s.ferreira

TL2 · Coimbra

Contributes reviews on supplier material. Based in Coimbra.

Joined 19 October 2024 · last posted 1d

90 posts, newest first. Showing up to 150.

Second pass at: What a 2 ppm match establishes, and what it does not Replied, post #50 · Analytics › Mass spectrometry · 27 Jul 2026 · 4 likes Post #49 is the version of this I will quote in future. One addition. Small methodological point on 2 ppm match: repeating a measurement is cheap and resolves most of…
Private prescribing in the UK: what is actually involved Replied, post #74 · Regional › UK & Ireland · 24 Jul 2026 · 12 likes Nothing in this subcategory is medical or legal advice, and prescribers reading here consistently say so themselves. I am describing what is, rather than arguing for…
Micro-titration: a disputed topic, argued properly Replied, post #106 · Practice › Dosing & titration · 17 Jul 2026 · 18 likes Answering the micro-titration 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…
Asking a follow-up: new topic or new reply? Replied, post #45 · Start Here › How to Ask · 9 Jul 2026 · 32 likes If you are asking about a document, quote the exact wording of the line you are asking about. Paraphrasing a specification is how a discussion ends up about a document…
Revisiting: The best-written scientific paper you have read Replied, post #67 · Lounge › Off topic · 3 Jul 2026 · 3 likes Industry and supply chain: post about manufacturing, pharmaceutical economics, or market dynamics if you have something substantive to contribute. If the premise is…
Designing a personal experiment that could change your mind — one year on Replied, post #64 · Research Methods › N-of-1 designs · 22 Jun 2026 · 3 likes That is a cleaner way of putting what I was circling around.
Follow-up: Comparing two chromatograms from different laboratories, properly Replied, post #43 · Analytics › HPLC & UHPLC · 15 Jun 2026 · 5 likes Area percent is a proportion of absorbance, not a proportion of mass. Two species with different extinction coefficients at the detection wavelength contribute…
Racemisation and why it is invisible to a mass measurement Replied, post #96 · Analytics › Impurities & related substances · 14 Jun 2026 · 0 likes Nobody has said the unglamorous part of racemisation yet, so: most of the variation is explained by things that are boring to write about and easy to check.
Journal club: LEADER as the historical anchor Replied, post #87 · Evidence › Journal club · 10 Jun 2026 · 8 likes Post #83 put the caveat in the right place and I want to underline it. The arithmetic on LEADER is the easy part and it is where the errors are, which is an…
I joined for one answer and stayed for a year — what changed my mind Replied, post #15 · Start Here › Welcome · 10 Jun 2026 · 18 likes One thing that took me a while to notice: the search box indexes maintained documents as well as topics, and documents carry a review date. If a document and a…
Revisiting: Journal club: SURMOUNT-OSA and a hard endpoint in a soft field Replied, post #23 · Evidence › Journal club · 8 Jun 2026 · 0 likes I read post #19 twice before replying, because I had assumed the opposite. I changed my mind about SURMOUNT-OSA after someone here asked me for the source and I could…
Follow-up: I have no scientific background — can I still follow the analytics categories? Replied, post #19 · Start Here › Welcome · 8 Jun 2026 · 0 likes The Lounge is a real category rather than a dumping ground. The sourcing rule still applies there, which surprises people, but the register is looser and nobody minds a…
Talking to a therapist about this specifically Replied, post #9 · Wellbeing › Mental health · 1 Jun 2026 · 19 likes Expectations set by other people's reported trajectories are a documented source of distress, and the trajectories posted are not representative.
Follow-up: A parcel that arrived warm: a decision process, not a verdict Replied, post #37 · Practice › Storage & stability · 22 May 2026 · 7 likes Everything in post #35 holds. The case it does not cover is the one I have. Clarity is a weak test. A solution can lose a significant fraction of its active content to…
[2026 update] 0.3 mL versus 0.5 mL versus 1 mL barrels: resolution matters Replied, post #109 · Devices › Syringes & needles · 11 May 2026 · 2 likes Trying to state the 0.3 ml versus 0.5 ml position in a way that someone who disagrees would recognise as fair, because I do not think the version in this thread passes…
A 5 mg vial and a 0.25 mg dose: the arithmetic in full Replied, post #41 · Practice › Reconstitution · 10 May 2026 · 1 like Noted, and I have changed what I was going to do on the strength of it.
Second pass at: When your prescriber and the evidence disagree Replied, post #19 · Clinical › Prescriber conversations · 8 May 2026 · 8 likes Source for the prescriber figure, since it was asked for. It is in the discussion rather than the abstract, which is why the version circulating is stronger than the…
Does a peptide degrade silently, with no visual change? Replied, post #18 · Practice › Storage & stability · 29 Apr 2026 · 0 likes Clarity is a weak test. A solution can lose a significant fraction of its active content to degradation or adsorption while remaining perfectly clear. That is one…
Reimbursement variation across member states Started this topic · Regional › European Union · 29 Apr 2026 · 41 likes Reimbursement variation across member states Writing it up because I had to work it out twice and would rather nobody else did. Asking about reimbursement variation…
Journal club: is percentage weight change the right endpoint? Replied, post #97 · Evidence › Journal club · 23 Apr 2026 · 29 likes Picking up post #94: that is the part I would want checked first. The figures usually contain the finding and the text usually contains the interpretation. Separating…
Revisiting: Body image changing more slowly than the body Replied, post #3 · Wellbeing › Mental health · 17 Apr 2026 · 0 likes Practical note on Body image: write down what you expect before you look. The number of times I have found what I went looking for is higher than chance would allow.
Second pass at: What "verified" means on our vendor pages, stated narrowly Replied, post #95 · Sourcing › Vendor reports · 16 Apr 2026 · 2 likes Adding the measurement that post #92 says would settle it. Do not adjust a reported figure. Post what the laboratory said and put your interpretation in a separate…
Citation sweep results: how many references did not say what was claimed Replied, post #76 · Meta › Wiki maintenance · 12 Apr 2026 · 21 likes Building on post #73 rather than restating it. Taking citation sweep results seriously for a moment rather than deflecting: the honest position is that the community…
List price versus negotiated price versus what you pay Replied, post #42 · Access › Pricing · 11 Apr 2026 · 0 likes I had read the opposite somewhere and cannot now find where, which tells me something.
Subgroup analyses: pre-specified versus discovered — a second dataset Replied, post #35 · Evidence › Trials · 7 Apr 2026 · 2 likes A treatment-policy estimand asks what happens to people assigned to a strategy, including those who abandon it. A hypothetical estimand asks what would have happened…
Choosing which test to pay for, given a fixed budget Replied, post #57 · Sourcing › Independent verification · 6 Apr 2026 · 5 likes Everything in post #55 holds. The case it does not cover is the one I have. Repeat determination on the same product line months apart is the measurement that speaks to…
Personal import allowances, compared — a second dataset Replied, post #85 · Access › International · 14 Mar 2026 · 0 likes I had written a reply contradicting post #81 and deleted it. Here is what survived. Licensed prescribing: where a compound is approved, prescribing is restricted to…
Revisiting: Maintainer handover: how it works Replied, post #33 · Meta › Wiki maintenance · 6 Mar 2026 · 4 likes Revision disputes: if you disagree with an edit a maintainer made, discussing it here invites resolution rather than conflict.
Grapefruit: why this class is not the class that cares Replied, post #7 · Practice › Interactions · 3 Mar 2026 · 3 likes A pharmacist can answer most questions in this subcategory in a few minutes with access to a proper interaction database, and that access is the thing a forum does not…
Managing an unplanned gap in supply Replied, post #46 · Access › Shortages · 1 Mar 2026 · 7 likes International supply chains: a shortage in one country does not mean shortage in another. That is why ordering from multiple suppliers before a shortage gets bad is…
Bioimpedance and hydration: why the number moves Replied, post #12 · Outcomes › Body composition · 27 Feb 2026 · 2 likes Reading back through, this was answered upthread and I missed it. My fault.
The 2.5 mg starting dose is not a therapeutic dose — why that matters Replied, post #18 · Compounds › Tirzepatide · 17 Feb 2026 · 30 likes Everything in post #17 holds. The case it does not cover is the one I have. Research-use-only tirzepatide is not approved for human use and is not made to…
Lean mass preservation: what the evidence supports — does this still hold? Replied, post #27 · Outcomes › Body composition · 14 Feb 2026 · 0 likes Precision versus accuracy: the precision you need depends on what question you are answering. "Am I losing fat?" requires less precision than "Is my lean mass…
Revisiting: A page that has drifted out of date and needs a maintainer Replied, post #56 · Documentation › Wiki requests · 26 Jan 2026 · 1 like On post #52 — agreed on the reasoning, with one qualification. Accessibility feedback: if you have trouble accessing or reading a maintained page (screen reader issues,…
Follow-up: Bug report: the reconstitution calculator and a rounding edge case Replied, post #24 · Data & Tools › Calculators · 16 Jan 2026 · 27 likes Reporting bugs: if you notice a calculator giving wrong results, report it in this subcategory. Bugs are fixed when identified.
Second pass at: How to ask a question when you cannot say why you are asking it Replied, post #52 · Start Here › How to Ask · 13 Jan 2026 · 17 likes On post #50 — agreed on the reasoning, with one qualification. If you are asking about a document, quote the exact wording of the line you are asking about.…
Reading an interaction checker output critically Replied, post #85 · Practice › Interactions · 6 Jan 2026 · 12 likes A note on how reading an interaction checker output gets discussed rather than on reading an interaction checker output itself: the confident posts get the replies and…
Availability by country, dated, with primary sources — one year on Replied, post #10 · Access › International · 25 Dec 2025 · 12 likes A first-hand dated account for a region with thin coverage is worth more here than any summary, and the regions with thin coverage are most of them. Happy to be the one…
Prescription requirements and telehealth models Replied, post #66 · Sourcing › Regulatory · 14 Dec 2025 · 21 likes Summarising the prescription requirements and telehealth models thread so far, since it is long and the answer is buried: the first reply has the method, the fourth has…
Tracking a preprint to publication: a worked example Replied, post #135 · Evidence › Preprints · 13 Dec 2025 · 4 likes No notes. Posting so the count is not one.
Filter needles: when they help and what they cost you Replied, post #2 · Devices › Syringes & needles · 8 Dec 2025 · 3 likes Sharps disposal: needles and syringes should be disposed in a sharps container (a rigid, puncture-resistant container). Do not put them in regular trash. Many…
LOD and LOQ: definitions people get wrong Replied, post #2 · Analytics › Method validation · 18 Nov 2025 · 0 likes Precision has two levels worth distinguishing: repeatability within a run and intermediate precision across days, analysts and instruments. The second is where most…
The headache that turns out to be dehydration Replied, post #60 · Nutrition & Training › Hydration & electrolytes · 17 Nov 2025 · 8 likes That is consistent with mine, for whatever one more account is worth.
Where to report an adverse event officially, by region — a second dataset Replied, post #123 · Safety › Adverse events · 12 Nov 2025 · 10 likes Everything in post #121 holds. The case it does not cover is the one I have. Nothing here is medical advice, and in this subcategory the phrase is doing more work than…
A parcel that arrived warm: a decision process, not a verdict Replied, post #114 · Practice › Storage & stability · 1 Nov 2025 · 15 likes Visible particulate is a strong signal in the other direction: it is a reason to stop and ask rather than to filter and proceed. None of the above is medical advice and…
Tracking that stops updating and then resumes Replied, post #35 · Sourcing › Logistics · 12 Oct 2025 · 0 likes Post #33 and I disagree about the size of the effect, not about the direction. Peak periods and public holidays affect this more than any other factor and are entirely…
Comparing my trajectory with the trial curves, carefully Replied, post #55 · Outcomes › Progress reports · 29 Sep 2025 · 0 likes Self-reported intake is optimistic in a consistent direction, and saying so in your own report is more credible than not.
A checklist for reading a certificate in under two minutes — does this still hold? Replied, post #49 · Analytics › COA interpretation · 26 Sep 2025 · 0 likes Narrowing post #48, because the general version has more than one answer. An itemised related-substances table with retention times says considerably more about the…
Power cut for eleven hours: how I assessed it afterwards Replied, post #67 · Practice › Storage & stability · 22 Sep 2025 · 0 likes Visible particulate is a strong signal in the other direction: it is a reason to stop and ask rather than to filter and proceed. That distinction has done more work for…
Severe abdominal pain: why this is not a forum question — one year on Replied, post #2 · Safety › Adverse events · 18 Sep 2025 · 6 likes Allergic reactions: true allergy (anaphylaxis, severe rash) is rare with these peptide compounds but possible. Distinguishing true allergy from GI intolerance matters.
Reverse causation in a cohort study of weight and outcome — a second dataset Replied, post #122 · Evidence › Study critique · 16 Sep 2025 · 0 likes Hold a trial to the standard something could actually have met. A criticism that no achievable design could have answered is a criticism of the field rather than of the…
Asking about a compound your prescriber has not heard of Replied, post #135 · Clinical › Prescriber conversations · 23 Aug 2025 · 30 likes Everything in post #131 holds. The case it does not cover is the one I have. A question phrased as "what would you want to see before considering X" is answerable and…
Angle of injection and whether 90 degrees is always right Replied, post #7 · Practice › Administration · 4 Aug 2025 · 19 likes Bleeding at the injection site: normal and usually minimal. A little blood at the needle site after withdrawal is not a reason to assume you lost a significant dose.…
Coming back to: Lurking for two months before posting: was that the right call? Replied, post #21 · Start Here › Welcome · 3 Aug 2025 · 0 likes Reading the guidelines before you post is genuinely worth the twenty minutes. Not because you will break one, but because the rules explain why the place reads the way…
How to research a compound with no human data without deceiving yourself Replied, post #34 · Compounds › Other compounds · 31 Jul 2025 · 2 likes Research a compound has been discussed here with more heat than it deserves, mostly because two definitions have been in play the whole time.
Coming back to: Semaglutide half-life: where the 165 to 184 hour figure comes from Replied, post #85 · Compounds › Semaglutide · 24 Jul 2025 · 0 likes Post #83 describes the usual case. This is about the unusual one. Gallbladder events appear in the labelling for this class and are more common with larger, faster…
Asking about a compound your prescriber has not heard of Replied, post #100 · Clinical › Prescriber conversations · 20 Jul 2025 · 0 likes Post #96 put the caveat in the right place and I want to underline it. Bringing a record of symptoms with dates and severities makes an assessment materially easier and…
Coming back to: Why semaglutide solutions can look faintly opalescent and when that… Replied, post #2 · Compounds › Semaglutide · 20 Jun 2025 · 8 likes The opening post put the caveat in the right place and I want to underline it. Semaglutide versus liraglutide in STEP 8: semaglutide produced greater weight reduction…
Why plausible mechanism is not evidence of effect Replied, post #14 · Compounds › Repair & healing peptides · 7 Jun 2025 · 19 likes Picking up post #11: that is the part I would want checked first. Oral versus injected administration claims for BPC-157: the preclinical work studied injection. Oral…
Pre-registering a personal experiment, seriously Replied, post #32 · Research Methods › N-of-1 designs · 28 May 2025 · 20 likes That reframing is the whole thing. The facts I already had.
Triple agonism: additive, synergistic, or neither? Replied, post #41 · Compounds › Retatrutide · 30 Apr 2025 · 1 like Where I part company with post #38, and it is a narrow parting. A request rather than an answer: could whoever has the primary source for triple agonism post it? I have…
Requesting a page: what makes a good request Replied, post #66 · Documentation › Wiki requests · 22 Apr 2025 · 0 likes I came in to disagree and I am leaving without a disagreement.
Journal club: STEP 1 and the treatment-policy estimand — does this still hold? Replied, post #24 · Evidence › Journal club · 18 Apr 2025 · 12 likes Grateful for the specificity. Vague answers to this question are what sent me looking.
About the Secretagogues & GH axis category Replied, post #6 · Compounds › Secretagogues & GH axis · 13 Apr 2025 · 20 likes That is consistent with mine, for whatever one more account is worth.
Sequence verification for an obscure compound: how it is done Replied, post #11 · Compounds › Other compounds · 12 Apr 2025 · 18 likes The version of sequence verification that circulates here is a simplification of a simplification. It is not wrong, but it has lost the conditions under which it holds,…
A supplier that answers analytical questions with restated claims Replied, post #53 · Sourcing › Red flags · 7 Apr 2025 · 12 likes Claims of pharmaceutical-grade status for research-use-only material are a labelling problem and are common enough to be worth expecting rather than reacting to. The…
Carryover and the ghost peak from last week's standard Replied, post #49 · Analytics › HPLC & UHPLC · 7 Apr 2025 · 0 likes I came in to disagree and I am leaving without a disagreement.
A certificate with no method stated: what can you conclude? Replied, post #18 · Analytics › COA interpretation · 2 Apr 2025 · 0 likes Worth separating two things that post #16 runs together. A chromatogram supplied as a small image is legible for peak shape and not for baseline detail. That is enough…
Second pass at: Gauge and length selection for subcutaneous injection Replied, post #49 · Devices › Syringes & needles · 2 Apr 2025 · 0 likes Sharps containers are a legal requirement for disposal in several jurisdictions and a sensible precaution everywhere. A rigid sealed container is the minimum. That is…
Revisiting: Completing a dose with a second syringe, and the dead-volume arithmetic Replied, post #9 · Practice › Administration · 30 Mar 2025 · 0 likes Completing a dose: I would want to see the raw numbers rather than the summary before agreeing. Summaries lose exactly the information that would settle this.
Coverage for the indication versus for the drug — a second dataset Replied, post #50 · Access › Insurance & coverage · 29 Mar 2025 · 12 likes I think the Coverage question is answerable and has not been answered, which is a more optimistic position than most of this thread.
Coming back to: GHRH analogues versus ghrelin mimetics: different mechanisms, conflated… Replied, post #14 · Compounds › Secretagogues & GH axis · 12 Mar 2025 · 8 likes CJC-1295 exists in two forms in circulation — with and without the drug affinity complex — and they have very different half-lives. Product descriptions frequently do…
Review: a draft on reconstitution arithmetic, with objections Replied, post #22 · Documentation › Doc review · 14 Feb 2025 · 1 like Confirming post #21 from a second method, which matters more than confirming it from a second person. On draft on reconstitution arithmetic I would separate what is…
Second pass at: Cross-border purchase within the EU: the actual rules Replied, post #43 · Access › International · 14 Feb 2025 · 32 likes Adding the measurement that post #40 says would settle it. What would change my mind on Cross-border purchase within is a second dataset collected by someone with no…
Revisiting: Heart failure with preserved ejection fraction: symptom endpoints Replied, post #6 · Clinical › Comorbidities · 26 Jan 2025 · 4 likes If someone has run Heart failure with preserved ejection properly I would rather read that than my own reconstruction of it. Posting mine only because the thread has…
Research-use-only labelling: what it means and what it does not — the long version Replied, post #54 · Sourcing › Regulatory · 30 Dec 2024 · 0 likes The thing about Research-use-only labelling that took me longest to accept is that a plausible mechanism is not evidence of an effect. It is a reason to look, not a…
Why pulsatile secretion matters for interpreting secretagogue claims — a second dataset Replied, post #32 · Compounds › Secretagogues & GH axis · 29 Dec 2024 · 7 likes The reason pulsatile secretion 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…
Converting between mg/mL and units per dose, both directions Replied, post #124 · Practice › Reconstitution · 10 Dec 2024 · 10 likes Post #123 is the version of this I will quote in future. One addition. Reconstituting a multi-strength kit: if a kit contains 5 mg, 10 mg, 15 mg vials and you are…
[2026 update] New subcategory: rationale and scope Replied, post #37 · Meta › Announcements · 2 Dec 2024 · 2 likes I keep a log for New subcategory specifically because my memory of it turned out to be systematically wrong in one direction. Six weeks of notes cost nothing and…
Athletes in weight-category sports: a different risk calculus — a second dataset Replied, post #27 · Clinical › Special populations · 25 Nov 2024 · 18 likes Two claims get bundled together under Athletes in weight-category sports and they need separating. The descriptive one — this is what was observed — is usually well…
Washout with a one-week half-life: the arithmetic Replied, post #5 · Research Methods › N-of-1 designs · 22 Nov 2024 · 20 likes Coming back to post #3, because the follow-up matters more than the original answer. The reason washout keeps being re-asked is that the answer is conditional and…
Revisiting: Moderation log format change Replied, post #19 · Meta › Announcements · 7 Nov 2024 · 0 likes Adding the measurement that post #18 says would settle it. Thank you for announcing it in advance rather than after. The number of places that do the reverse is…
Second pass at: A field-by-field walk through a certificate of analysis Replied, post #91 · Analytics › COA interpretation · 21 Oct 2024 · 19 likes Where two documents for the same lot disagree, the useful question is which was measured and which was transcribed. Most such disagreements are the second. A modest…
What a stability-indicating method is and how you demonstrate one — one year on Replied, post #52 · Analytics › Method validation · 15 Oct 2024 · 8 likes Accuracy: the method measures what you intend to measure. For purity methods, this is tested by spike-and-recover experiments: add a known amount of impurity to a…
Why we hide unevidenced fraud accusations and log the hiding Replied, post #6 · Sourcing › Red flags · 15 Oct 2024 · 2 likes The strongest single signal available cheaply is what happens when you ask a technical question. A quantitative answer inside a working day is difficult to fake at…
Progressive overload when the scale is falling — one year on Replied, post #150 · Nutrition & Training › Resistance training · 12 Oct 2024 · 16 likes Worth separating two things that post #146 runs together. The reports here that state the programme, the load and the timeframe are useful. The ones that state an…
US compounding rules and how they changed Replied, post #15 · Regional › North America · 7 Oct 2024 · 22 likes Post #12 answers the question as asked. The question underneath it is different. Date every claim in this subcategory. Positions here have moved repeatedly and old…
How to ask for a dose change without antagonising anyone Replied, post #15 · Clinical › Prescriber conversations · 16 Aug 2024 · 0 likes Bringing a record of symptoms with dates and severities makes an assessment materially easier and is the single most useful preparation.
Promotion criteria, and the one that stops most nominations Replied, post #39 · Documentation › Doc review · 16 Aug 2024 · 6 likes Check the links. Promotion frequently breaks a cross-reference because the source topic now points at the document rather than the reverse.
Why I ask for the gradient before I discuss the number Replied, post #2 · Analytics › HPLC & UHPLC · 14 Jun 2024 · 1 like Area percent is not mass percent. It is a proportion of absorbance, weighted by each species' extinction coefficient. For closely related impurities the approximation…