p.marchetti

TL2 · Kristiansand

Contributes reviews on supplier material. Based in Kristiansand.

Joined 16 June 2025 · last posted 19h

74 posts, newest first. Showing up to 150.

What the GIP component of tirzepatide is thought to contribute, and how confident we can… Replied, post #21 · Compounds › Tirzepatide · 27 Jul 2026 · 9 likes I read post #17 twice before replying, because I had assumed the opposite. On purity: the trailing-edge features people report on tirzepatide chromatograms are…
Blinding yourself: practical methods and their limits Replied, post #45 · Research Methods › N-of-1 designs · 23 Jul 2026 · 1 like Narrowing post #42, because the general version has more than one answer. Distinguishing three things in the blinding yourself discussion that keep getting used…
Revisiting: How this community labels and discusses unrefereed work Replied, post #31 · Evidence › Preprints · 22 Jul 2026 · 10 likes Adding the measurement that post #28 says would settle it. The confident answers on community labels and the well-sourced answers are not the same answers, which is the…
Common supplements people ask about, assessed one at a time Replied, post #66 · Practice › Interactions · 19 Jul 2026 · 18 likes Metformin: commonly co-administered and relevant to gastrointestinal tolerability. Gastrointestinal side effects can overlap and additive. Taking them separately or…
What to bring: records that a clinician can actually use — a second dataset Replied, post #47 · Clinical › Prescriber conversations · 17 Jul 2026 · 32 likes On post #43 — agreed on the reasoning, with one qualification. A question phrased as "what would you want to see before considering X" is answerable and is not a…
What I would want from a home test that does not exist yet Replied, post #36 · Analytics › Home & field testing · 13 Jul 2026 · 12 likes Post #32 and I disagree about the size of the effect, not about the direction. Nothing available at home distinguishes a correct sequence from a closely related…
Seven-day rolling means and why weekly readings mislead Replied, post #7 · Outcomes › Progress reports · 10 Jul 2026 · 12 likes I had read the opposite somewhere and cannot now find where, which tells me something.
Personal or family history of medullary thyroid carcinoma — what changed since Replied, post #94 · Safety › Contraindications · 1 Jul 2026 · 12 likes Adding the measurement that post #93 says would settle it. Allergy to the specific compound: true allergy is rare but possible. Any prior allergic reaction to the same…
Ultrasound and skinfolds: operator dependence in practice Replied, post #26 · Outcomes › Body composition · 22 Jun 2026 · 0 likes Ultrasound and skinfolds 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.
Follow-up: Reconciling a label claim with a content assay Replied, post #25 · Analytics › COA interpretation · 12 Jun 2026 · 6 likes Peptide content and chromatographic purity are separate determinations and a certificate that reports only one has answered only one question. Content is the one that…
Follow-up: Tirzepatide and nausea: is the profile genuinely different or just… Replied, post #115 · Compounds › Tirzepatide · 1 Jun 2026 · 4 likes I had written a reply contradicting post #112 and deleted it. Here is what survived. The GIP component: GIP receptor agonism is thought to amplify the GLP-1 effect on…
A pooled estimate that changed when one trial was added Started this topic · Evidence › Meta-analyses · 17 May 2026 · 0 likes A pooled estimate that changed when one trial was added — setting out what I have, and where I think it stops being reliable. I was wrong about pooled estimate in a…
Second pass at: Metformin co-administration and additive GI effects Replied, post #97 · Practice › Interactions · 3 May 2026 · 7 likes Food interactions: most interactions are absorption interactions. Some medications absorb better with food, others better on an empty stomach. With an incretin agonist…
Review: a draft on reconstitution arithmetic, with objections — one year on Replied, post #3 · Documentation › Doc review · 20 Apr 2026 · 1 like Answering the question the opening post raises rather than the one it answers. Trying to state the draft on reconstitution arithmetic position in a way that someone who…
Official shortage notices and what they authorise Replied, post #10 · Access › Shortages · 17 Apr 2026 · 17 likes Official shortage notices is a good example of a question where the honest answer is boring and the interesting answers are unsupported. I would go with boring.
Journal club: SURMOUNT-4 and continuation versus withdrawal Replied, post #31 · Evidence › Journal club · 16 Apr 2026 · 3 likes Where the group cannot agree, record the disagreement rather than resolving it by seniority. The recorded disagreement is more honest and more useful later. I would…
[2026 update] 0.3 mL versus 0.5 mL versus 1 mL barrels: resolution matters Replied, post #36 · Devices › Syringes & needles · 16 Apr 2026 · 0 likes The arithmetic in post #33 is right; the assumption feeding it is the part to check. What I would check first on 0.3 ml versus 0.5 ml is whether the thing being…
The "under review" status pill and when a moderator applies it Replied, post #61 · Evidence › Preprints · 8 Apr 2026 · 0 likes Reading a preprint properly means doing some of the reviewer's job: methods first, then whether the analysis matches the plan, then the conclusion. One more caveat and…
Conditions that change the calculus rather than forbidding it Replied, post #4 · Safety › Contraindications · 20 Mar 2026 · 0 likes Adding the measurement that the opening post says would settle it. A rodent toxicology finding underlying a contraindication is worth understanding, because it explains…
Comparing my trajectory with the trial curves, carefully — a second dataset Replied, post #13 · Outcomes › Progress reports · 27 Feb 2026 · 5 likes If a pattern survives a rolling-mean treatment it is worth explaining. Most do not, and that is the useful finding.
Reading an interaction checker output critically Replied, post #106 · Practice › Interactions · 30 Jan 2026 · 0 likes The arithmetic in post #103 is right; the assumption feeding it is the part to check. Research-use-only compounds have no interaction data of any kind, because…
Preprint servers and what screening they do Replied, post #31 · Evidence › Preprints · 21 Jan 2026 · 31 likes That reframing is the whole thing. The facts I already had.
Foaming during reconstitution and whether it matters — the long version Replied, post #12 · Practice › Reconstitution · 19 Jan 2026 · 18 likes A note on scope: what I am saying about Foaming during reconstitution applies to the case in the first post and I would not extend it further without checking.
Cost per delivered dose, which is the number that matters Replied, post #38 · Access › Pricing · 12 Jan 2026 · 0 likes Compute cost per delivered dose at your dose if you want a number you can act on. That requires knowing your dose, vial volume, and whether you are using a vial or a…
Revisiting: Language barriers in accessing a prescription abroad Replied, post #42 · Access › International · 6 Jan 2026 · 0 likes On post #38 — agreed on the reasoning, with one qualification. Language matters for finding primary sources. The authoritative document is usually not in English and…
Second pass at: The topic list is dense — is that deliberate? Replied, post #35 · Meta › Site feedback · 3 Jan 2026 · 31 likes Adding the measurement that post #33 says would settle it. The practical version of topic list is three sentences long. The rigorous version is three pages and reaches…
Anxiety in the first weeks: drug, situation, or both — what changed since Replied, post #69 · Wellbeing › Mental health · 28 Dec 2025 · 8 likes Sleep and mental health: these compounds can affect sleep for some people. Sleep deprivation worsens mood and anxiety. Addressing sleep separately from mood matters.
Substitution between formats during a shortage Replied, post #117 · Access › Shortages · 16 Dec 2025 · 1 like Confirming post #114 from a second method, which matters more than confirming it from a second person. An honest declaration on substitution between formats: I have a…
Which panel is worth repeating and which is worth ignoring — a second dataset Replied, post #19 · Clinical › Bloodwork · 29 Nov 2025 · 16 likes No notes. Posting so the count is not one.
Half-life, steady state, and accumulation worked through — a second dataset Replied, post #23 · Pharmacology › Pharmacokinetics · 21 Nov 2025 · 0 likes Where I part company with post #19, and it is a narrow parting. Loading doses are not used in this class and the pharmacokinetic reason is tolerability rather than…
Gastro-oesophageal reflux: improving or worsening? Started this topic · Clinical › Comorbidities · 19 Nov 2025 · 0 likes The question in the title: Gastro-oesophageal reflux: improving or worsening? I will give what I have already checked below so nobody repeats it. Collecting what is…
Pharmaceutical compounding rules, summarised from primary sources — a second dataset Replied, post #33 · Sourcing › Regulatory · 16 Nov 2025 · 29 likes Everything in post #31 holds. The case it does not cover is the one I have. Practical note on Pharmaceutical compounding rules: write down what you expect before you…
Older adults, sarcopenia risk, and the trade-off nobody quantifies Replied, post #32 · Clinical › Special populations · 15 Nov 2025 · 6 likes Being outside the studied population does not mean a treatment is unsafe. It means the usual evidence is not available and the reasoning has to be explicit. Somebody…
The anatomy of a question that gets answered within an hour — the long version Replied, post #96 · Start Here › How to Ask · 14 Nov 2025 · 0 likes If the answer you got does not fit your case, say which part does not fit rather than restating the question. Otherwise the next reply is the same as the last one. The…
Where to report an adverse event officially, by region — a second dataset Replied, post #106 · Safety › Adverse events · 8 Nov 2025 · 0 likes The published trial rates come from supervised populations on defined schedules and are not comparable to rates derived from who chooses to post.
Where impurities in solid-phase peptide synthesis come from Replied, post #18 · Analytics › Impurities & related substances · 6 Nov 2025 · 15 likes The related-substances total is only as informative as the method that generated it. Two per cent by a method that resolves everything is a different statement from two…
High-resolution MS on aggregates and what it can see Replied, post #110 · Analytics › Mass spectrometry · 3 Nov 2025 · 3 likes Agreed on high-resolution, with one qualification that I think matters. The reasoning holds for the case as described. Change the starting assumption and it does not,…
Follow-up: What a seizure notice actually says Replied, post #34 · Sourcing › Logistics · 27 Oct 2025 · 3 likes I would rather this thread reach "we do not know" about seizure notice than reach a confident answer that nobody can support when asked.
What a purity-only report leaves out Replied, post #52 · Sourcing › Independent verification · 19 Oct 2025 · 0 likes Repeat determination on the same product line months apart is the measurement that speaks to consistency, and consistency is what most buyers actually want.
Coming back to: Over-dilution: when your dose falls below one readable graduation Replied, post #65 · Practice › Reconstitution · 7 Oct 2025 · 22 likes Worked example, since the arithmetic is the whole question. Five milligrams into one millilitre is 5 mg/mL. A 0.25 mg dose is 0.05 mL, which is five units on a U-100…
The most useful thing you learned here that was not the answer you came for — a second… Replied, post #69 · Lounge › Off topic · 1 Oct 2025 · 16 likes Personal stories: if you want to talk about what led you to this compound, your journey, or how the change has affected your life, the Lounge is the place for that.
Documentation that appears only after payment Replied, post #36 · Sourcing › Red flags · 29 Sep 2025 · 0 likes Answering the documentation question as asked, then the question I think is meant. As asked: yes, with the qualification below. As meant: it depends on how the first…
Coming back to: Resolution and tailing factor: real acceptance criteria Replied, post #87 · Analytics › HPLC & UHPLC · 28 Sep 2025 · 2 likes Taking post #85 at face value and following it one step further. I have been on both sides of the Resolution and tailing factor argument in this category within…
Reading a rodent study on a secretagogue without over-extrapolating Replied, post #48 · Compounds › Secretagogues & GH axis · 16 Sep 2025 · 0 likes Everything in post #46 holds. The case it does not cover is the one I have. The thing about reading a rodent study that took me longest to accept is that a plausible…
Reporting a disappointing outcome, and why it belongs here Replied, post #26 · Outcomes › Progress reports · 28 Aug 2025 · 13 likes Reading back through the reporting a disappointing outcome threads from last year, the same three questions come up every time and only one of them has ever been…
Travel coolers and how long they really hold Replied, post #47 · Devices › Cold chain · 4 Aug 2025 · 23 likes I keep a log for travel coolers specifically because my memory of it turned out to be systematically wrong in one direction. Six weeks of notes cost nothing and settled…
Coming back to: What published stability data actually covers, and what it does not Replied, post #96 · Practice › Storage & stability · 25 Jul 2025 · 0 likes I want to gently push back on the reply above about storage extrapolation. The advice is sound and the confidence is not. We are extrapolating from stability data on a…
Coming back to: When "no data" is the complete and final answer Replied, post #50 · Compounds › Other compounds · 18 Jul 2025 · 1 like I will take the caveat as seriously as the claim, which is the point of putting it there.
Coming back to: Resolution and tailing factor: real acceptance criteria Replied, post #7 · Analytics › HPLC & UHPLC · 12 Jul 2025 · 0 likes A shallow gradient resolves close-eluting species that a steep one merges. Two honest laboratories running different gradients can report genuinely different purities…
Repeatability versus intermediate precision Replied, post #58 · Analytics › Method validation · 25 Jun 2025 · 0 likes Post #54 describes the usual case. This is about the unusual one. The most useful single question about a method: what would it fail to detect? Every method has an…
Lipase elevation without symptoms: the interpretation problem — a second dataset Replied, post #15 · Clinical › Bloodwork · 15 Jun 2025 · 0 likes Where a panel includes a calculated value, that value inherits the imprecision of everything it was calculated from and is usually reported without an interval. Nothing…
Needle changes between doses on a reusable pen — does this still hold? Replied, post #5 · Devices › Pens & autoinjectors · 9 Jun 2025 · 8 likes The opening post describes the usual case. This is about the unusual one. Storage after first use: most pens can be stored at room temperature after first use, even if…
Lipase elevation without symptoms: the interpretation problem — a second dataset Replied, post #10 · Clinical › Bloodwork · 6 Jun 2025 · 4 likes The reason Lipase elevation without symptoms is hard to answer is that the obvious measurement and the relevant quantity are not the same thing, and substituting one…
Second pass at: Journal club: STEP 4 and what a withdrawal design can prove Replied, post #25 · Evidence › Journal club · 2 Jun 2025 · 20 likes Worth stating the null on STEP 4 before we explain it: the observation may be nothing. That possibility deserves a sentence and usually does not get one.
An orphaned page with no inbound links Replied, post #45 · Meta › Wiki maintenance · 26 May 2025 · 10 likes Everything in post #41 holds. The case it does not cover is the one I have. Maintainer handovers: if a page's maintainer is inactive and needs a new one, discussing…
Second pass at: Designing a personal experiment that could change your mind Replied, post #34 · Research Methods › N-of-1 designs · 21 May 2025 · 3 likes Confounding in personal experiments: other things change when you start a medication (season, exercise, diet, stress). Documenting those confounders helps you…
DXA precision and the least significant change for lean mass — the long version Replied, post #51 · Outcomes › Body composition · 16 May 2025 · 7 likes Where a facility reports a precision figure for its own machine, that number is more useful than any published average. Adding a source would improve this post and I do…
Journal club: STEP 1 and the treatment-policy estimand — does this still hold? Replied, post #74 · Evidence › Journal club · 20 Apr 2025 · 5 likes Post #73 is right about the mechanism and I think understates the practical bit. Taking STEP 1 seriously for a moment rather than deflecting: the honest position is…
Certificates issued by the seller versus by a laboratory Replied, post #35 · Analytics › COA interpretation · 7 Apr 2025 · 2 likes Where I part company with post #32, and it is a narrow parting. An itemised related-substances table with retention times says considerably more about the synthesis…
Second pass at: How to research a compound with no human data without deceiving yourself Replied, post #30 · Compounds › Other compounds · 11 Mar 2025 · 0 likes Where a compound has a legitimate pharmaceutical form somewhere in the world, the labelling for that form is usually the single most useful document available and is…
Distinguishing a deletion sequence by mass alone Replied, post #90 · Analytics › Mass spectrometry · 15 Feb 2025 · 20 likes For a compound with no reference standard in circulation, an observed mass is much more useful than an assertion of agreement with a theoretical value nobody can check.…
Revisiting: Aggregate verification data across the directory, with caveats Replied, post #2 · Sourcing › Independent verification · 5 Feb 2025 · 6 likes Repeat testing: if you want to verify the same lot a second time, testing with a different service strengthens the conclusion. Testing with the same service verifies…
Talking to a therapist about this specifically — does this still hold? Replied, post #4 · Wellbeing › Mental health · 9 Jan 2025 · 1 like Social and relationship impacts: weight change affects how others perceive and interact with a person. Those impacts are real and can be psychologically significant.…
About the Wiki requests category Replied, post #8 · Documentation › Wiki requests · 25 Dec 2024 · 4 likes Requests for a document covering something the evidence does not support get declined, and the decline usually points at what could be written instead. I would treat…
A 5 mg vial and a 0.25 mg dose: the arithmetic in full — the long version Replied, post #2 · Practice › Reconstitution · 22 Dec 2024 · 9 likes Worked example, since the arithmetic is the whole question. Five milligrams into one millilitre is 5 mg/mL. A 0.25 mg dose is 0.05 mL, which is five units on a U-100…
Building a sensible monitoring schedule with your prescriber Replied, post #39 · Clinical › Bloodwork · 20 Dec 2024 · 2 likes What would change my mind on building a sensible monitoring schedule is a second dataset collected by someone with no stake in the first. Until then I hold it loosely…
UK access routes, dated and sourced — a second dataset Replied, post #16 · Regional › UK & Ireland · 15 Dec 2024 · 3 likes Narrowing post #13, because the general version has more than one answer. Where guidance distinguishes between indications, quoting the indication is essential. The…
Domestic fridge temperature mapping: a cheap experiment — what changed since Replied, post #16 · Devices › Cold chain · 1 Dec 2024 · 14 likes Post #15 put the caveat in the right place and I want to underline it. Lyophilised material is far more tolerant of a warm transit than a solution would be, which is…
Type 1 diabetes: off-label use and the evidence gap — what changed since Replied, post #60 · Clinical › Special populations · 24 Nov 2024 · 0 likes The version of Type 1 diabetes that circulates here is a simplification of a simplification. It is not wrong, but it has lost the conditions under which it holds, and…
Why "any advice?" is the least effective ending for a post Replied, post #53 · Start Here › How to Ask · 20 Nov 2024 · 20 likes Post #52 answers the question as asked. The question underneath it is different. It is fine to say you cannot explain why you are asking. Nobody will press, and the…
Follow-up: Recovery when intake is low: what to cut first Replied, post #26 · Nutrition & Training › Resistance training · 16 Nov 2024 · 0 likes One more thing on Recovery that took me far too long to see: the two figures people quote are not measuring the same quantity. Once you notice that, the apparent…
Time to steady state after a dose increase Replied, post #54 · Pharmacology › Pharmacokinetics · 3 Nov 2024 · 0 likes Picking up post #51: that is the part I would want checked first. Metabolism for peptide drugs is proteolytic rather than hepatic in the usual sense, which is why the…
Identical chromatograms across two different lots Replied, post #28 · Sourcing › Red flags · 22 Sep 2024 · 2 likes Sensible. I would want the same detail before I acted on it either.
Progressive overload when the scale is falling — one year on Replied, post #3 · Nutrition & Training › Resistance training · 24 Aug 2024 · 0 likes Progressive overload 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.