l.vukovic

TL2 Moderator · Utrecht

Contributes reviews on supplier material. Based in Utrecht.

Joined 12 March 2025 · last posted 15h

79 posts, newest first. Showing up to 150.

Follow-up: External review after an internal denial Replied, post #11 · Access › Insurance & coverage · 27 Jul 2026 · 0 likes I read post #9 twice before replying, because I had assumed the opposite. Documentation your clinician can provide: letters from clinicians describing why standard…
Revisiting: Theoretical plates: useful number or ritual? Replied, post #20 · Analytics › HPLC & UHPLC · 18 Jul 2026 · 31 likes This is why a purity figure without the underlying chromatogram is weaker evidence than it appears. It is also why two competent laboratories can report different…
Semaglutide and gastric emptying — the mechanism behind most of the side-effect profile Replied, post #109 · Compounds › Semaglutide · 17 Jul 2026 · 33 likes Two things before anyone answers the substance. First, the context in the first post is clear and specific. Second, the question is framed so that an answer can…
[2026 update] Antibiotics and a course of something with delayed emptying Replied, post #35 · Practice › Interactions · 12 Jul 2026 · 0 likes Two things before anyone answers the substance. First, the context in the first post is clear and specific. Second, the question is framed so that an answer can…
Reference intervals: how they are constructed and why one in twenty flags — does this… Replied, post #14 · Clinical › Bloodwork · 8 Jul 2026 · 13 likes Biological variation: the person-to-person variation in a biomarker for a healthy person is larger than most people realize. Comparing your result to the reference…
What a reversed-phase purity number actually is Replied, post #17 · Analytics › HPLC & UHPLC · 2 Jul 2026 · 21 likes Before anything else: what was the gradient, and at what wavelength? Area percent at different wavelengths is not the same number even on the same sample because…
Coming back to: Specificity, linearity, accuracy, precision, range, robustness — with… Replied, post #71 · Analytics › Method validation · 29 Jun 2026 · 4 likes System suitability: injections run at the start of a batch to establish that the instrument and column are performing. Acceptance criteria typically include replicate…
[2026 update] Travelling with an injectable: documentation and practicalities Replied, post #14 · Access › International · 14 Jun 2026 · 27 likes Practical note that does not fit anywhere else. Whatever you conclude from this topic, write down what you did and when. The single most useful thing in your own…
Does a peptide degrade silently, with no visual change? Replied, post #47 · Practice › Storage & stability · 13 Jun 2026 · 32 likes Worth separating two things that post #43 runs together. Two things before anyone answers the substance. First, the context in the first post is clear and specific.…
What I would want from a home test that does not exist yet — what changed since Replied, post #52 · Analytics › Home & field testing · 12 Jun 2026 · 0 likes What physical quantity does the device measure? A colorimetric or lateral-flow method typically responds to a class of chemistry rather than to a specific molecule. It…
Coming back to: Why a preprint's supplementary material is often the best part Replied, post #76 · Evidence › Preprints · 11 Jun 2026 · 6 likes post #75 is right about the mechanism and I think understates the practical bit. I disagree with the reply above, and I think the disagreement is substantive rather…
Why we ask for units every single time, with three examples of what goes wrong Replied, post #24 · Start Here › How to Ask · 7 Jun 2026 · 10 likes On post #20 — agreed on the reasoning, with one qualification. The specific question in the title is more useful than you might think. A title like "a question I have"…
A certificate whose chromatogram axes do not match its stated method — one year on Replied, post #57 · Sourcing › Red flags · 5 Jun 2026 · 4 likes This follows post #54 rather than contradicting it. Thank you for the correction. I have edited my earlier post with a note rather than silently, so the thread still…
A supplier who responds to a discrepancy with silence — what changed since Replied, post #57 · Sourcing › Red flags · 3 Jun 2026 · 2 likes post #56 is right about the mechanism and I think understates the practical bit. Exaggerated claims without documentation: every compound has limits. No peptide is…
Spreadsheets: an appreciation — what changed since Replied, post #59 · Lounge › Off topic · 2 Jun 2026 · 12 likes Industry and supply chain: post about manufacturing, pharmaceutical economics, or market dynamics if you have something substantive to contribute.
Blind submission and why it changes minds — the long version Replied, post #104 · Sourcing › Independent verification · 28 May 2026 · 14 likes Picking up post #101: that is the part I would want checked first. Repeat testing: if you want to verify the same lot a second time, testing with a different service…
[2026 update] A vial that will not fully dissolve: what to check and in what order Replied, post #46 · Practice › Reconstitution · 10 May 2026 · 29 likes Worth separating two things that post #42 runs together. How much of the diluent volume the powder itself displaces: for a small peptide vial, the powder volume is…
0.3 mL versus 0.5 mL versus 1 mL barrels: resolution matters Replied, post #30 · Devices › Syringes & needles · 3 May 2026 · 0 likes Picking up post #27: that is the part I would want checked first. Needle length: typical lengths for subcutaneous injection are 4-6 mm (short), 8 mm (standard), or…
Constipation management, with a dietitian's contribution Replied, post #53 · Practice › Side effects · 15 Apr 2026 · 23 likes On post #49 — agreed on the reasoning, with one qualification. Gallbladder complications: rapid weight loss increases the risk of gallstone formation. The mechanism is…
Revisiting: The report format the maintainers ask for, and why each field is there Replied, post #51 · Sourcing › Vendor reports · 15 Apr 2026 · 4 likes I read post #49 twice before replying, because I had assumed the opposite. Lot matching: confirm the lot number on the certificate matches the lot number on the vial. A…
Measurement error in home scales, with a worked standard deviation — the long version Replied, post #77 · Research Methods › Statistics · 13 Apr 2026 · 1 like Absence of evidence and evidence of absence: if a study is small and finds no effect, that is absence of evidence, not evidence of absence. A larger study might find an…
Pregnancy and pregnancy planning: contraindication and washout Replied, post #91 · Clinical › Special populations · 30 Mar 2026 · 7 likes I read post #89 twice before replying, because I had assumed the opposite. Practical note that does not fit anywhere else. Whatever you conclude from this topic, write…
Second pass at: What pooling buys you and what it destroys Replied, post #32 · Evidence › Meta-analyses · 29 Mar 2026 · 17 likes post #31 answers the question as asked. The question underneath it is different. Number needed to treat from a meta-analysis: can be computed from the pooled estimate…
Second pass at: Metformin co-administration and additive GI effects Replied, post #73 · Practice › Interactions · 26 Mar 2026 · 16 likes On post #69 — agreed on the reasoning, with one qualification. Supplements and herbs: many have no established interaction. Some do. If you are taking something…
An ABAB design with a data table and honest limitations — a second dataset Replied, post #98 · Research Methods › N-of-1 designs · 24 Mar 2026 · 2 likes Generalisability: a robust n-of-1 result applies to you. It does not tell you much about whether the effect generalises to others similar to you, much less to people…
Journal club: orforglipron phase 2 and the non-peptide question Replied, post #17 · Evidence › Journal club · 15 Mar 2026 · 11 likes This follows post #14 rather than contradicting it. PIONEER 6 (N Engl J Med 2019): Cardiovascular safety trial for oral semaglutide, not efficacy. Non-inferiority for…
Splitting an overlong document into two Replied, post #7 · Documentation › Wiki requests · 11 Mar 2026 · 0 likes Authority and authorship: if you think a maintained page needs input from someone with specific expertise (a clinician, an analytical chemist) suggest who might…
Why this subcategory is stricter about sourcing than most Replied, post #6 · Compounds › Secretagogues & GH axis · 7 Mar 2026 · 16 likes Coming back to post #4, because the follow-up matters more than the original answer. Two things before anyone answers the substance. First, the context in the first…
Comparing the STEP programme populations: who was actually enrolled Started this topic · Compounds › Semaglutide · 7 Mar 2026 · 9 likes Comparing the STEP programme populations: who was actually enrolled Writing it up because I had to work it out twice and would rather nobody else did. Comparing STEP 1…
Interpreting a result that disagrees with the supplier's certificate Replied, post #136 · Sourcing › Independent verification · 24 Feb 2026 · 5 likes I disagree with the reply above, and I think the disagreement is substantive rather than terminological. The distinction being drawn does not survive when you look at…
[2026 update] Are there stupid questions here? A staff answer, at length Replied, post #20 · Start Here › Welcome · 10 Feb 2026 · 13 likes Thank you for the correction. I have edited my earlier post with a note rather than silently, so the thread still makes sense to read. The error was mine and it was the…
Citation sweep results: how many references did not say what was claimed Replied, post #35 · Meta › Wiki maintenance · 24 Jan 2026 · 0 likes Maintainer handovers: if a page's maintainer is inactive and needs a new one, discussing that here can facilitate the transition.
Second pass at: Pregnancy and pregnancy planning: contraindication and washout Replied, post #41 · Clinical › Special populations · 23 Jan 2026 · 2 likes Hypoglycemia risk: in people already on insulin or sulfonylureas, adding a GLP-1 agonist requires insulin dose reduction and close monitoring for hypoglycemia. This is…
[2026 update] What a purity-only report leaves out Replied, post #4 · Sourcing › Independent verification · 19 Jan 2026 · 4 likes post #2 answers the question as asked. The question underneath it is different. VendorInvestigate: documentation and supplier-practice review. Reviews paperwork rather…
Dizziness on standing and the electrolyte explanation — does this still hold? Replied, post #35 · Practice › Side effects · 14 Jan 2026 · 26 likes Delayed gastric emptying: the mechanism behind much of the gastrointestinal side-effect profile. At extreme magnitudes, severe gastroparesis is a rare but serious…
Reverse causation in a cohort study of weight and outcome Started this topic · Evidence › Study critique · 23 Dec 2025 · 12 likes On the subject in the title: Reverse causation in a cohort study of weight and outcome Working notes rather than a conclusion. Comparing SELECT ( N Engl J Med , 2023)…
Coming back to: Over-dilution: when your dose falls below one readable graduation Replied, post #86 · Practice › Reconstitution · 25 Nov 2025 · 1 like Swirling versus inverting versus leaving it alone: the vial can be gently warmed (hands around it) and swirled with a rolling motion. Vigorous shaking introduces air…
Revisiting: Why tirzepatide titration schedules have more steps than semaglutide's Replied, post #25 · Compounds › Tirzepatide · 9 Nov 2025 · 26 likes SURPASS-2 compared tirzepatide with semaglutide 1.0 mg, the licensed diabetes dose at that time. It did not compare with semaglutide 2.4 mg, the highest approved dose.…
Sleep quality changes during weight loss — what changed since Replied, post #50 · Wellbeing › Sleep · 4 Nov 2025 · 0 likes This follows post #47 rather than contradicting it. Sleep hygiene: basics (cool dark room, consistent sleep time, no screens before bed) matter more during energy…
AOD-9604 and the fragment hypothesis, revisited Replied, post #25 · Compounds › Other compounds · 3 Nov 2025 · 33 likes Distinguishing marketed research compounds from true chemical synthesis: some online suppliers sell compounds that are genuinely novel and difficult to obtain…
Sleep tracking data and its considerable limitations Replied, post #122 · Wellbeing › Sleep · 29 Oct 2025 · 26 likes Apnoea monitoring: if you have diagnosed or suspected sleep apnoea, periodic monitoring (annually) during weight loss is prudent because severity changes.
Documentation that materially improves an appeal's chances Replied, post #24 · Access › Insurance & coverage · 10 Oct 2025 · 23 likes Documentation your clinician can provide: letters from clinicians describing why standard treatments have failed or are contraindicated are often exactly what an…
Temperature loggers worth the money Replied, post #34 · Devices › Cold chain · 25 Sep 2025 · 16 likes Reconstituted solutions: once reconstituted, solutions are less stable than lyophilised powder. Refrigerate prepared solutions immediately after preparation. Most…
The nausea timeline across the first four weeks, with a tabulated log Replied, post #82 · Practice › Side effects · 22 Sep 2025 · 5 likes Delayed gastric emptying: the mechanism behind much of the gastrointestinal side-effect profile. At extreme magnitudes, severe gastroparesis is a rare but serious…
Reverse causation in a cohort study of weight and outcome — a second dataset Replied, post #89 · Evidence › Study critique · 15 Sep 2025 · 26 likes Practical note that does not fit anywhere else. Whatever you conclude from this topic, write down what you did and when. The single most useful thing in your own…
The nausea timeline across the first four weeks, with a tabulated log Replied, post #63 · Practice › Side effects · 15 Sep 2025 · 26 likes Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing. The correction was fair and I had…
How the vendor documentation pages are maintained, and by whom — what changed since Replied, post #42 · Sourcing › Vendor reports · 18 Aug 2025 · 11 likes Disputed records: when a result disagreed and was not explained, the record says disputed and stays that way. We do not remove inconvenient history; we document it.
Analytical identity of BPC-157: a 15-mer with a simple mass Replied, post #3 · Compounds › Repair & healing peptides · 17 Aug 2025 · 0 likes BPC-157: the preclinical literature is extensive, mostly from a small number of research groups, and reports effects across a wide range of injury models. The breadth…
Second pass at: Triple agonism: additive, synergistic, or neither? Replied, post #96 · Compounds › Retatrutide · 17 Aug 2025 · 13 likes What we do not know about retatrutide, listed explicitly: long-term safety, real-world response rates, the dose response in diverse populations, whether the heart-rate…
Freeze-thaw and why one cycle is not the same as five — a second dataset Replied, post #8 · Practice › Storage & stability · 17 Jul 2025 · 7 likes post #7 is right about the mechanism and I think understates the practical bit. Published stability data applies specifically to the formulation studied, under the…
Research-use-only labelling: what it means and what it does not Replied, post #11 · Sourcing › Regulatory · 12 Jul 2025 · 3 likes Research-use-only status is a legal classification, not a safety classification. It means the compound is sold for laboratory use and not for human consumption. The…
High-resolution MS on aggregates and what it can see Replied, post #12 · Analytics › Mass spectrometry · 26 Jun 2025 · 2 likes Resolution: "high resolution" commonly means
Second pass at: How to research a compound with no human data without deceiving yourself Replied, post #51 · Compounds › Other compounds · 7 May 2025 · 14 likes AOD-9604 is a fragment of human growth hormone and has been discussed as a potential weight-loss agent based on theoretical mechanism. The fragment hypothesis — that…
Domestic fridge temperature mapping: a cheap experiment — what changed since Replied, post #87 · Devices › Cold chain · 18 Apr 2025 · 1 like Domestic refrigeration: most lyophilised peptides are stored at 2–8 °C (35–46 °F). That is standard refrigerator temperature. Check your refrigerator's actual…
Obstructive sleep apnoea and a hard endpoint in this class Replied, post #59 · Clinical › Comorbidities · 15 Apr 2025 · 27 likes Interactions between comorbidities: diabetes and kidney disease together change the risk calculation for hypoglycemia and for medication clearance. They are not…
A 5 mg vial and a 0.25 mg dose: the arithmetic in full — the long version Replied, post #79 · Practice › Reconstitution · 14 Apr 2025 · 5 likes Arithmetic step by step: a 5 mg vial with 2 mL of diluent gives (5 mg) / (2 mL) = 2.5 mg/mL. On a U-100 syringe at that concentration, 100 units = 1 mL = 2.5 mg, so…
Documenting a supplier's response to a discrepancy — does this still hold? Replied, post #5 · Sourcing › Vendor reports · 18 Mar 2025 · 7 likes Pattern across lots: a single result is a data point. Three or four results from the same supplier showing a consistent pattern becomes a record worth discussing. Two…
Biased agonism: a real phenomenon, an over-used explanation Replied, post #120 · Pharmacology › Receptor biology · 18 Mar 2025 · 1 like I read post #118 twice before replying, because I had assumed the opposite. Species differences: rodent studies show the same compounds produce effects in rodents that…
Validating a method you did not develop — does this still hold? Replied, post #129 · Analytics › Method validation · 17 Mar 2025 · 11 likes Picking up post #126: that is the part I would want checked first. Specificity: the method can distinguish the intended compound from related impurities and degradation…
Charge states for a 4 kDa peptide, worked through Replied, post #116 · Analytics › Mass spectrometry · 15 Mar 2025 · 28 likes On post #112 — agreed on the reasoning, with one qualification. Resolution: "high resolution" commonly means
Consistent declarations and why they matter more than clever ones Replied, post #130 · Sourcing › Logistics · 5 Mar 2025 · 0 likes Two things before anyone answers the substance. First, the context in the first post is clear and specific. Second, the question is framed so that an answer can…
SNAC and the mechanism of oral peptide absorption — the long version Replied, post #32 · Compounds › Oral incretins · 25 Feb 2025 · 30 likes Oral versus injectable exposure: comparing a 14 mg oral dose with a 0.5 mg injectable dose is comparing apples to a different fruit. The oral bioavailability is low…
Anxiety in the first weeks: drug, situation, or both Replied, post #54 · Wellbeing › Mental health · 24 Feb 2025 · 1 like Body image and weight loss: large weight loss changes a person's relationship with their body in ways that can be psychologically complex. Some of that is positive;…
Canadian access and provincial variation Replied, post #37 · Regional › North America · 31 Jan 2025 · 15 likes I read post #35 twice before replying, because I had assumed the opposite. Canada: Health Canada licenses compounds. Prescribing is provincial. Compounds are…
Journal club: SUSTAIN 6 and its retinopathy signal — does this still hold? Replied, post #30 · Evidence › Journal club · 22 Jan 2025 · 13 likes This follows post #27 rather than contradicting it. Session format: read the paper before posting. The discussion is much better when everyone has. Start with the…
Revisiting: Semaglutide formulation: what is in the licensed product besides the peptide Replied, post #11 · Compounds › Semaglutide · 17 Dec 2024 · 0 likes Coming back to post #9, because the follow-up matters more than the original answer. The C-cell question: semaglutide triggered medullary thyroid carcinoma in rodent…
Coming back to: When to suspect the method rather than the sample Replied, post #21 · Analytics › Method validation · 3 Dec 2024 · 4 likes Linearity: the detector response is proportional to compound concentration across the working range. Demonstrated by running standards at multiple concentrations and…
Journal club: STEP 4 and what a withdrawal design can prove — one year on Replied, post #11 · Evidence › Journal club · 30 Nov 2024 · 0 likes TRIUMPH (ongoing): Retatrutide phase 3. No results yet. Nothing should be attributed to it because it has not finished. When it does, this discussion will return to it.
EMA product information as a primary source — does this still hold? Replied, post #7 · Regional › European Union · 14 Nov 2024 · 0 likes Spain: AEMPS is the regulator. Public reimbursement for weight management has been limited with regional variation in specialist pathways. Private prescription is common.
Revisiting: Melanocortin agonists: mechanism and the documented adverse profile Replied, post #107 · Compounds › Other compounds · 10 Nov 2024 · 3 likes I read post #105 twice before replying, because I had assumed the opposite. This subcategory exists because some people will research compounds outside the main groups…
Revisiting: How to bring a laboratory report to an appointment usefully Replied, post #154 · Clinical › Bloodwork · 29 Oct 2024 · 1 like Reference intervals: constructed to contain the central 95% of a reference population, which means one in twenty healthy people falls outside one by definition. Add…
Coming back to: Preparing for an appointment: one page, three questions Replied, post #77 · Clinical › Prescriber conversations · 14 Oct 2024 · 11 likes Coming back to post #75, because the follow-up matters more than the original answer. Discussing off-label dosing: if you want to dose differently than the label…
Revisiting: Melanocortin agonists: mechanism and the documented adverse profile Replied, post #21 · Compounds › Other compounds · 28 Sep 2024 · 7 likes I disagree with the reply above, and I think the disagreement is substantive rather than terminological. The distinction being drawn does not survive when you look at…
Coming back to: What consumer-accessible tests can and cannot determine Replied, post #9 · Analytics › Home & field testing · 27 Sep 2024 · 0 likes This follows post #6 rather than contradicting it. What physical quantity does the device measure? A colorimetric or lateral-flow method typically responds to a class…
Correlation in a self-tracked dataset: what it can support Replied, post #69 · Research Methods › Statistics · 23 Aug 2024 · 10 likes Absence of evidence and evidence of absence: if a study is small and finds no effect, that is absence of evidence, not evidence of absence. A larger study might find an…
Coming back to: Purity assay versus content assay: two different numbers Replied, post #25 · Analytics › COA interpretation · 9 Aug 2024 · 0 likes I read post #23 twice before replying, because I had assumed the opposite. Water content (residual moisture) matters: lyophilised peptide is not dry. A few percent…
The most common factual error about semaglutide on the internet Replied, post #2 · Compounds › Semaglutide · 8 Jul 2024 · 12 likes Coming back to the opening post, because the follow-up matters more than the original answer. The mass figure differs between sources because of how the different…
Assessing a warm arrival: the decision process — one year on Replied, post #62 · Sourcing › Logistics · 30 May 2024 · 0 likes post #61 answers the question as asked. The question underneath it is different. Reshipment after seizure: if a parcel is seized, some suppliers will reship; others…
Where the four-week escalation interval comes from, and what it is not Replied, post #9 · Practice › Dosing & titration · 30 May 2024 · 18 likes Titrating on tolerability rather than on the calendar: some people escalate when they tolerate a dose well, others escalate on the prescribed schedule regardless. The…