m.marchetti

TL2 · Kumasi

Contributes reviews on supplier material. Based in Kumasi.

Joined 18 June 2025 · last posted 7d

86 posts, newest first. Showing up to 150.

Reading a rodent study on a secretagogue without over-extrapolating — the long version Replied, post #53 · Compounds › Secretagogues & GH axis · 21 Jul 2026 · 0 likes Adding what did not work for me on Reading a rodent study, since the failures never get written up and they are half the useful information.
An 18-month record including the parts that went badly Replied, post #64 · Outcomes › Progress reports · 9 Jul 2026 · 4 likes Post #63 is right about the mechanism and I think understates the practical bit. I have no financial interest in anything named in this thread and I want to say so…
How much context is too much context in a first post? Replied, post #51 · Start Here › How to Ask · 8 Jul 2026 · 0 likes Asking a follow-up: new topic or reply in the old one? If the answer depends on the previous post, reply. If it is a question that makes sense without the previous…
Prescription requirements and telehealth models — a second dataset Replied, post #90 · Sourcing › Regulatory · 3 Jul 2026 · 3 likes One caution on Prescription requirements and telehealth models: everything above assumes the underlying documentation is what it claims to be. That assumption is doing…
Immortal time bias in a claims-database study — one year on Replied, post #3 · Evidence › Study critique · 1 Jul 2026 · 0 likes Second-hand on Immortal time bias, so weight it accordingly — someone whose method I trust told me this and I have not verified it myself.
Request: a per-category review queue Replied, post #62 · Meta › Feature requests · 27 Jun 2026 · 0 likes Understood. Thank you for being specific about the limits of it.
Why we ask for units every single time, with three examples of what goes wrong Replied, post #69 · Start Here › How to Ask · 25 Jun 2026 · 23 likes Adding the measurement that post #66 says would settle it. Arithmetic questions: write out the steps. "I have a 10 mg vial, I added 2 mL, I want a 0.25 mg dose, and I…
Tracking intake honestly when appetite is absent Replied, post #65 · Nutrition & Training › Protein & intake · 19 Jun 2026 · 5 likes Published guidance on protein during weight loss is reasonably consistent and is easy to find, which makes this one of the better-evidenced practical questions here. I…
Comparing prices across jurisdictions without misleading yourself Replied, post #82 · Access › Pricing · 15 Jun 2026 · 20 likes What I can speak to on comparing prices across jurisdictions is narrow, so I will keep it narrow rather than generalising from it. Beyond that boundary I do not know.
About the Impurities & related substances category Replied, post #7 · Analytics › Impurities & related substances · 10 Jun 2026 · 13 likes Related substances: compounds chemically related to the target peptide but not the target peptide itself. The standard method separates them and reports them as area…
Coming back to: Specificity, linearity, accuracy, precision, range, robustness — with… Replied, post #45 · Analytics › Method validation · 7 Jun 2026 · 0 likes Appreciated. The plain phrasing does more work here than a longer post would.
Coming back to: Solubility limits and what a cloudy solution is telling you Replied, post #28 · Pharmacology › Formulation chemistry · 3 Jun 2026 · 17 likes Osmolality of a home-reconstituted preparation is whatever the diluent makes it, and nobody is measuring it. In practice at these volumes it is a comfort question.
Semaglutide and gastric emptying — the mechanism behind most of the side-effect profile Replied, post #46 · Compounds › Semaglutide · 31 May 2026 · 5 likes Injection site does not appear to matter much for semaglutide exposure. The published comparisons of abdomen, thigh and upper arm found differences small enough to be…
Reading a trial's population section before its results Replied, post #69 · Evidence › Trials · 30 May 2026 · 16 likes Discontinuation handling is the methodological detail that most changes a result and gets the least attention. Read how missing data was imputed before reading the…
How to ask a question when you cannot say why you are asking it Started this topic · Start Here › How to Ask · 25 May 2026 · 12 likes Asking directly, because I could not find a straight answer: How to ask a question when you cannot say why you are asking it Question in the title. Context below, and I…
A widely repeated interaction claim that turns out to be unsupported — what changed since Replied, post #39 · Practice › Interactions · 7 May 2026 · 0 likes Narrowing post #36, because the general version has more than one answer. Anything that also slows gut motility compounds the same mechanism. That is a plausibility…
Dizziness on standing and the electrolyte explanation — does this still hold? Replied, post #76 · Practice › Side effects · 4 May 2026 · 33 likes Reading back through the Dizziness on standing threads from last year, the same three questions come up every time and only one of them has ever been answered properly.…
Stepping down deliberately, and how to do it without losing progress Replied, post #94 · Practice › Dosing & titration · 18 Apr 2026 · 23 likes How the published trials escalated: they used specific step sizes and intervals. The STEP programme used a particular cadence; the SURPASS and SURMOUNT programmes used…
Coming back to: Time to steady state after a dose increase Replied, post #32 · Pharmacology › Pharmacokinetics · 14 Apr 2026 · 0 likes Area under the curve is the exposure measure that matters for most effects in this class. Peak concentration matters more for tolerability. Stating my assumptions…
Grapefruit: why this class is not the class that cares Replied, post #122 · Practice › Interactions · 5 Apr 2026 · 2 likes On grapefruit: the maintained page in the documentation commons covers the general case with citations and a review date, which is more reliable than any reply here…
Pharmacy supply in the UK and the questions you will be asked Replied, post #92 · Regional › UK & Ireland · 26 Mar 2026 · 0 likes Importing for personal use: importing a prescription-only medicine without a prescription is not lawful. Material sold as research-use-only is not a licensed medicine…
Second pass at: Identical chromatograms across two different lots Replied, post #64 · Sourcing › Red flags · 14 Mar 2026 · 4 likes Answering the question post #60 raises rather than the one it answers. The bit of Identical chromatograms that nobody enjoys is that the answer changes depending on…
Second pass at: Submitting a sample: the process end to end Replied, post #11 · Sourcing › Independent verification · 2 Mar 2026 · 30 likes Post #10 is the version of this I will quote in future. One addition. One caution on Submitting a sample: everything above assumes the underlying documentation is what…
Storing lyophilised material long term: what governs the shelf life Replied, post #87 · Practice › Storage & stability · 2 Mar 2026 · 15 likes The confident answers on storing lyophilised material long term and the well-sourced answers are not the same answers, which is the most useful thing I have learned…
Journal club: PIONEER 6 as a safety trial Replied, post #18 · Evidence › Journal club · 25 Feb 2026 · 1 like Confirming post #16 from a second method, which matters more than confirming it from a second person. STEP 1 (N Engl J Med 2021): The pivotal obesity trial for…
Measurement error in home scales, with a worked standard deviation — the long version Replied, post #36 · Research Methods › Statistics · 20 Feb 2026 · 0 likes Rounding and significant figures carry information about precision. A figure quoted to four significant figures from a method with two per cent variability is…
"Greater than or equal to 99%" as a specification rather than a result Replied, post #127 · Analytics › COA interpretation · 7 Feb 2026 · 0 likes What fields matter on a certificate: lot number matching the vial, test date, the analytical method stated specifically, the measured result as a number, and the…
[2026 update] Publication patterns in the BPC-157 literature, examined Replied, post #8 · marked as the solution · Compounds › Repair & healing peptides · 2 Feb 2026 · 12 likes Post #5 answers the question as asked. The question underneath it is different. Dose-response is unstudied in humans for essentially everything in this family, which…
Dead volume across syringe and needle combinations Replied, post #64 · Devices › Syringes & needles · 1 Feb 2026 · 0 likes I read post #62 twice before replying, because I had assumed the opposite. The most useful thing anyone has posted about dead volume across syringe in this category was…
Adolescents: a distinct evidence base — one year on Replied, post #55 · Clinical › Special populations · 18 Jan 2026 · 0 likes The reason Adolescents is hard to answer is that the obvious measurement and the relevant quantity are not the same thing, and substituting one for the other is silent.
[2026 update] Reading a supplementary appendix and finding the interesting part Replied, post #12 · Evidence › Trials · 16 Jan 2026 · 7 likes Agreed on Reading a supplementary appendix, with one qualification that I think matters. The reasoning holds for the case as described. Change the starting assumption…
Coming back to: Washout: how long is long enough, and for what purpose Replied, post #8 · Pharmacology › Pharmacokinetics · 4 Jan 2026 · 19 likes Helpful, and easy to find again, which is half of what a good reply is.
Specification in the result column: why that is a meaningful error Replied, post #99 · Analytics › COA interpretation · 3 Jan 2026 · 15 likes A certificate of analysis is a statement by its issuer that a defined test was performed on a defined lot and produced a defined result. That is all it is, and it is…
Vomiting: when it is expected and when it is a reason to stop Replied, post #36 · Practice › Side effects · 27 Dec 2025 · 10 likes The relationship between symptom burden and outcome is not what people assume. Feeling worse is not evidence of a larger effect and feeling nothing is not evidence of…
When a dose reduction is the correct response to a side effect — a second dataset Replied, post #3 · Practice › Dosing & titration · 15 Dec 2025 · 0 likes Thank you — that answers what I came here to find out.
[2026 update] How much of the diluent volume the powder itself displaces Replied, post #99 · Practice › Reconstitution · 27 Nov 2025 · 3 likes A 10 mg vial reconstituted three different ways: 1 mL diluent gives 10 mg/mL, 2 mL gives 5 mg/mL, 4 mL gives roughly 2.5 mg/mL. The arithmetic is the same; the…
Temperature loggers worth the money — the long version Replied, post #81 · Devices › Cold chain · 25 Nov 2025 · 27 likes Temperature loggers worth the money would be much easier to settle if anyone reported the denominator. Almost nobody reports the denominator.
Older adults, sarcopenia risk, and the trade-off nobody quantifies — the long version Replied, post #53 · Clinical › Special populations · 18 Nov 2025 · 2 likes Counterpoint on Older adults, offered without confidence: the same observation is consistent with a much duller explanation, and nobody has ruled the dull one out.
Revisiting: GLP-1 receptor distribution: central and peripheral Replied, post #60 · Pharmacology › Receptor biology · 1 Nov 2025 · 0 likes In vitro potency and clinical potency are related by a long chain of assumptions. A compound more potent at the receptor is not necessarily more effective at a…
SURMOUNT-4 and what withdrawal data does and does not tell an individual — one year on Replied, post #78 · Compounds › Tirzepatide · 22 Oct 2025 · 12 likes An honest declaration on SURMOUNT-4: I have a prior here and it is strong enough that you should weight what I say downward. Stating it rather than hiding it.
What a confidence interval means, from scratch — the long version Replied, post #7 · Research Methods › Statistics · 15 Oct 2025 · 0 likes Practical note on confidence interval: 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…
The most useful thing you learned here that was not the answer you came for — a second… Replied, post #96 · Lounge › Off topic · 14 Oct 2025 · 6 likes Adding thanks rather than a view. I do not have a view worth the space.
When to stop reading forums, including this one Replied, post #23 · Wellbeing › Mental health · 8 Sep 2025 · 0 likes Worth separating two things that post #21 runs together. Nothing here is medical advice and several members in this subcategory say plainly that they are describing…
Coming back to: Sample size calculations, read backwards from the published number Replied, post #88 · Evidence › Trials · 7 Sep 2025 · 0 likes One more thing on Sample size calculations that took me far too long to see: the two figures people quote are not measuring the same quantity. Once you notice that, the…
Reading a supplier's product description as a marketing document Replied, post #66 · Compounds › Other compounds · 4 Sep 2025 · 19 likes Why catalogue breadth is not evidence of anything: a supplier listing 500 compounds does not make the 450 untested ones likely to work. It makes them untested compounds…
An emergency department visit, described afterwards Replied, post #59 · Safety › Adverse events · 27 Aug 2025 · 20 likes Medullary thyroid carcinoma is the reason these compounds are contraindicated in people with personal or family history of MTC or multiple endocrine neoplasia type 2.…
BPC-157: what the rodent literature actually shows, and what it does not Replied, post #35 · Compounds › Repair & healing peptides · 26 Aug 2025 · 21 likes Confirming post #34 from a second method, which matters more than confirming it from a second person. Posting my BPC-157 numbers with the method attached so they can be…
[2026 update] What we do not know about retatrutide, listed explicitly Replied, post #49 · Compounds › Retatrutide · 15 Aug 2025 · 0 likes Post #47 answers the question as asked. The question underneath it is different. Retatrutide is investigational. Anything obtained outside a trial is by definition…
How to research a compound with no human data without deceiving yourself Replied, post #69 · Compounds › Other compounds · 2 Aug 2025 · 10 likes Thank you for the correction. I would rather find out here than later.
Follow-up: Why the titration planner refuses to produce a schedule below a floor Replied, post #60 · Data & Tools › Calculators · 23 Jul 2025 · 17 likes Dose equivalence calculator: compounds have different potencies. The calculator is provided with a caveat: "equivalence" is not precise and individual response varies.…
Coming back to: Nausea profile of amylin analogues compared with GLP-1 agonists Replied, post #50 · Compounds › Cagrilintide & amylin analogues · 11 Jul 2025 · 9 likes The version of Nausea profile of amylin analogues that I was taught turned out to be a teaching simplification. Useful, and not true in the way I had assumed it was.
Whether an aggregate is worth publishing at all: a disputed topic Replied, post #25 · Data & Tools › Datasets · 5 Jul 2025 · 26 likes That is the distinction I keep failing to hold on to. Written down now.
Revisiting: Filter needles: when they help and what they cost you Replied, post #31 · Devices › Syringes & needles · 26 Jun 2025 · 0 likes Needle gauge: smaller numbers (30G) are finer and less painful. Larger numbers (25G) are courser. For subcutaneous injection, 27-30G is typical. Finer needles take…
The CagriSema phase 2 paper and what a fixed combination buys — the long version Replied, post #127 · Compounds › Cagrilintide & amylin analogues · 17 Jun 2025 · 29 likes Reading the phase 2 paper: it establishes tolerability and efficacy in a selected population on a defined dose escalation. It does not establish the lowest effective…
Interpreting a composition change that is within the error bars Replied, post #4 · Outcomes › Body composition · 15 Jun 2025 · 16 likes On the opening post — agreed on the reasoning, with one qualification. Counterpoint on interpreting a composition change, offered without confidence: the same…
The CagriSema phase 2 paper and what a fixed combination buys — the long version Replied, post #83 · Compounds › Cagrilintide & amylin analogues · 13 Jun 2025 · 24 likes Offering a way to settle CagriSema phase 2 paper rather than another opinion about it. Two measurements, taken the same way, a fortnight apart. If the difference is…
Anxiety in the first weeks: drug, situation, or both Replied, post #85 · Wellbeing › Mental health · 7 May 2025 · 0 likes The arithmetic in post #82 is right; the assumption feeding it is the part to check. Social and relationship impacts: weight change affects how others perceive and…
Delayed gastric emptying and oral medication absorption: which drugs matter Replied, post #73 · Practice › Interactions · 5 May 2025 · 2 likes The most useful reply I ever got about delayed gastric emptying and oral was a request to state my units. It sounds like pedantry and it has saved me twice.
When a tidy document is a signal and when it is decoration Replied, post #3 · Analytics › COA interpretation · 28 Apr 2025 · 5 likes A document you have to ask for and receive within a working day tells you the records exist and are findable. That is a real property of an operation and it is worth…
Journal club: SURMOUNT-1, read without the press release Replied, post #103 · Evidence › Journal club · 24 Apr 2025 · 11 likes On SURMOUNT-1 the community has more anecdote than the confidence in this thread implies, and I include my own contribution in that.
Reading order for a first week here, and what to skip until later Replied, post #98 · Start Here › Welcome · 24 Apr 2025 · 12 likes Marked solutions are the site's way of saying that someone asked a good question and someone else gave an answer that actually worked. It is not a competition and it…
Why cagrilintide alone is discussed so much less than in combination Replied, post #96 · Compounds › Cagrilintide & amylin analogues · 2 Apr 2025 · 0 likes Comparing an amylin analogue to an incretin agonist on weight change alone misses that they were developed to be used together rather than instead of each other.
Preservatives: function, testing, and limits Replied, post #24 · Pharmacology › Formulation chemistry · 25 Mar 2025 · 0 likes Narrowing post #23, because the general version has more than one answer. The honest answer on preservatives is that it depends, and the useful part is the list of what…
Counter-ion form: the field almost nobody reports — one year on Replied, post #85 · Analytics › COA interpretation · 15 Mar 2025 · 1 like Narrowing post #82, because the general version has more than one answer. The thing about Counter-ion form that took me longest to accept is that a plausible mechanism…
Biased agonism: a real phenomenon, an over-used explanation Replied, post #70 · Pharmacology › Receptor biology · 10 Mar 2025 · 5 likes Coming back to post #68, because the follow-up matters more than the original answer. Since biased agonism keeps coming up, it should probably be a maintained page…
Counter-ion form: the field almost nobody reports — one year on Replied, post #64 · Analytics › COA interpretation · 9 Mar 2025 · 13 likes I had written a reply contradicting post #62 and deleted it. Here is what survived. A methods point on Counter-ion form rather than a substantive one: if the comparison…
Levothyroxine timing: a real interaction with a simple fix Replied, post #21 · Practice › Interactions · 11 Jan 2025 · 18 likes Alcohol is not contraindicated in the labelling and it does irritate a stomach that is already emptying slowly. There is no published interaction study, and the…
When to suspect the method rather than the sample Replied, post #60 · Analytics › Method validation · 3 Jan 2025 · 0 likes Limits of detection and quantitation: LOD is the lowest concentration that produces a signal above background. LOQ is the lowest concentration at which the method meets…
A page that has drifted out of date and needs a maintainer Replied, post #46 · Documentation › Wiki requests · 1 Jan 2025 · 33 likes Name a willing maintainer in the request. Point three of the criteria stops more nominations than the other three combined. Filing this under things that are true until…
Revisiting: What a well-designed human trial of a secretagogue would look like Replied, post #11 · Compounds › Secretagogues & GH axis · 31 Dec 2024 · 20 likes Hexarelin and the earlier peptidyl secretagogues have more published human data than the newer ones and a less favourable profile, which is worth knowing before…
Journal club: SUSTAIN 6 and its retinopathy signal — does this still hold? Replied, post #18 · Evidence › Journal club · 26 Dec 2024 · 0 likes SUSTAIN 6 was covered in the wiki last year and the page has a review date on it, which is a better starting point than my memory of a thread.
What we do not know about retatrutide, listed explicitly Replied, post #30 · Compounds › Retatrutide · 23 Dec 2024 · 2 likes Heart rate increased in a dose-dependent way in the phase 2 work. That is not a footnote — it is one of the specific things phase 3 exists to characterise, and it is…
Checking someone else's arithmetic: a worked example thread Replied, post #9 · Practice › Reconstitution · 22 Dec 2024 · 0 likes Preservative effectiveness is tested against a defined microbial challenge under defined conditions. It is not a licence to treat an entered vial as sterile…
Persistent vomiting and the threshold for seeking help — one year on Started this topic · Safety › Adverse events · 17 Dec 2024 · 57 likes Persistent vomiting and the threshold for seeking help — one year on Writing it up because I had to work it out twice and would rather nobody else did. I would like to…
Coming back to: When to suspect the method rather than the sample Replied, post #55 · Analytics › Method validation · 10 Dec 2024 · 3 likes A method transferred between laboratories needs a demonstration that it performs equivalently, not just a document describing it. Transfer is where a great many…
Follow-up: Where the four-week escalation interval comes from, and what it is not Replied, post #117 · Practice › Dosing & titration · 2 Dec 2024 · 3 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.…
Transit times by route, from a logged dataset — the long version Replied, post #31 · Sourcing › Logistics · 20 Nov 2024 · 1 like Documentation correct at first presentation is the actual explanation for a transit time that otherwise looks optimistic. Adding a source would improve this post and I…
Research-use-only status: what it means legally and practically — a second dataset Replied, post #13 · Compounds › Other compounds · 3 Nov 2024 · 0 likes Narrowing post #12, because the general version has more than one answer. Melanotan II is a non-selective melanocortin agonist, which is why its effects are not…
Chronic kidney disease and the FLOW result — a second dataset Replied, post #2 · Clinical › Comorbidities · 31 Oct 2024 · 1 like The opening post is the version of this I will quote in future. One addition. Multiple comorbidities: a person with diabetes, kidney disease, and cardiovascular disease…
Revisiting: Melanocortin agonists: mechanism and the documented adverse profile Replied, post #70 · Compounds › Other compounds · 24 Oct 2024 · 19 likes I disagree with the framing of Melanocortin agonists above, and I think it is a substantive disagreement rather than a terminological one. Setting out why, so it can be…
Revisiting: Moderation log format change Replied, post #4 · Meta › Announcements · 22 Oct 2024 · 0 likes I keep a log for Moderation log format change specifically because my memory of it turned out to be systematically wrong in one direction. Six weeks of notes cost…
Revisiting: How to bring a laboratory report to an appointment usefully Replied, post #126 · Clinical › Bloodwork · 20 Oct 2024 · 0 likes The honest answer on bring a laboratory is that it depends, and the useful part is the list of what it depends on. Four items, in rough order of how much they matter.…
Melanocortin agonists: mechanism and the documented adverse profile Replied, post #6 · Compounds › Other compounds · 29 Sep 2024 · 2 likes Melanocortin agonists: mechanism involves the melanocortin-4 receptor pathway that regulates appetite. The documented adverse profile includes blood pressure elevation…
Coming back to: Purity assay versus content assay: two different numbers Replied, post #64 · Analytics › COA interpretation · 13 Aug 2024 · 1 like Taking post #63 at face value and following it one step further. Purity assay versus content assay looks different depending on whether you are reading the primary…
Second pass at: Retatrutide dose escalation in the published trials Replied, post #40 · Compounds › Retatrutide · 18 Jul 2024 · 0 likes Post #36 put the caveat in the right place and I want to underline it. Reporting rather than recommending, on Retatrutide dose escalation. What happened is above.…
Follow-up: A partial dose because the pen emptied mid-injection Replied, post #7 · Practice › Administration · 18 Jul 2024 · 10 likes Taking post #4 at face value and following it one step further. Where the partial dose because the pen reasoning breaks down for me is the step from the group result to…