post #20, because the follow-up matters more than the original answer. Reduced appetite makes fuelling a session harder, and that is a practical problem…
Assessing a warm arrival: the decision process — one year on Replied, post #53 · Sourcing › Logistics · 30 May 2024 · 16 likes Two questions I would want answered before drawing anything from the Assessing a warm arrival data above: how were the cases selected, and what happened to the ones…