b.wikstrom

TL2 · Porto

Contributes reviews on supplier material. Based in Porto.

Joined 29 July 2025 · last posted 8d

82 posts, newest first. Showing up to 150.

Here for the analytics and not much else Replied, post #60 · Lounge › Introductions · 20 Jul 2026 · 0 likes 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…
Coming back to: Specificity, linearity, accuracy, precision, range, robustness — with… Replied, post #95 · Analytics › Method validation · 18 Jul 2026 · 0 likes Practical note on Specificity: 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.
[2026 update] Interpreting a result that disagrees with the supplier's certificate Replied, post #81 · Sourcing › Independent verification · 11 Jul 2026 · 13 likes Building on post #78 rather than restating it. The record shows what was measured. Everything beyond that is inference and this site tries to keep the line visible.…
Alcohol: what is documented and what is folklore Replied, post #79 · Practice › Interactions · 27 Jun 2026 · 1 like Anything that also slows gut motility compounds the same mechanism. That is a plausibility argument rather than a documented interaction, and it should be labelled as…
About the Welcome category Replied, post #4 · Start Here › Welcome · 25 Jun 2026 · 1 like Suggestion for the wiki post above: it would be worth linking the two or three most-referenced topics in this category directly, since new members reliably ask for…
Batch numbers that do not match the vial label Replied, post #33 · Sourcing › Red flags · 23 Jun 2026 · 1 like Adding a null result on batch numbers. I looked, carefully, and found nothing, and null results deserve posting precisely because they never are.
Run-in periods and the population they select Replied, post #135 · Evidence › Trials · 12 Jun 2026 · 14 likes Population narrowness: most trials in this class enrolled fairly specific groups. Baseline body mass index ranges, exclusion of renal disease, exclusion of certain…
What I would want from a home test that does not exist yet — what changed since Replied, post #47 · Analytics › Home & field testing · 8 Jun 2026 · 0 likes Why third-party testing is stronger: a home test run by the person who made the compound is a self-selected result. The test run by a neutral third party removes…
Comparing prices across jurisdictions without misleading yourself Replied, post #51 · Access › Pricing · 7 Jun 2026 · 0 likes Narrowing post #48, because the general version has more than one answer. Worth stating the null on comparing prices across jurisdictions before we explain it: the…
Spreadsheets: an appreciation — what changed since Replied, post #63 · Lounge › Off topic · 6 Jun 2026 · 4 likes Second this, and I would have said it less carefully.
Second pass at: A pooled estimate that changed when one trial was added Replied, post #9 · Evidence › Meta-analyses · 20 May 2026 · 10 likes Double extraction with disagreement resolution is standard and is worth checking for, because single extraction errors are common and non-random. One of those cases…
Second pass at: Metformin co-administration and additive GI effects Replied, post #107 · Practice › Interactions · 18 May 2026 · 5 likes Everything in post #103 holds. The case it does not cover is the one I have. SGLT2 inhibitors: frequently co-administered and relevant to renal and cardiovascular…
Second pass at: What a 2 ppm match establishes, and what it does not Replied, post #12 · Analytics › Mass spectrometry · 10 May 2026 · 2 likes I read post #11 twice before replying, because I had assumed the opposite. Positional isomers and epimers are mass-identical. Any argument that a mass result rules them…
Measurement error in home scales, with a worked standard deviation — the long version Replied, post #97 · Research Methods › Statistics · 6 May 2026 · 2 likes If someone has run Measurement error in home scales properly I would rather read that than my own reconstruction of it. Posting mine only because the thread has gone…
Why the titration planner refuses to produce a schedule below a floor Replied, post #64 · Data & Tools › Calculators · 21 Apr 2026 · 17 likes A saved calculation is worth more than a remembered one. Write down the inputs alongside the result, because the result alone is unverifiable a month later. A single…
An 18-month record including the parts that went badly Replied, post #2 · Outcomes › Progress reports · 20 Apr 2026 · 5 likes I would call the community position on 18-month record likely rather than established, and I would be comfortable defending that hedge.
A parcel stationary at a customs facility for nine days — does this still hold? Replied, post #14 · Sourcing › Logistics · 10 Apr 2026 · 0 likes Reframing parcel stationary slightly, because I think the disagreement is about the question rather than the answer. If the question is "does it happen", yes. If it is…
Type 2 diabetes and the largest part of the evidence base Replied, post #48 · Clinical › Comorbidities · 30 Mar 2026 · 10 likes What I would check first on type 2 diabetes is whether the thing being measured moved or whether the way of measuring it moved. Those look identical in a graph.
Journal club: is percentage weight change the right endpoint? Replied, post #8 · marked as the solution · Evidence › Journal club · 22 Mar 2026 · 25 likes The figures usually contain the finding and the text usually contains the interpretation. Separating them for the first twenty minutes is a discipline worth keeping.…
Spreadsheets: an appreciation — what changed since Replied, post #4 · Lounge › Off topic · 21 Mar 2026 · 25 likes Spreadsheets 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.
Why chargeback is not the safety net people assume Replied, post #5 · Sourcing › Payments · 18 Mar 2026 · 16 likes Building on post #2 rather than restating it. Order confirmations that state the lot to be shipped are rare and are the single most useful thing a supplier can put on…
Request: export my own posts — one year on Replied, post #59 · Meta › Feature requests · 15 Mar 2026 · 0 likes That would be genuinely useful in the vendor pages too, where a discussion link often means posts eleven through fifteen and points at eleven.
[2026 update] What a purity-only report leaves out Replied, post #48 · Sourcing › Independent verification · 9 Mar 2026 · 8 likes This follows post #45 rather than contradicting it. Source for the purity-only figure, since it was asked for. It is in the discussion rather than the abstract, which…
Angle of injection and whether 90 degrees is always right Replied, post #110 · Practice › Administration · 3 Mar 2026 · 32 likes Drawing up with one needle and injecting with another: a reasonable practice if you have extra needles. Fresh needle for injection reduces tissue drag and can decrease…
Revisiting: Liver enzymes drifting down and what that usually means Replied, post #6 · Clinical › Bloodwork · 21 Feb 2026 · 32 likes Worth separating two things that post #5 runs together. What I can speak to on Liver enzymes drifting is narrow, so I will keep it narrow rather than generalising from…
Why "dose equivalence" between different incretin analogues is a weak concept Replied, post #88 · Practice › Dosing & titration · 19 Feb 2026 · 20 likes Acknowledging rather than arguing. The reasoning holds as far as I can follow it.
Liver enzymes drifting down and what that usually means Replied, post #57 · Clinical › Bloodwork · 16 Feb 2026 · 12 likes Post #56 is the version of this I will quote in future. One addition. Reference intervals: constructed to contain the central 95% of a reference population, which means…
What I would record differently if I started again — the long version Replied, post #27 · Outcomes › Progress reports · 13 Feb 2026 · 0 likes Non-scale victories: muscle gain or maintenance, clothing fit, energy level, and capability (like climbing stairs without breathlessness) are measurements that…
Reconstitution volumes that produce round numbers, tabulated Replied, post #44 · Practice › Reconstitution · 12 Feb 2026 · 8 likes Reading back through the reconstitution volumes threads from last year, the same three questions come up every time and only one of them has ever been answered…
Interpreting a result that disagrees with the supplier's certificate Replied, post #112 · Sourcing › Independent verification · 7 Feb 2026 · 0 likes Post #109 is the version of this I will quote in future. One addition. Second-hand on interpreting a result, so weight it accordingly — someone whose method I trust…
[2026 update] Confounding by indication, explained with a concrete example Replied, post #26 · Evidence › Study critique · 4 Feb 2026 · 0 likes Multiple comparisons: if a paper reports many outcomes, the chance of a spurious association by random chance is real. Pre-specification of primary outcomes matters and…
Comparing my trajectory with the trial curves, carefully — a second dataset Replied, post #5 · Outcomes › Progress reports · 1 Feb 2026 · 18 likes Where I part company with post #3, and it is a narrow parting. Self-reported intake is optimistic in a consistent direction, and saying so in your own report is more…
A partial dose because the pen emptied mid-injection Replied, post #85 · Practice › Administration · 10 Jan 2026 · 24 likes Whatever the answer on partial dose because the pen turns out to be, the method for getting there is the same: state the assumption, do the arithmetic in public, invite…
A widely repeated interaction claim that turns out to be unsupported Replied, post #14 · Practice › Interactions · 25 Dec 2025 · 0 likes The most defensible general position in this subcategory: identify the plausible mechanism, check whether it has been studied, and where it has not, say that rather…
Common supplements people ask about, assessed one at a time — a second dataset Replied, post #22 · Practice › Interactions · 18 Dec 2025 · 7 likes I had written a reply contradicting post #20 and deleted it. Here is what survived. I have three months of notes on Common supplements and the honest summary is that…
Interpreting a result that disagrees with the supplier's certificate Replied, post #47 · Sourcing › Independent verification · 18 Dec 2025 · 24 likes I read post #43 twice before replying, because I had assumed the opposite. Verification records are dated because they expire in usefulness. A result from two years ago…
The decimal-point error, and the habit that catches it Replied, post #67 · Practice › Reconstitution · 16 Dec 2025 · 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…
Dead volume across syringe and needle combinations Replied, post #36 · Devices › Syringes & needles · 10 Dec 2025 · 16 likes This follows post #33 rather than contradicting it. Safety-engineered needles are worth using if you have children or anyone else in the house, and the retraction…
Stepping down deliberately, and how to do it without losing progress Replied, post #18 · Practice › Dosing & titration · 23 Nov 2025 · 5 likes I had written a reply contradicting post #14 and deleted it. Here is what survived. A titration plan written down in advance is easier to stick to and easier to abandon…
Promotion criteria, and the one that stops most nominations — the long version Replied, post #90 · Documentation › Doc review · 9 Nov 2025 · 0 likes The four criteria are that the question recurs, that the content is correct and sourced or labelled as community practice, that somebody will be named as maintainer…
[2026 update] What steady state means for the decision to escalate Replied, post #30 · Practice › Dosing & titration · 7 Nov 2025 · 3 likes This is the answer, and the reason it is the answer is the more useful part.
Temperature loggers worth the money — the long version Replied, post #64 · Devices › Cold chain · 28 Oct 2025 · 8 likes Worth separating Temperature loggers worth the money as a question about the compound from Temperature loggers worth the money as a question about the documentation.…
Payment mechanics and the recovery options that do not exist Replied, post #36 · Sourcing › Payments · 20 Oct 2025 · 8 likes Recording the time from payment to dispatch is worth doing, because it is the part of the process most within the supplier's control. It cost nothing to check and would…
Payment mechanics and the recovery options that do not exist Replied, post #9 · Sourcing › Payments · 18 Oct 2025 · 0 likes Fraud and scams: if a supplier demands payment upfront with no recourse if delivery fails, you are taking a risk. Reputation and history of other buyers matter. One of…
Retatrutide's phase 2 heart-rate signal and how to think about it Replied, post #7 · Compounds › Retatrutide · 12 Oct 2025 · 25 likes Duration is the other limitation. The published exposure is measured in months, and the questions people are actually asking are about years. The strength of my opinion…
Compounds this community declines to help with, and why Replied, post #62 · Compounds › Other compounds · 4 Oct 2025 · 1 like 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…
Second pass at: The mass-error checker and its intended scope Replied, post #21 · Data & Tools › Calculators · 20 Sep 2025 · 0 likes Adding the measurement that post #18 says would settle it. Significant figures in the output should not exceed what the inputs support. A concentration calculated from…
The most useful thing you learned here that was not the answer you came for — a second… Replied, post #37 · Lounge › Off topic · 15 Sep 2025 · 0 likes Clear enough that I do not think I have a follow-up, which is unusual.
Detection wavelength and why 214 nm and 280 nm disagree Replied, post #46 · Analytics › HPLC & UHPLC · 10 Sep 2025 · 5 likes Where I would push back on the detection wavelength consensus is the confidence, not the direction. The direction looks right. The confidence is borrowed.
[2026 update] Hello from a laboratory that does not do peptides Started this topic · Lounge › Introductions · 26 Aug 2025 · 1 like Hello from a laboratory that does not do peptides Writing it up because I had to work it out twice and would rather nobody else did. Saying hello, and stating my…
Pinch or no pinch, and how needle length changes the answer Replied, post #26 · Practice › Administration · 20 Aug 2025 · 19 likes Offering a way to settle pinch rather than another opinion about it. Two measurements, taken the same way, a fortnight apart. If the difference is within the noise, the…
Coming back to: Sample size calculations, read backwards from the published number Replied, post #75 · Evidence › Trials · 17 Aug 2025 · 32 likes I read post #73 twice before replying, because I had assumed the opposite. Having read the whole Sample size calculations thread before replying: the question in the…
What the GIP component of tirzepatide is thought to contribute, and how confident we can… Replied, post #27 · Compounds › Tirzepatide · 16 Aug 2025 · 13 likes Confirming post #24 from a second method, which matters more than confirming it from a second person. Nausea profile: some people report tirzepatide as less…
A field-by-field walk through a certificate of analysis Replied, post #46 · Analytics › COA interpretation · 15 Jul 2025 · 17 likes Post #42 put the caveat in the right place and I want to underline it. What fields matter on a certificate: lot number matching the vial, test date, the analytical…
Reading a regulatory notice rather than an article about it — what changed since Replied, post #19 · Sourcing › Regulatory · 13 Jun 2025 · 0 likes The arithmetic in post #16 is right; the assumption feeding it is the part to check. Regulatory approval is a decision about a specific product from a specific…
Coming back to: Semaglutide half-life: where the 165 to 184 hour figure comes from Replied, post #25 · Compounds › Semaglutide · 12 Jun 2025 · 32 likes Post #21 and I disagree about the size of the effect, not about the direction. If you are new and reading this thread for the answer to Semaglutide half-life: the…
The CagriSema phase 2 paper and what a fixed combination buys — the long version Replied, post #24 · Compounds › Cagrilintide & amylin analogues · 6 Jun 2025 · 14 likes Two questions I would want answered before drawing anything from the CagriSema phase 2 paper data above: how were the cases selected, and what happened to the ones that…
[2026 update] Citation sweep results: how many references did not say what was claimed Replied, post #34 · Meta › Wiki maintenance · 5 Jun 2025 · 0 likes Careful with that. A short duplicated paragraph is sometimes better than a link, because the reader who needs it is mid-task and will not follow a link. The test is…
Journal club: STEP 4 and what a withdrawal design can prove Replied, post #50 · Evidence › Journal club · 3 Jun 2025 · 25 likes Coming back to post #48, because the follow-up matters more than the original answer. The reason STEP 4 keeps being re-asked is that the answer is conditional and…
Detection wavelength and why 214 nm and 280 nm disagree Started this topic · Analytics › HPLC & UHPLC · 22 May 2025 · 23 likes On the subject in the title: Detection wavelength and why 214 nm and 280 nm disagree Working notes rather than a conclusion. I would like to disagree carefully with the…
Why quantitation is the hard part, not detection Replied, post #9 · Analytics › Home & field testing · 12 Apr 2025 · 15 likes Ultraviolet absorbance at 280 nanometres estimates concentration for peptides containing aromatic residues and gives nothing for peptides that do not. Knowing which…
Review: a draft on reconstitution arithmetic, with objections Replied, post #80 · Documentation › Doc review · 29 Mar 2025 · 9 likes Ask what the page would look like if it were wrong. A document with no stated failure conditions is hard to review and harder to maintain.
Adjudicated events and why the definition matters — the long version Replied, post #67 · Evidence › Trials · 27 Mar 2025 · 5 likes Taking Adjudicated events seriously for a moment rather than deflecting: the honest position is that the community has observations and no controlled comparison, and…
Why cagrilintide alone is discussed so much less than in combination Replied, post #27 · Compounds › Cagrilintide & amylin analogues · 25 Mar 2025 · 10 likes That matches what I have seen, for whatever a single anecdote is worth.
Journal club: SURMOUNT-OSA and a hard endpoint in a soft field Replied, post #26 · Evidence › Journal club · 6 Mar 2025 · 0 likes On post #24 — agreed on the reasoning, with one qualification. The thing about SURMOUNT-OSA that took me longest to accept is that a plausible mechanism is not evidence…
Charge states for a 4 kDa peptide, worked through Replied, post #4 · Analytics › Mass spectrometry · 1 Mar 2025 · 0 likes Desalting before analysis: some samples need desalting to remove salts that suppress the peptide signal. Report whether desalting was used, because it can affect the…
Pharmaceutical compounding rules, summarised from primary sources Replied, post #8 · Sourcing › Regulatory · 27 Feb 2025 · 28 likes One more thing on pharmaceutical compounding rules that took me far too long to see: the two figures people quote are not measuring the same quantity. Once you notice…
Research-use-only labelling: what it means and what it does not — the long version Replied, post #88 · Sourcing › Regulatory · 19 Feb 2025 · 1 like If you can confirm or contradict a position for your own region, please date the answer. An undated regional claim is the least useful thing in this category. If the…
Coming back to: Recording a dissent on a document rather than suppressing it Replied, post #20 · Documentation › Doc review · 31 Dec 2024 · 0 likes Where content is lifted from a topic, attribution should be in the document rather than only in the review thread. The answer changed when I changed how I was…
Fixed versus detachable needles: the trade-offs Replied, post #66 · Devices › Syringes & needles · 23 Dec 2024 · 20 likes This settles it for me, at least until somebody posts a reason it should not.
Follow-up: Tirzepatide's shorter half-life and its one practical consequence Replied, post #60 · Compounds › Tirzepatide · 29 Nov 2024 · 19 likes Heart rate rises modestly across this class, tirzepatide included. It is consistent, small, and worth knowing about rather than worth alarm — and it is one of the…
Meeting a protein target on a suppressed appetite — does this still hold? Replied, post #16 · Nutrition & Training › Protein & intake · 22 Nov 2024 · 13 likes Taking post #15 at face value and following it one step further. Micronutrition alongside protein: eating protein foods that are also good sources of micronutrients…
Choosing which test to pay for, given a fixed budget — does this still hold? Replied, post #39 · Sourcing › Independent verification · 20 Nov 2024 · 15 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…
Follow-up: Where the four-week escalation interval comes from, and what it is not Replied, post #85 · Practice › Dosing & titration · 17 Oct 2024 · 6 likes I came in to disagree and I am leaving without a disagreement.
Coming back to: The nausea timeline across the first four weeks, with a tabulated log Replied, post #14 · Practice › Side effects · 15 Sep 2024 · 10 likes Nausea timeline is well covered in the tag pages, and the older discussions are better than the recent ones because they were argued out properly. Worth twenty minutes…
Why pulsatile secretion matters for interpreting secretagogue claims — a second dataset Replied, post #8 · Compounds › Secretagogues & GH axis · 2 Sep 2024 · 16 likes Reading a rodent study on a secretagogue without over-extrapolating: rodent studies can show a mechanism is plausible. They cannot show magnitude of effect in humans or…
SURPASS-2 and the comparator dose question that will not go away Replied, post #9 · Compounds › Tirzepatide · 2 Sep 2024 · 0 likes This is the first time the answer has come with its own limits attached. Appreciated.
Follow-up: Dead volume across syringe and needle combinations Replied, post #26 · Devices › Syringes & needles · 26 Aug 2024 · 1 like Picking up post #23: that is the part I would want checked first. One more thing on Dead volume across syringe that took me far too long to see: the two figures people…
Second pass at: Retatrutide dose escalation in the published trials Replied, post #95 · Compounds › Retatrutide · 22 Jul 2024 · 8 likes Taking post #92 at face value and following it one step further. Comparisons with tirzepatide are being made across trials rather than within one. Different…
Oral contraceptives and delayed emptying: what the data shows Replied, post #61 · Practice › Interactions · 17 Jul 2024 · 6 likes Building on post #58 rather than restating it. Oral medications with a narrow therapeutic index are the ones where that matters most. The interaction is about rate and…
Cold packs, phase-change material, and what survives ten days Replied, post #82 · Sourcing › Logistics · 8 Jul 2024 · 32 likes Delivery to an address where somebody is present is worth more for cold-chain material than any packing decision available to the supplier.
Assessing a warm arrival: the decision process — one year on Replied, post #46 · Sourcing › Logistics · 30 May 2024 · 8 likes Documentation after arrival: photograph the parcel and its contents on arrival. If something later turns out wrong (damage, loss, wrong item) you have evidence of the…