a.hartmann

TL2 Moderator · Seville

Contributes reviews on supplier material. Based in Seville.

Joined 25 August 2025 · last posted 20h

88 posts, newest first. Showing up to 150.

Shakes versus food: a pragmatic assessment Replied, post #27 · Nutrition & Training › Protein & intake · 27 Jul 2026 · 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…
Reading order for a first week here, and what to skip until later — what changed since Replied, post #85 · Start Here › Welcome · 26 Jul 2026 · 21 likes There is no stupid-questions rule and no penalty for asking badly. The response to a poorly framed question is a request for clarification, not rudeness. That is a…
How to ask about something you suspect is a bad idea — a second dataset Started this topic · Start Here › How to Ask · 15 Jul 2026 · 0 likes How to ask about something you suspect is a bad idea — a second dataset — that is the question, and I have not found it answered plainly anywhere I have looked.…
Coming back to: Delayed gastric emptying and oral medication absorption: which drugs… Replied, post #24 · Practice › Interactions · 14 Jul 2026 · 0 likes Picking up post #21: that is the part I would want checked first. Insulin interaction: semaglutide and tirzepatide are not contraindicated with insulin but the…
What a certificate commits its issuer to — one year on Replied, post #103 · Analytics › COA interpretation · 5 Jul 2026 · 5 likes Coming back to post #101, because the follow-up matters more than the original answer. Two things before anyone answers the substance. First, the context in the first…
[2026 update] Interpreting a result that disagrees with the supplier's certificate Replied, post #38 · Sourcing › Independent verification · 24 Jun 2026 · 0 likes Interpreting a result: a purity figure is one measurement on one vial on one day. Agreement across two services is much stronger. A single high number does not…
Endotoxin and why it is a separate question from purity — what changed since Replied, post #55 · Analytics › Impurities & related substances · 23 Jun 2026 · 0 likes Incomplete deprotection: mass higher by the protecting group mass. Usually markedly later eluting. A synthesis artifact from incomplete removal of protecting groups.
Prescription portability between countries Replied, post #72 · Access › International · 21 Jun 2026 · 0 likes Licensed prescribing: where a compound is approved, prescribing is restricted to licensed prescribers. Where it is not approved, the legality of possession and use is…
[2026 update] Area percent versus weight percent: the confusion that causes most arguments Replied, post #59 · Analytics › HPLC & UHPLC · 17 Jun 2026 · 12 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…
Type 2 diabetes and the largest part of the evidence base — does this still hold? Replied, post #15 · Clinical › Comorbidities · 17 Jun 2026 · 0 likes Multiple comorbidities: a person with diabetes, kidney disease, and cardiovascular disease is outside the studied populations in most trials. Extrapolating to that…
An appeal that succeeded, with the letter structure — the long version Replied, post #93 · Access › Insurance & coverage · 13 Jun 2026 · 23 likes post #92 answers the question as asked. The question underneath it is different. Coverage for weight management versus diabetes: many formularies cover these compounds…
Injecting into an area that has become firm: why not to Replied, post #34 · Practice › Administration · 8 Jun 2026 · 0 likes Air bubbles in a subcutaneous injection: the honest risk assessment is low. Tiny air bubbles in subcutaneous tissue do not behave like an air embolism in a blood…
Reading a trial's population section before its results Replied, post #75 · Evidence › Trials · 1 Jun 2026 · 28 likes Coming back to post #73, because the follow-up matters more than the original answer. Having read the exchange above, I think I was wrong earlier in this topic and I…
Follow-up: A parcel that arrived warm: a decision process, not a verdict Replied, post #48 · Practice › Storage & stability · 29 May 2026 · 30 likes Freeze-thaw: some peptide solutions tolerate freezing poorly because ice crystals damage protein structure. Whether your specific solution tolerates it depends on the…
[2026 update] Storing lyophilised material long term: what governs the shelf life Replied, post #124 · Practice › Storage & stability · 28 May 2026 · 19 likes Temperature excursions: if a vial sat at room temperature for a time, the question is whether the excursion was long enough to cause damage. Hours at room temperature…
Revisiting: Primary endpoint hierarchies and why order matters Started this topic · Evidence › Trials · 3 May 2026 · 43 likes Posting this under the heading it deserves: Revisiting: Primary endpoint hierarchies and why order matters Everything below is what sits behind that. Comparing…
Semaglutide and gastric emptying — the mechanism behind most of the side-effect profile Replied, post #14 · Compounds › Semaglutide · 2 May 2026 · 24 likes post #13 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 oral semaglutide needs an absorption enhancer at all — one year on Replied, post #11 · Compounds › Oral incretins · 17 Apr 2026 · 9 likes The SOUL trial: cardiovascular outcomes trial for oral semaglutide in people with type 2 diabetes and cardiovascular disease or chronic kidney disease. It demonstrates…
Subgroup analyses: pre-specified versus discovered — a second dataset Replied, post #46 · Evidence › Trials · 15 Apr 2026 · 0 likes Coming back to post #44, because the follow-up matters more than the original answer. Intent-to-treat versus per-protocol: ITT includes everyone assigned regardless of…
[2026 update] 0.3 mL versus 0.5 mL versus 1 mL barrels: resolution matters Replied, post #24 · Devices › Syringes & needles · 12 Apr 2026 · 0 likes Dead volume: residual liquid in the hub and needle after withdrawal. Typical residual is 0.01 to 0.02 mL for an insulin syringe with a fixed needle. Accounting for it…
The "under review" status pill and when a moderator applies it Replied, post #59 · Evidence › Preprints · 7 Apr 2026 · 16 likes I read post #57 twice before replying, because I had assumed the opposite. Server repositories: medRxiv for medicine, bioRxiv for biology. Preprints on these servers…
Stepping down deliberately, and how to do it without losing progress Replied, post #86 · Practice › Dosing & titration · 4 Apr 2026 · 8 likes post #85 answers the question as asked. The question underneath it is different. Stepping down deliberately: the withdrawal trials show that stopping is followed by…
Journal club: is percentage weight change the right endpoint? Replied, post #32 · Evidence › Journal club · 2 Apr 2026 · 0 likes SURMOUNT-1 (N Engl J Med 2022): Tirzepatide obesity trial. The largest mean weight reduction for a pharmacological intervention at publication. Read the categorical…
Managing an unplanned gap in supply Replied, post #75 · Access › Shortages · 27 Mar 2026 · 0 likes post #74 is right about the mechanism and I think understates the practical bit. Compounding during shortages: some jurisdictions allow pharmacy compounding when a…
Choosing which test to pay for, given a fixed budget Replied, post #28 · Sourcing › Independent verification · 17 Mar 2026 · 3 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…
Measurement error in home scales, with a worked standard deviation Replied, post #25 · Research Methods › Statistics · 16 Mar 2026 · 15 likes Effect sizes: the magnitude of a difference, not just whether it is statistically significant. A difference that is significant (p
Second pass at: What "verified" means on our vendor pages, stated narrowly Replied, post #78 · Sourcing › Vendor reports · 7 Mar 2026 · 0 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…
A history of disordered eating: proceeding carefully Replied, post #75 · Wellbeing › Mental health · 27 Jan 2026 · 0 likes Identity and self-image: for some people, weight and body size are central to identity. Large change to body size can affect identity. This is not pathological; it is…
The headache that turns out to be dehydration Replied, post #146 · Nutrition & Training › Hydration & electrolytes · 20 Jan 2026 · 5 likes Worth separating two things that post #142 runs together. The very ordinary causes of week-two malaise: inadequate hydration, low sodium intake, too-rapid calorie…
Rotating between abdomen, thigh and upper arm: absorption differences — one year on Replied, post #10 · Practice › Administration · 17 Jan 2026 · 1 like Angle of injection: 90 degrees into pinched tissue ensures subcutaneous placement. It is not always necessary and shallower angles can work, but 90 degrees into a small…
Request: a diff view for wiki revisions — the long version Replied, post #99 · Meta › Feature requests · 14 Jan 2026 · 0 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…
Anxiety in the first weeks: drug, situation, or both — what changed since Replied, post #71 · Wellbeing › Mental health · 2 Jan 2026 · 5 likes 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;…
Reading SURMOUNT-1 without the press release Replied, post #122 · Compounds › Tirzepatide · 31 Dec 2025 · 27 likes Titration schedules for tirzepatide have more dose steps than semaglutide partly because the compound is more potent and partly because the clinical programme used a…
Why an oral GLP-1 agonist is a formulation achievement more than a chemistry one Replied, post #104 · Compounds › Oral incretins · 22 Dec 2025 · 27 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…
Freeze-thaw and why one cycle is not the same as five Replied, post #23 · Practice › Storage & stability · 15 Nov 2025 · 0 likes Picking up post #20: that is the part I would want checked first. Dating prepared solutions: write the date reconstitution on the vial in permanent marker. If you later…
Where to report an adverse event officially, by region — a second dataset Replied, post #114 · Safety › Adverse events · 10 Nov 2025 · 0 likes Medullary thyroid carcinoma is the reason these compounds are contraindicated in people with personal or family history of MTC or multiple endocrine neoplasia type 2.…
High-resolution MS on aggregates and what it can see Replied, post #114 · Analytics › Mass spectrometry · 7 Nov 2025 · 11 likes Worth separating two things that post #110 runs together. What mass accuracy establishes: the measured mass is consistent with a specific composition. What it does not…
Coming back to: Resolution and tailing factor: real acceptance criteria Replied, post #109 · Analytics › HPLC & UHPLC · 16 Oct 2025 · 33 likes On post #105 — agreed on the reasoning, with one qualification. Method validation is the demonstration that a method can separate the compound from its degradation…
What the GIP component of tirzepatide is thought to contribute, and how confident we can… Replied, post #52 · Compounds › Tirzepatide · 10 Oct 2025 · 3 likes post #51 answers the question as asked. The question underneath it is different. For anyone arriving from a search: the marked solution above is the direct answer, and…
Power cut for eleven hours: how I assessed it afterwards Replied, post #86 · Practice › Storage & stability · 7 Oct 2025 · 17 likes Worth separating two things that post #82 runs together. Two things before anyone answers the substance. First, the context in the first post is clear and specific.…
Citing a preprint in a maintained document: our rule and its reasoning — does this still… Replied, post #101 · Evidence › Preprints · 3 Oct 2025 · 0 likes Picking up post #98: that is the part I would want checked first. Do not build anything on a preprint that you would mind rebuilding: if the preprint later changes…
Reading a supplier's product description as a marketing document Replied, post #78 · Compounds › Other compounds · 2 Oct 2025 · 17 likes Reading a supplier's product description as a marketing document: that is exactly what it is. The hyperbole, the mechanism written as fact, the theoretical benefits…
Second pass at: Programming during a large energy deficit Replied, post #19 · Nutrition & Training › Resistance training · 26 Sep 2025 · 0 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…
Payment method and the leverage it gives you, ranked Replied, post #75 · Sourcing › Payments · 25 Sep 2025 · 0 likes Worth separating two things that post #71 runs together. Currency conversion: payment in your local currency often involves a conversion fee. Paying in the supplier's…
Where the integrator drew the baseline, and how much it moved the number Replied, post #9 · Analytics › HPLC & UHPLC · 21 Sep 2025 · 0 likes Area percent is not mass percent. It is a proportion of absorbance, weighted by each species' extinction coefficient. For closely related impurities the approximation…
Coming back to: Where the integrator drew the baseline, and how much it moved the number Started this topic · Analytics › HPLC & UHPLC · 12 Sep 2025 · 0 likes On the subject in the title: Where the integrator drew the baseline, and how much it moved the number Working notes rather than a conclusion. Posting the method first,…
About the Site feedback category Replied, post #4 · Meta › Site feedback · 10 Sep 2025 · 6 likes 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…
Adolescents: a distinct evidence base — one year on Replied, post #14 · Clinical › Special populations · 5 Sep 2025 · 20 likes Medullary thyroid carcinoma history: an absolute contraindication because of the preclinical findings in rodent toxicology. The history (personal or family, especially…
Tirzepatide molecular mass and the charge states you would expect on ESI Replied, post #9 · Compounds › Tirzepatide · 24 Aug 2025 · 5 likes Storage and stability: published data on licensed tirzepatide formulations exists and is worth reading directly rather than through summarised claims. Reconstituted…
Fatigue in the first month: how much is the drug and how much is intake — what changed… Replied, post #32 · Practice › Side effects · 13 Aug 2025 · 4 likes I read post #30 twice before replying, because I had assumed the opposite. Having read the exchange above, I think I was wrong earlier in this topic and I want to say…
Travel coolers and how long they really hold Replied, post #80 · Devices › Cold chain · 8 Aug 2025 · 24 likes Assessing an excursion: if a package sat at room temperature for a time, visual inspection (cloudiness, discoloration, particles) can alert you to problems. Not visible…
Reading a combination trial: attributing effect to components Replied, post #2 · Compounds › Cagrilintide & amylin analogues · 8 Aug 2025 · 33 likes Nausea profile of amylin analogues: the historical agent pramlintide required multiple daily doses and had a difficult tolerability profile. A weekly formulation is a…
Promotion criteria, and the one that stops most nominations — the long version Replied, post #37 · Documentation › Doc review · 7 Aug 2025 · 22 likes On post #33 — agreed on the reasoning, with one qualification. Practical note that does not fit anywhere else. Whatever you conclude from this topic, write down what…
What a documentation review can and cannot tell you Replied, post #53 · Sourcing › Independent verification · 30 Jul 2025 · 0 likes How to submit a sample: contact the service directly. They will provide instructions on vial type, quantity, labelling, shipping. Following their instructions exactly…
Trial registration and comparing the protocol with the paper Replied, post #20 · Evidence › Trials · 8 Jul 2025 · 12 likes Coming back to post #18, because the follow-up matters more than the original answer. Practical note that does not fit anywhere else. Whatever you conclude from this…
Foaming during reconstitution and whether it matters Replied, post #18 · Practice › Reconstitution · 3 Jul 2025 · 26 likes Choosing a concentration on purpose rather than by accident: starting with "I want to draw 0.5 mL per dose" and working backward to the required concentration is more…
Coming back to: Official shortage notices and what they authorise Replied, post #23 · Access › Shortages · 6 Jun 2025 · 23 likes Supply interruptions: official shortage notices are published by regulatory agencies. That is the correct primary source rather than pharmacy rumors or forum discussion.
Pre-registering a personal experiment, seriously Replied, post #74 · Research Methods › N-of-1 designs · 1 Jun 2025 · 3 likes When to run an n-of-1: this design works when you want to know whether a treatment works for you, not whether it works in general. For that purpose, it is efficient.
Half-life, steady state, and accumulation worked through Replied, post #27 · Pharmacology › Pharmacokinetics · 26 May 2025 · 9 likes Renal clearance: these compounds are cleared partly via the kidney. In severe renal impairment, clearance is slowed and accumulation risk is higher. Dose adjustments…
A 5 mg vial and a 0.25 mg dose: the arithmetic in full — the long version Replied, post #117 · Practice › Reconstitution · 26 May 2025 · 0 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…
Asking about a compound your prescriber has not heard of Replied, post #47 · Clinical › Prescriber conversations · 24 May 2025 · 0 likes Worth separating two things that post #43 runs together. Understanding stopping rules: what would prompt stopping the compound? Adverse effect, lack of benefit after a…
DXA precision and the least significant change for lean mass — the long version Replied, post #49 · Outcomes › Body composition · 16 May 2025 · 0 likes For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.
[2026 update] What the GIP component of tirzepatide is thought to contribute, and how… Replied, post #55 · Compounds › Tirzepatide · 16 May 2025 · 0 likes This follows post #52 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…
Journal club: SURMOUNT-1, read without the press release Replied, post #113 · Evidence › Journal club · 9 May 2025 · 10 likes SOUL (N Engl J Med 2025): Oral semaglutide cardiovascular outcomes. Extends the cardiovascular evidence to the oral formulation. Note that oral bioavailability is lower…
Journal club: STEP 1 and the treatment-policy estimand — does this still hold? Replied, post #66 · Evidence › Journal club · 20 Apr 2025 · 31 likes STEP 1 (N Engl J Med 2021): The pivotal obesity trial for semaglutide and the reference point for most subsequent comparison. Mean weight reduction was substantially…
Reading order for a first week here, and what to skip until later Replied, post #86 · Start Here › Welcome · 16 Apr 2025 · 16 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…
Adjudicated events and why the definition matters — the long version Replied, post #84 · Evidence › Trials · 6 Apr 2025 · 0 likes Risk of bias: structured appraisal of internal validity. Key things to assess: randomisation method (was it truly random or could someone predict the next assignment),…
What SELECT changed about how semaglutide is discussed, and what it did not Replied, post #60 · Compounds › Semaglutide · 1 Apr 2025 · 11 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] US compounding rules and how they changed Replied, post #3 · Regional › North America · 8 Mar 2025 · 28 likes I read the opening post twice before replying, because I had assumed the opposite. Two things before anyone answers the substance. First, the context in the first post…
Distinguishing a deletion sequence by mass alone Replied, post #98 · Analytics › Mass spectrometry · 17 Feb 2025 · 3 likes Charge states observed: for semaglutide (4113.6 Da) the doubly charged ion appears at m/z ≈ 2057, triply charged at ≈ 1371, quadruply at ≈ 1029. Those are the positions…
Random versus fixed effects: choosing rather than defaulting — a second dataset Replied, post #105 · Evidence › Meta-analyses · 13 Feb 2025 · 4 likes Sensitivity analysis: the authors re-run the meta-analysis excluding studies one at a time, or by quality, to see whether the pooled estimate changes. Robust results…
Isotonicity and what happens when you get it wrong Replied, post #29 · Pharmacology › Formulation chemistry · 15 Jan 2025 · 18 likes Lyophilisation and reconstitution: the powder is stable for extended periods if kept cool and dry. Once reconstituted, stability decreases because the dissolved peptide…
Books and papers worth reading that are not about this at all Replied, post #13 · Lounge › Off topic · 6 Jan 2025 · 9 likes Newer drugs and mechanisms: when a new drug launches or a new mechanism is discovered, the Lounge is a place to discuss the news and speculate before hard data exists.
Sample size intuition for a personal experiment Replied, post #4 · Research Methods › Statistics · 30 Dec 2024 · 19 likes On the opening post — agreed on the reasoning, with one qualification. Relative risk and odds ratios: both compare the rate in one group to the rate in another.…
Coming back to: When to suspect the method rather than the sample Replied, post #136 · Analytics › Method validation · 26 Dec 2024 · 0 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…
Persistent vomiting and the threshold for seeking help — one year on Replied, post #21 · Safety › Adverse events · 20 Dec 2024 · 0 likes On post #17 — agreed on the reasoning, with one qualification. Severe gastrointestinal events: persistent vomiting, abdominal pain out of proportion, or signs of bowel…
Building a sensible monitoring schedule with your prescriber Replied, post #41 · Clinical › Bloodwork · 20 Dec 2024 · 13 likes Fasting state: some lab tests require fasting; others do not. Lipids on a fasting draw differ from lipids on a fed draw. Always note whether the test was fasting when…
[2026 update] New subcategory: rationale and scope Replied, post #22 · Meta › Announcements · 25 Nov 2024 · 8 likes Notifications: watching this subcategory means you receive notifications when announcements are posted. Useful if you want to stay current.
Reading a preclinical wound-healing model and its relevance to a human tendon Replied, post #82 · Compounds › Repair & healing peptides · 18 Nov 2024 · 19 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…
Research-use-only labelling: what it means and what it does not — the long version Replied, post #12 · Sourcing › Regulatory · 16 Oct 2024 · 2 likes Picking up post #9: that is the part I would want checked first. For anyone arriving from a search: the marked solution above is the direct answer, and the replies…
Irish differences from the UK position Replied, post #31 · Regional › UK & Ireland · 10 Oct 2024 · 10 likes On post #27 — agreed on the reasoning, with one qualification. Compounding pharmacies: UK allows compounding under specific conditions when a licensed product is…
Progressive overload when the scale is falling — one year on Replied, post #76 · Nutrition & Training › Resistance training · 21 Sep 2024 · 0 likes Programming while losing weight quickly: realistic expectations are crucial. Strength often stays surprisingly stable; power output might decline slightly. Expecting…
Circumference measurements as a poor man's composition estimate Replied, post #104 · Outcomes › Body composition · 28 Aug 2024 · 3 likes Visceral fat: DXA does not distinguish visceral (organ-associated) fat from subcutaneous fat. That distinction might matter but requires different imaging to measure.
Second pass at: A field-by-field walk through a certificate of analysis Replied, post #38 · Analytics › COA interpretation · 27 Aug 2024 · 0 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…
Reporting a discrepancy without making an allegation Replied, post #32 · Sourcing › Vendor reports · 18 Aug 2024 · 31 likes Picking up post #29: that is the part I would want checked first. I disagree with the reply above, and I think the disagreement is substantive rather than…
Coming back to: Purity assay versus content assay: two different numbers Replied, post #60 · Analytics › COA interpretation · 13 Aug 2024 · 15 likes Sterility testing is separate: chromatographic purity, mass spectrometry, and endotoxin testing all say nothing about whether a solution is sterile. If sterility…
Guidelines revision: what changed and why Replied, post #3 · Meta › Announcements · 24 Jul 2024 · 1 like I read the opening post twice before replying, because I had assumed the opposite. Feedback to announcements: if you have feedback on an announced change (not a…
Cold packs, phase-change material, and what survives ten days Replied, post #19 · Sourcing › Logistics · 16 Jun 2024 · 16 likes Picking up post #16: that is the part I would want checked first. Documentation after arrival: photograph the parcel and its contents on arrival. If something later…