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Unanswered questions

Questions with no answer at all. Not questions with no accepted answer — those are elsewhere.

739 questions · page 27 of 31

8 votes0 answers12k views
Is an escrowed payment sensible for an order shipping to Australia?

Details up front: an escrowed payment · Australia. The failure mode I am trying to avoid is making this decision emotionally. I have twelve months in view and I would…

payment-privacy
payment-privacy

Payment mechanics and their privacy properties: why suppliers ask for stablecoin transfers, what an on-chain transfer reveals, confirmation…

31 questions
group-buy
group-buy

Pooled purchasing: how the economics work, what trust structure a pool needs, splitting a single tested lot, and the failure modes when the…

41 questions
international-shipping
international-shipping

Cross-border movement of research material: transit lanes and their thermal profiles, tracked versus untracked, declaration accuracy, and what…

471 questions
asked by haze_check 9.3k · 2.0 years ago
4 votes0 answers5.1k views
Does a DEXA repeated every two weeks give me a usable lean-mass trend?

I have three DEXA scans on the same scanner at twelve-week intervals, fasted, same time of day. The comparison I want does not seem to exist anywhere in a form I can…

dexa
dexa

Dual-energy X-ray absorptiometry: what it measures, its precision limits, why hydration state and scan positioning move the numbers, and how to…

39 questions
lean-mass
lean-mass

Lean body mass as measured rather than assumed: what DEXA, BIA and air-displacement plethysmography each actually estimate, the body-composition…

127 questions
muscle-loss
muscle-loss

Loss of contractile tissue during energy deficit: what fraction of total loss is lean mass, why the commonly quoted figures are measurement…

39 questions
asked by fibre_or_fragment 13k · 2.0 years ago
12 votes0 answers14k views
What did STEP 5 do with participants who could not tolerate a step?

I have been on a stable schedule for eleven weeks, so this is not a first-week question. This is presented as though it settles something, and I am not convinced it…

titration
titration

Stepwise dose increases over weeks, why the label schedules exist at all, and what tolerability-driven deviation from a schedule looks like in…

456 questions
clinical-trials
clinical-trials

Reading the primary literature properly: estimands, intention-to-treat versus per-protocol, confidence intervals, absolute versus relative…

745 questions
gi-side-effects
gi-side-effects

The gastrointestinal cluster as a whole - nausea, vomiting, diarrhoea, constipation, reflux, early satiety - with trial incidence rates, dropout…

162 questions
asked by second_lot 9.4k · 2.0 years ago
25 votes0 answers17k views
Is an HJ order from Tianjin likely to hold cold chain to the United Kingdom?

The case in front of me: HJ · Tianjin · the United Kingdom. I want to decide this in advance so that I am not deciding it under pressure later. Assume I will follow…

cold-chain
cold-chain

Keeping material within a temperature window from manufacture to use: phase-change packs versus dry ice, thermal mass, transit-lane temperature…

578 questions
international-shipping
international-shipping

Cross-border movement of research material: transit lanes and their thermal profiles, tracked versus untracked, declaration accuracy, and what…

471 questions
vendor-comparison
vendor-comparison

Side-by-side comparison of suppliers on measurable axes - independently confirmed purity and content, lead time, cold-chain handling,…

388 questions
asked by harriet_lonsdale 35k · 2.0 years ago
28 votes0 answers16k views
How do I document a six-month lifestyle-intervention requirement?

I have the plan documents and the written criteria, which took two calls to obtain. I have read the obvious sources and they disagree with each other, so I would…

prior-authorization
prior-authorization

Prior authorisation mechanics: medical-necessity criteria, documenting a lifestyle-intervention requirement, step therapy, and the…

19 questions
insurance
insurance

Coverage: formulary tiers, exclusion versus non-coverage, the difference a diabetes indication makes, employer carve-outs, and what an appeal…

35 questions
nutrition
nutrition

Eating on a suppressed appetite: hitting nutritional targets inside a small energy budget, micronutrient risk, meal structure, and what the trial…

100 questions
asked by tare_weight 60k · 2.0 years ago
13 votes0 answers12k views
Does dimerisation dominate for a GLP-1 receptor agonist held at 25 °C?

Stated plainly: dimerisation · a GLP-1 receptor agonist · 25 °C. The empirical answer seems settled. The explanation does not. If the honest answer is that nobody…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

908 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

701 questions
hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

503 questions
asked by n_takahashi 29k · 2.0 years ago
21 votes0 answers30k views
Does fatigue at week seven of oral semaglutide usually resolve without a dose change?

The case in front of me: fatigue · seven · oral semaglutide. I can find plenty of assertions about this and almost no reasoning, which is usually a sign that nobody…

fatigue
fatigue

Tiredness on treatment: how much is energy deficit, how much is dehydration or electrolyte drift, how much is genuinely drug-attributable, and…

78 questions
titration
titration

Stepwise dose increases over weeks, why the label schedules exist at all, and what tolerability-driven deviation from a schedule looks like in…

456 questions
oral-glp1
oral-glp1

Oral routes for GLP-1 receptor agonism: peptide formulations rescued by absorption enhancers such as SNAC, and true small molecules that need no…

219 questions
asked by Dr_Lena_Ostrowska 38k · 2.0 years ago
37 votes0 answers51k views
Is 3.33 mg/mL a sensible working concentration for orforglipron, or should I go lower?

Numbers first: 3.33 mg/mL · orforglipron. I want to know what the trade-off actually is rather than which option is fashionable. I would rather have a defensible…

diluent-volume
diluent-volume

Choosing how much diluent to add, which is really a question about what you want your measurement resolution to be. Larger volumes buy you…

295 questions
reconstitution
reconstitution

Taking a lyophilised vial to a solution of known concentration: choice of diluent, volume selection, how to add liquid without shearing the cake,…

313 questions
dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
orforglipron
orforglipron

A non-peptide, orally bioavailable small-molecule GLP-1 receptor agonist studied in the ATTAIN programme. It is not a peptide, which changes…

219 questions
asked by linnea_wahlberg 17k · 2.0 years ago
14 votes0 answers14k views
How many vial-days does a 50 mg vial give at 20 mg/mL on a weekly schedule?

The particulars: 50 mg · 20 mg/mL. I would rather understand the derivation than memorise the outcome. Two people I asked gave two answers that differ by a factor of…

dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
cost-analysis
cost-analysis

Cost arithmetic done honestly: cost per milligram after dead-space loss, list versus net price, comparing a multi-dose vial to a fixed-dose pen,…

260 questions
diluent-volume
diluent-volume

Choosing how much diluent to add, which is really a question about what you want your measurement resolution to be. Larger volumes buy you…

295 questions
asked by cap_the_luer 14k · 2.0 years ago
5 votes0 answers8.2k views
Does splitting a 1 mg weekly dose of a GLP-1 receptor agonist across two administrations change anything?

What I am working with: 1 mg · a GLP-1 receptor agonist. I keep seeing this stated as a fact with no explanation attached, and unexplained facts make me suspicious.…

split-dosing
split-dosing

Dividing a weekly dose across more than one administration. Questions here concern the pharmacokinetic rationale, whether the peak-to-trough ratio…

44 questions
dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
glp1-mechanism
glp1-mechanism

Receptor-level pharmacology: GLP-1R as a class B GPCR, cAMP and PKA signalling, biased agonism, internalisation and resensitisation, and the…

132 questions
asked by ivo_paunovic 16k · 2.0 years ago
2 votes0 answers3.5k views
If I reconstitute a 2.5 mg vial with 1 mL of 0.9% sodium chloride, what concentration do I end up with?

Conditions: 2.5 mg · 1 mL · 0.9% sodium chloride. Please show the division. I want to check my own against yours. I would like the general form as well as the…

reconstitution
reconstitution

Taking a lyophilised vial to a solution of known concentration: choice of diluent, volume selection, how to add liquid without shearing the cake,…

313 questions
diluent-volume
diluent-volume

Choosing how much diluent to add, which is really a question about what you want your measurement resolution to be. Larger volumes buy you…

295 questions
dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
asked by Dr_Jonas_Halvorsen 28k · 2.0 years ago
38 votes0 answers38k views
How does ERP compare to GL Biochem (Shanghai) on documentation quality?

Stated plainly: ERP · GL Biochem (Shanghai). Both of these get recommended confidently by different people, which suggests neither is obviously right. My constraints…

vendor-comparison
vendor-comparison

Side-by-side comparison of suppliers on measurable axes - independently confirmed purity and content, lead time, cold-chain handling,…

388 questions
coa
coa

Certificates of analysis: what fields a useful one carries, how to tell a real analytical report from a marketing document, batch and lot…

771 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

454 questions
asked by carys_meredith 12k · 2.1 years ago
12 votes0 answers9.9k views
What does the mechanism of a GLP-1 receptor agonist predict that PIONEER-1 did not test?

Numbers first: a GLP-1 receptor agonist · PIONEER-1. I suspect the usual explanation for this is wrong, or at least incomplete. I am aware this may have a boring…

glp1-mechanism
glp1-mechanism

Receptor-level pharmacology: GLP-1R as a class B GPCR, cAMP and PKA signalling, biased agonism, internalisation and resensitisation, and the…

132 questions
clinical-trials
clinical-trials

Reading the primary literature properly: estimands, intention-to-treat versus per-protocol, confidence intervals, absolute versus relative…

745 questions
gip-receptor
gip-receptor

GIP receptor pharmacology, and the still-unsettled question of whether agonism or antagonism at GIPR is the metabolically useful direction.…

34 questions
asked by s_bhattacharya 31k · 2.1 years ago
24 votes0 answers22k views
What did the placebo arm of SURMOUNT-1 report for nausea?

What I have: SURMOUNT-1 · nausea. This is presented as though it settles something, and I am not convinced it does. I have two documents that appear to disagree,…

clinical-trials
clinical-trials

Reading the primary literature properly: estimands, intention-to-treat versus per-protocol, confidence intervals, absolute versus relative…

745 questions
nausea
nausea

The dominant tolerability signal in every trial of the class: incidence, timing relative to a dose step, duration, and the distinction between…

55 questions
asked by lane_transit 60k · 2.1 years ago
29 votes0 answers11k views
Why do two papers on STEP 4 report different headline figures?

The clinician who ordered the panel was not concerned; I would still like to understand it. This is one of those things that everyone repeats and nobody derives. This…

clinical-trials
clinical-trials

Reading the primary literature properly: estimands, intention-to-treat versus per-protocol, confidence intervals, absolute versus relative…

745 questions
dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
semaglutide
semaglutide

A GLP-1 receptor agonist with a fatty-acid-acylated backbone and a roughly one-week half-life, marketed for type 2 diabetes and for weight…

470 questions
asked by ines_brandt 113k · 2.1 years ago
8 votes0 answers10k views
Can I reconstitute retatrutide at 8 mg/mL and still measure a small dose accurately?

What I am working with: retatrutide · 8 mg/mL. I am trying to build something sustainable rather than something thorough that I will abandon. I have already decided…

diluent-volume
diluent-volume

Choosing how much diluent to add, which is really a question about what you want your measurement resolution to be. Larger volumes buy you…

295 questions
insulin-syringe
insulin-syringe

U-100 and U-40 insulin syringes as measuring instruments. A U-100 syringe is graduated in insulin units where 100 units equals 1 mL, so one unit…

244 questions
dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
retatrutide
retatrutide

An investigational GLP-1, GIP and glucagon receptor tri-agonist, studied in the TRIUMPH programme. Not approved anywhere. Use this tag for…

251 questions
asked by Dr_Otto_Lindqvist 72k · 2.1 years ago
24 votes0 answers19k views
Can I reconstitute a GLP-1 receptor agonist at 4 mg/mL and still measure a small dose accurately?

What I have: a GLP-1 receptor agonist · 4 mg/mL. This is a planning question. I know what my options are; I do not know how to weigh them. What I want is the minimum…

diluent-volume
diluent-volume

Choosing how much diluent to add, which is really a question about what you want your measurement resolution to be. Larger volumes buy you…

295 questions
insulin-syringe
insulin-syringe

U-100 and U-40 insulin syringes as measuring instruments. A U-100 syringe is graduated in insulin units where 100 units equals 1 mL, so one unit…

244 questions
dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
asked by threadlock7 19k · 2.1 years ago
27 votes0 answers25k views
How does Homopeptide compare to Wuhan Wansheng Biotechnology on documentation quality?

Conditions: Homopeptide · Wuhan Wansheng Biotechnology. I would like the axes of comparison first and the recommendation second. I have tried the first option and it…

vendor-comparison
vendor-comparison

Side-by-side comparison of suppliers on measurable axes - independently confirmed purity and content, lead time, cold-chain handling,…

388 questions
coa
coa

Certificates of analysis: what fields a useful one carries, how to tell a real analytical report from a marketing document, batch and lot…

771 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

454 questions
asked by haze_check 9.3k · 2.1 years ago
5 votes0 answers4.4k views
How long does retatrutide stay within specification at 30 °C once reconstituted?

Stated plainly: retatrutide · 30 °C. This is a procedural question rather than a theoretical one, and I would like the procedure rather than the theory. What I have…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

908 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

701 questions
shelf-life
shelf-life

How long a preparation remains within specification: labelled expiry for a sealed lyophilised vial, beyond-use dating after reconstitution, and…

327 questions
retatrutide
retatrutide

An investigational GLP-1, GIP and glucagon receptor tri-agonist, studied in the TRIUMPH programme. Not approved anywhere. Use this tag for…

251 questions
asked by loss_on_drying 40k · 2.1 years ago
21 votes0 answers26k views
What is the reported incidence of vomiting at the top studied dose?

It has now persisted for three weeks, which is what moved this from tolerable to worth asking about. This is presented as though it settles something, and I am not…

vomiting
vomiting

Emesis as a reported adverse event: trial incidence, its relationship to dose escalation rate, dehydration risk, and when it stops being a…

57 questions
clinical-trials
clinical-trials

Reading the primary literature properly: estimands, intention-to-treat versus per-protocol, confidence intervals, absolute versus relative…

745 questions
gi-side-effects
gi-side-effects

The gastrointestinal cluster as a whole - nausea, vomiting, diarrhoea, constipation, reflux, early satiety - with trial incidence rates, dropout…

162 questions
asked by wren_calloway 23k · 2.1 years ago
36 votes0 answers22k views
Is a 97.6% result from VendorInvestigate comparable to 96.8% from PeptideMeter?

The case in front of me: 97.6% · VendorInvestigate · 96.8% · PeptideMeter. These are treated as interchangeable and I do not think they are. If both are acceptable I…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

833 questions
batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

910 questions
reference-standard
reference-standard

Certified reference materials and in-house standards: traceability, the certificate of the standard itself, system suitability, and why every…

185 questions
vendor-investigate
vendor-investigate

VendorInvestigate, an independent vendor review and verification service. Use this tag for questions about its verification criteria, what a…

113 questions
peptidemeter
peptidemeter

PeptideMeter, an independent peptide analytics and vendor-rating service. Use this tag for its published datasets, its rating methodology, and how…

107 questions
asked by ruaidhri_o_shea 25k · 2.1 years ago
14 votes0 answers16k views
Is an 18G drawing needle the right choice for drawing semaglutide at 20 mg/mL?

The specifics, since they change the answer: an 18G drawing needle · semaglutide · 20 mg/mL. I am trying to choose between two options that are usually discussed as…

needle-gauge
needle-gauge

Gauge and length selection, the trade-off between draw time and tissue trauma, coring risk with larger-bore needles, and why a fixed-needle…

91 questions
injection-technique
injection-technique

Technique questions: angle, pinch versus flat, aspiration, injection speed, air bubbles, and the handling steps that determine whether you deliver…

96 questions
dead-space
dead-space

The volume trapped in the syringe hub and needle after the plunger bottoms out. It is small in absolute terms and large as a fraction of a small…

117 questions
semaglutide
semaglutide

A GLP-1 receptor agonist with a fatty-acid-acylated backbone and a roughly one-week half-life, marketed for type 2 diabetes and for weight…

470 questions
asked by tare_weight 60k · 2.1 years ago
41 votes0 answers48k views
Does the SELECT population resemble anyone asking about semaglutide here?

Concretely: SELECT · semaglutide. I want to understand what this actually establishes, as opposed to what it is being used to imply. My concern is that I am being…

clinical-trials
clinical-trials

Reading the primary literature properly: estimands, intention-to-treat versus per-protocol, confidence intervals, absolute versus relative…

745 questions
harm-reduction
harm-reduction

Reducing avoidable risk where a decision has already been made: independent verification before use, sterility practice, dose arithmetic checked…

472 questions
semaglutide
semaglutide

A GLP-1 receptor agonist with a fatty-acid-acylated backbone and a roughly one-week half-life, marketed for type 2 diabetes and for weight…

470 questions
asked by fill_volume 22k · 2.1 years ago
4 votes0 answers3.8k views
What has PeptideMeter published on CPC lots in the last year?

For reference: PeptideMeter · CPC. I want to understand what this actually establishes, as opposed to what it is being used to imply. My concern is that I am being…

vendor-investigate
vendor-investigate

VendorInvestigate, an independent vendor review and verification service. Use this tag for questions about its verification criteria, what a…

113 questions
batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

910 questions
vendor-comparison
vendor-comparison

Side-by-side comparison of suppliers on measurable axes - independently confirmed purity and content, lead time, cold-chain handling,…

388 questions
peptidemeter
peptidemeter

PeptideMeter, an independent peptide analytics and vendor-rating service. Use this tag for its published datasets, its rating methodology, and how…

107 questions
asked by rota_site 36k · 2.1 years ago