l.ferreira

TL2 · Uppsala

Contributes reviews on supplier material. Based in Uppsala.

Joined 25 August 2025 · last posted 3d

83 posts, newest first. Showing up to 150.

Which categories are strict and which are relaxed, honestly Replied, post #50 · Start Here › Welcome · 25 Jul 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…
Does a peptide degrade silently, with no visual change? Replied, post #77 · Practice › Storage & stability · 23 Jul 2026 · 0 likes Freezing a reconstituted peptide solution is not automatically protective. Freeze-thaw cycling is one of the harsher things you can do to a protein in solution, and a…
Why a glucagon receptor agonist in a weight-loss compound is not a contradiction Replied, post #43 · Compounds › Retatrutide · 22 Jul 2026 · 0 likes Post #41 describes the usual case. This is about the unusual one. Glycaemic effects improved rather than worsened in the diabetes work despite the glucagon component,…
I joined for one answer and stayed for a year — what changed my mind Replied, post #93 · Start Here › Welcome · 19 Jul 2026 · 3 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…
Seven-day rolling means and why weekly readings mislead Replied, post #23 · Outcomes › Progress reports · 13 Jul 2026 · 0 likes Noted, and I have changed what I was going to do on the strength of it.
I joined for one answer and stayed for a year — what changed my mind Replied, post #72 · Start Here › Welcome · 10 Jul 2026 · 26 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…
Review: a draft on reconstitution arithmetic, with objections — what changed since Replied, post #37 · Documentation › Doc review · 7 Jul 2026 · 0 likes Post #35 and I disagree about the size of the effect, not about the direction. Adding the boring version of draft on reconstitution arithmetic, because the interesting…
Why this subcategory is stricter about sourcing than most Replied, post #51 · Compounds › Secretagogues & GH axis · 3 Jul 2026 · 12 likes Reading back through, this was answered upthread and I missed it. My fault.
Second pass at: Sleep apnoea improving and the equipment implications Replied, post #72 · Wellbeing › Sleep · 30 Jun 2026 · 26 likes A referral for a proper sleep study answers in one night what months of forum discussion cannot. It cost nothing to check and would have cost something not to.
What to include when your question involves a chromatogram — one year on Replied, post #55 · Start Here › How to Ask · 28 Jun 2026 · 22 likes On post #52 — agreed on the reasoning, with one qualification. Avoid "any advice?" at the end. It is so generic that people do not know which part of the post it refers…
Aggregate verification data across the directory, with caveats Replied, post #7 · Sourcing › Independent verification · 21 Jun 2026 · 0 likes The lot identifier has to match across vial, certificate and invoice for any of this to mean anything. It is the floor and it is worth checking every time. Two sources,…
Blinding yourself: practical methods and their limits Replied, post #35 · Research Methods › N-of-1 designs · 18 Jun 2026 · 4 likes I had written a reply contradicting post #33 and deleted it. Here is what survived. Committing to post the result before you know it is a useful precommitment, and this…
What would change my mind about repair peptides: a specific answer Replied, post #10 · Compounds › Repair & healing peptides · 14 Jun 2026 · 1 like Post #6 and I disagree about the size of the effect, not about the direction. Dose-response is unstudied in humans for essentially everything in this family, which…
What to include when your question involves a laboratory result Replied, post #8 · Start Here › How to Ask · 14 Jun 2026 · 11 likes No disagreement from me. Posting only so the question does not look ignored.
Coming back to: Solubility limits and what a cloudy solution is telling you Replied, post #29 · Pharmacology › Formulation chemistry · 6 Jun 2026 · 0 likes Benzyl alcohol as a preservative is also a solubiliser for some peptides, which is an incidental property that occasionally matters.
Why the timeline is on the right and not the left — what changed since Replied, post #47 · Meta › Site feedback · 2 Jun 2026 · 12 likes Coming back to post #43, because the follow-up matters more than the original answer. Last piece of feedback: the site is much better on a narrow screen than it was six…
Alcohol: what is documented and what is folklore Replied, post #30 · Practice › Interactions · 27 May 2026 · 23 likes Post #29 put the caveat in the right place and I want to underline it. Something worth flagging about alcohol: the strongest-sounding claims in this thread are the ones…
Follow-up: Tirzepatide and nausea: is the profile genuinely different or just… Replied, post #79 · Compounds › Tirzepatide · 23 May 2026 · 3 likes Research-use-only tirzepatide is not approved for human use and is not made to pharmaceutical standards. Anyone discussing it here is describing what they did, not…
Cold solution and stinging: the simplest fix Replied, post #22 · Practice › Administration · 5 May 2026 · 19 likes On post #20 — agreed on the reasoning, with one qualification. My understanding of cold solution and stinging is a few years old and may have been superseded. If it has…
Reading a home test result without over-claiming Replied, post #28 · Analytics › Home & field testing · 1 May 2026 · 18 likes Adding the measurement that post #27 says would settle it. What you can use home tests for: confirmation that a solution contains peptide (as opposed to being saline…
Solubility limits and what a cloudy solution is telling you Replied, post #8 · Pharmacology › Formulation chemistry · 24 Apr 2026 · 0 likes Post #7 is the version of this I will quote in future. One addition. The bit of solubility limits that nobody enjoys is that the answer changes depending on what you…
Journal club: is percentage weight change the right endpoint? Replied, post #80 · Evidence › Journal club · 18 Apr 2026 · 0 likes Everything in post #78 holds. The case it does not cover is the one I have. The baseline characteristics table is the single most useful page for the questions that get…
Spike-and-recover accuracy for a peptide assay Replied, post #101 · Analytics › Method validation · 10 Apr 2026 · 0 likes Adding the boring version of spike-and-recover accuracy, because the interesting version keeps getting posted and the boring one is usually right. Check the ordinary…
Why the absence of controlled human data on BPC-157 matters more than people admit Replied, post #9 · Compounds › Repair & healing peptides · 8 Apr 2026 · 0 likes The lyophilised cake is worth looking at before adding diluent. A collapsed or shrunken cake is not a purity finding but it does say something about how the vial was…
Revisiting: Absolute versus relative contraindications Replied, post #51 · Safety › Contraindications · 25 Mar 2026 · 13 likes Taking post #48 at face value and following it one step further. Interaction-based contraindications are compound-pair specific and are the ones most often generalised…
[2026 update] Regional warehouse stock versus direct despatch Replied, post #22 · Sourcing › Logistics · 21 Mar 2026 · 2 likes Peak periods and public holidays affect this more than any other factor and are entirely predictable in advance. I checked the source rather than the summary, and they…
Lean mass preservation: what the evidence supports — does this still hold? Replied, post #42 · Outcomes › Body composition · 15 Mar 2026 · 23 likes Small methodological point on Lean mass preservation: repeating a measurement is cheap and resolves most of what is being argued about here at no cost to anyone.
Coming back to: Semaglutide in people without diabetes: what the evidence base looks like Replied, post #40 · Compounds › Semaglutide · 13 Mar 2026 · 12 likes Building on post #37 rather than restating it. Semaglutide versus liraglutide in STEP 8: semaglutide produced greater weight reduction and the discontinuation rates…
Nausea profile of amylin analogues compared with GLP-1 agonists Replied, post #60 · Compounds › Cagrilintide & amylin analogues · 12 Mar 2026 · 0 likes Post #56 describes the usual case. This is about the unusual one. Comparing an amylin analogue to an incretin agonist on weight change alone misses that they were…
About the COA interpretation category Replied, post #5 · Analytics › COA interpretation · 5 Mar 2026 · 28 likes Grateful for the specificity. Vague answers to this question are what sent me looking.
Why "dose equivalence" between different incretin analogues is a weak concept Replied, post #108 · Practice › Dosing & titration · 20 Feb 2026 · 3 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…
Mass error in ppm: the arithmetic and the caveat Replied, post #83 · Analytics › Mass spectrometry · 14 Feb 2026 · 15 likes Common adducts: sodium adds ≈22, potassium adds ≈38 compared to hydrogen. A [M+Na]+ peak is common and its mass is predictable from the base mass.
Mass error in ppm: the arithmetic and the caveat Replied, post #62 · Analytics › Mass spectrometry · 14 Feb 2026 · 0 likes Calibration state at the time of the run determines whether the ppm figure means anything. A report that states when the instrument was last calibrated is unusual and…
Trifluoroacetate content and its consequences Replied, post #53 · Analytics › Impurities & related substances · 31 Jan 2026 · 1 like Post #51 answers the question as asked. The question underneath it is different. Comparing impurity profiles across suppliers is much more informative than comparing…
Revisiting: A page that has drifted out of date and needs a maintainer Replied, post #31 · Documentation › Wiki requests · 10 Jan 2026 · 0 likes Following this. I have the same question and no better information than the first post.
Retatrutide's phase 2 heart-rate signal and how to think about it Replied, post #24 · Compounds › Retatrutide · 4 Jan 2026 · 16 likes Hepatic effects: glucagon receptor agonism promotes hepatic fat oxidation, which is mechanistically plausible for benefit in metabolic liver disease. Whether that…
[2026 update] Evidence quality in the secretagogue literature: an honest assessment Replied, post #4 · Compounds › Secretagogues & GH axis · 27 Dec 2025 · 0 likes Effects reported at the level of appetite are the most consistently described and the most mechanistically direct for the ghrelin-receptor compounds, which is not what…
[2026 update] What steady state means for the decision to escalate Replied, post #79 · Practice › Dosing & titration · 13 Nov 2025 · 0 likes Steady state means the plasma concentration is stable from dose to dose. That happens around 4 to 5 half-lives. Before that, the concentration is rising with each dose.…
What happens after your first post: likes, trust levels, and why none of it matters much… Replied, post #28 · Start Here › Welcome · 14 Oct 2025 · 4 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…
What happens after your first post: likes, trust levels, and why none of it matters much… Started this topic · Start Here › Welcome · 10 Oct 2025 · 0 likes The question in the title: What happens after your first post: likes, trust levels, and why none of it matters much — what changed since I will give what I have already…
Can a home kit substitute for a laboratory report? A careful no Replied, post #26 · Analytics › Home & field testing · 8 Oct 2025 · 3 likes Reconstitution behaviour is a legitimate home observation. A cake that will not dissolve, a solution that hazes, visible particulate — all are real information and all…
Follow-up: Why the titration planner refuses to produce a schedule below a floor Replied, post #126 · Data & Tools › Calculators · 23 Sep 2025 · 0 likes Helpful, and short, which on this subject is harder than long.
Reading SURMOUNT-1 without the press release Replied, post #14 · Compounds › Tirzepatide · 22 Sep 2025 · 22 likes SURMOUNT-1 reported weight reduction of a magnitude that was the largest for a pharmacological intervention at that time of publication. It also reported a clear dose…
[2026 update] Journal club: is percentage weight change the right endpoint? Replied, post #62 · Evidence › Journal club · 18 Aug 2025 · 15 likes Answering the question post #60 raises rather than the one it answers. Sessions on negative or null results are consistently the most instructive and the hardest to get…
Journal club: indirect comparison between two programmes, defended and attacked — one… Replied, post #29 · Evidence › Journal club · 16 Aug 2025 · 5 likes Building on post #26 rather than restating it. The figures usually contain the finding and the text usually contains the interpretation. Separating them for the first…
The "under review" status pill and when a moderator applies it — a second dataset Replied, post #17 · Evidence › Preprints · 16 Aug 2025 · 5 likes Adding the measurement that post #15 says would settle it. Unrefereed work is not worthless. A great deal of it survives review substantially unchanged. It is also the…
Documentation that appears only after payment Replied, post #2 · Sourcing › Red flags · 7 Aug 2025 · 1 like The opening post is the version of this I will quote in future. One addition. Adding a reference point for documentation. Mine is a single case, collected without…
[2026 update] Splitting an overlong document into two Replied, post #20 · Documentation › Wiki requests · 29 Jul 2025 · 8 likes Post #18 describes the usual case. This is about the unusual one. The most useful requests here identify a specific confusion that keeps recurring rather than a subject…
TB-500 and thymosin beta-4: the fragment versus the protein Replied, post #84 · Compounds › Repair & healing peptides · 29 Jul 2025 · 15 likes Post #83 answers the question as asked. The question underneath it is different. The claim about TB-500 and thymosin beta-4 upthread is stronger than its source…
When to stop reading forums, including this one Replied, post #3 · Wellbeing › Mental health · 1 Jul 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.
Revisiting: What to include when your question involves arithmetic Replied, post #9 · Start Here › How to Ask · 29 Jun 2025 · 15 likes On post #7 — agreed on the reasoning, with one qualification. Avoid "any advice?" at the end. It is so generic that people do not know which part of the post it refers…
Second pass at: Pen dose counters: what a click does and does not guarantee Replied, post #64 · Devices › Pens & autoinjectors · 12 Jun 2025 · 26 likes Travel with a pen raises a cold-chain question and a documentation question. The second is the one people forget until an airport. That is the version I would defend.…
Domestic fridge temperature mapping: a cheap experiment — what changed since Replied, post #111 · Devices › Cold chain · 27 May 2025 · 1 like Helpful, and short, which on this subject is harder than long.
Why the timeline is on the right and not the left Replied, post #21 · Meta › Site feedback · 24 May 2025 · 0 likes Reporting a real defect: on a long topic the jump-to-post link scrolls to the right post but the highlight does not fire on the first load. Second load is fine.…
When a preprint is the best available evidence and we say so — a second dataset Replied, post #21 · Evidence › Preprints · 3 May 2025 · 0 likes Worth separating two things that post #17 runs together. Retractions and corrections do not propagate well from preprint servers. A citation that was fine when made can…
[2026 update] Building a sensible monitoring schedule with your prescriber Replied, post #12 · Clinical › Bloodwork · 28 Apr 2025 · 7 likes Adding the measurement that post #10 says would settle it. Time of day: some biomarkers vary across the day. Cortisol in the morning differs from cortisol in the…
What SELECT changed about how semaglutide is discussed, and what it did not Replied, post #92 · Compounds › Semaglutide · 26 Apr 2025 · 2 likes Post #91 answers the question as asked. The question underneath it is different. The C-cell question: semaglutide triggered medullary thyroid carcinoma in rodent…
Coverage for the indication versus for the drug Replied, post #39 · Access › Insurance & coverage · 23 Apr 2025 · 1 like Reimbursement changes: a compound covered one year might not be the next. A formulary decision in January can change by April. Checking again before refilling saves…
A well-designed study with a badly written abstract Replied, post #13 · Evidence › Study critique · 7 Apr 2025 · 0 likes Worth separating two things that post #9 runs together. Hold a trial to the standard something could actually have met. A criticism that no achievable design could have…
Journal club: the retatrutide phase 2 obesity paper Started this topic · Evidence › Journal club · 6 Apr 2025 · 21 likes Journal club: the retatrutide phase 2 obesity paper — setting out what I have, and where I think it stops being reliable. Collecting what is known about retatrutide…
Why cagrilintide alone is discussed so much less than in combination Replied, post #34 · Compounds › Cagrilintide & amylin analogues · 26 Mar 2025 · 32 likes Published human data on cagrilintide alone is thinner than on the combination, which is the reverse of what most people assume from how it is discussed here.
Reading order for a first week here, and what to skip until later Replied, post #46 · Start Here › Welcome · 21 Mar 2025 · 10 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…
Assessing a warm arrival: the decision process Replied, post #8 · Sourcing › Logistics · 1 Mar 2025 · 0 likes Assessing a warm arrival 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 mass spectrometry cannot tell you about an epimer Replied, post #63 · Analytics › Mass spectrometry · 19 Feb 2025 · 3 likes Deamidation adds approximately one dalton and produces a species that frequently elutes very close to the parent. It is the hardest common impurity to see…
Distinguishing a deletion sequence by mass alone — the long version Replied, post #5 · Analytics › Mass spectrometry · 17 Feb 2025 · 10 likes Post #2 answers the question as asked. The question underneath it is different. Two sentences on Distinguishing a deletion sequence and then I will stop, because the…
Protein density versus volume when you cannot eat much Replied, post #92 · Nutrition & Training › Protein & intake · 8 Feb 2025 · 17 likes Liquid versus solid: protein in liquid form (shakes) is easier to consume in volume but might not be as satiating as solid food. Using both together can help.
A promotion I argued against, and why I lost Replied, post #89 · Documentation › Doc review · 7 Feb 2025 · 0 likes Reviewing your own nomination is fine and is not sufficient. Somebody else has to read it for the process to mean anything. The interesting part of this is the…
Protein density versus volume when you cannot eat much Replied, post #73 · Nutrition & Training › Protein & intake · 5 Feb 2025 · 18 likes Timing of protein: spreading protein intake across the day, with some at each meal, is more practical than trying to hit the whole target at one sitting on suppressed…
Second pass at: Regression to the mean in progress reports Replied, post #45 · Research Methods › Statistics · 4 Feb 2025 · 14 likes Regression to the mean explains a large share of apparent improvements in anything selected for being extreme. It is not a statistical curiosity; it is the default…
Coming back to: Reading a meta-analysis you disagree with, fairly Replied, post #21 · Evidence › Meta-analyses · 19 Jan 2025 · 15 likes A meta-analysis of four small trials is not stronger evidence than one adequately powered trial, whatever the summary statistic looks like. The uncertainty is in the…
Body image changing more slowly than the body Replied, post #91 · Wellbeing › Mental health · 21 Dec 2024 · 0 likes Worth stating the null on body image before we explain it: the observation may be nothing. That possibility deserves a sentence and usually does not get one.
[2026 update] New subcategory: rationale and scope Replied, post #52 · Meta › Announcements · 9 Dec 2024 · 0 likes Reading back through, this was answered upthread and I missed it. My fault.
EMA product information as a primary source — does this still hold? Replied, post #91 · Regional › European Union · 17 Nov 2024 · 2 likes This follows post #88 rather than contradicting it. Adding the boring version of EMA product information, because the interesting version keeps getting posted and the…
Why "any advice?" is the least effective ending for a post Replied, post #23 · Start Here › How to Ask · 10 Nov 2024 · 11 likes Context that matters: compound, how long in, current dose, relevant history. Context that does not matter: how you feel, your hopes for the outcome, your medical…
Transporting a vial for a weekend away Replied, post #15 · Practice › Storage & stability · 29 Oct 2024 · 31 likes I had written a reply contradicting post #11 and deleted it. Here is what survived. Two sentences on transporting a vial and then I will stop, because the rest is…
Second pass at: A field-by-field walk through a certificate of analysis Replied, post #78 · Analytics › COA interpretation · 8 Oct 2024 · 0 likes I had written a reply contradicting post #74 and deleted it. Here is what survived. "Not less than 98 per cent" is a specification. "98.3 per cent" is a result. A…
Revisiting: Melanocortin agonists: mechanism and the documented adverse profile Replied, post #39 · Compounds › Other compounds · 8 Oct 2024 · 0 likes On Melanocortin agonists, the part that usually goes wrong is that the question is asked as though it has one answer. It has a range, and the width of the range is the…
The topic list is dense — is that deliberate? Replied, post #30 · Meta › Site feedback · 25 Sep 2024 · 0 likes Posting my topic list numbers with the method attached so they can be discounted properly. Uncontrolled, unblinded, and collected by someone who wanted a particular…
Reporting a discrepancy without making an allegation Replied, post #80 · Sourcing › Vendor reports · 18 Sep 2024 · 32 likes Photograph the vial and the label before opening. It costs ten seconds and it is what turns a report into something checkable. One more caveat and then I will stop…
Gradient steepness and apparent purity: a worked comparison Replied, post #2 · Analytics › HPLC & UHPLC · 24 Aug 2024 · 2 likes A shoulder on the trailing edge is most often a closely related species rather than an artefact. The way to find out is to change the gradient slope, not to argue about…
Naming conventions for research peptides and the confusion they cause — one year on Replied, post #6 · Compounds › Other compounds · 2 Aug 2024 · 1 like Colour in a lyophilised cake is worth noting for the less common compounds specifically, because some of them are genuinely not white and a member expecting white will…
Where the four-week escalation interval comes from, and what it is not Replied, post #21 · Practice › Dosing & titration · 14 Jun 2024 · 11 likes Where I would push back on the four-week escalation interval consensus is the confidence, not the direction. The direction looks right. The confidence is borrowed.
Spreadsheets: an appreciation Replied, post #11 · Lounge › Off topic · 6 Jun 2024 · 16 likes The strongest argument against my own position on spreadsheets, stated as well as I can state it, since nobody else has yet.