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Unanswered questions

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

739 questions · page 30 of 31

8 votes0 answers7.3k views
What is the dead-space loss per draw with a 27G needle at 20 mg/mL?

Concretely: a 27G needle · 20 mg/mL. I want the working, not the result — I need to be able to redo it with different numbers. I care about the precision as well as…

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
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 cake_intact 17k · 2.3 years ago
6 votes0 answers6.1k views
What is the thermal exposure on a Zhuhai to the Netherlands lane in summer?

Stated plainly: Zhuhai · the Netherlands. I have the document in front of me and I can read the numbers. What I cannot do is interpret them. I am reasonably…

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
storage
storage

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

701 questions
asked by zeynep_arslan 16k · 2.3 years ago
20 votes0 answers13k views
Why would Janoshik report 98.8% where the supplier certificate says something higher?

What I am working with: Janoshik · 98.8%. I noticed this today and I have not touched anything since, in case the state is diagnostic. I have not discarded anything…

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
hplc
hplc

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

503 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
janoshik
janoshik

Janoshik Analytical, an independent third-party testing laboratory widely used by this community for HPLC purity, identity and quantified content…

139 questions
asked by ben_akintola 10k · 2.3 years ago
29 votes0 answers42k views
Is there any reason to reconstitute at 5 mg/mL rather than 2 mg/mL?

I have photographs before and after reconstitution if the visual detail matters. I would like the axes of comparison first and the recommendation second. I have tried…

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
asked by priya_menon 13k · 2.3 years ago
28 votes0 answers20k views
Is a 29G needle the right choice for drawing survodutide at 20 mg/mL?

The specifics, since they change the answer: a 29G needle · survodutide · 20 mg/mL. The comparison I want does not seem to exist anywhere in a form I can evaluate. I…

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
survodutide
survodutide

A GLP-1 and glucagon receptor dual agonist with a substantial published MASH dataset. Use this tag for its hepatic endpoints, its dose ladder, and…

225 questions
asked by dana_wexler 11k · 2.3 years ago
18 votes0 answers13k views
How does retatrutide at 12 mg weekly compare on cost per milligram across routes?

Stated plainly: retatrutide · 12 mg. I have worked this out and I would like someone to find the error, because I suspect there is one. My working so far, for the…

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
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
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 ben_akintola 10k · 2.3 years ago
23 votes0 answers35k views
How do I get 8 units out of a vial reconstituted to 3.33 mg/mL without guessing?

What I am working with: 8 units · 3.33 mg/mL. This is a procedural question rather than a theoretical one, and I would like the procedure rather than the theory. What…

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
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 rukhsana_iqbal 17k · 2.3 years ago
20 votes0 answers19k views
Is LDL-C worth drawing at baseline before starting a GLP-1 receptor agonist?

Setup, so nobody has to ask: LDL-C · a GLP-1 receptor agonist. I would like to set this up properly once, rather than adjust it repeatedly. My budget is real but not…

bloodwork
bloodwork

Laboratory monitoring: which panels are worth ordering, sensible intervals, reference-range versus optimal-range arguments, and how to read a…

296 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
a1c
a1c

Glycated haemoglobin as a ninety-day glycaemic average: what a change of half a point means, why it lags, and the conditions under which it…

122 questions
lipids
lipids

Lipid response on treatment: triglycerides, LDL-C, non-HDL-C, ApoB and Lp(a), which of them move with weight loss, and why a fasting panel drawn…

139 questions
asked by thermal_mass 13k · 2.3 years ago
34 votes0 answers29k views
Is ESSENCE a fair comparison of a GLP-1 receptor agonist against its comparator arm?

Setup, so nobody has to ask: ESSENCE · a GLP-1 receptor agonist. This is asserted often enough that I assumed it was established, and then I went looking for the…

clinical-trials
clinical-trials

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

745 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
tirzepatide
tirzepatide

A dual GIP and GLP-1 receptor agonist. Questions here cover the SURPASS and SURMOUNT programmes, the practical differences from a pure GLP-1…

370 questions
asked by shear_at_the_front 17k · 2.3 years ago
34 votes0 answers46k views
Does headache at week six of dulaglutide usually resolve without a dose change?

Concretely: headache · six · dulaglutide. I am trying to do this correctly the first time rather than learn it by getting it wrong. I have already made one mistake…

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
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
dulaglutide
dulaglutide

A once-weekly GLP-1 receptor agonist built on an Fc fusion rather than fatty-acid acylation. Use this tag for questions about the fusion-protein…

200 questions
asked by carys_meredith 12k · 2.3 years ago
25 votes0 answers33k views
Does headache at week six of orforglipron usually resolve without a dose change?

The particulars: headache · six · orforglipron. I am trying to do this correctly the first time rather than learn it by getting it wrong. I have already made one…

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
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
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 ben_akintola 10k · 2.3 years ago
15 votes0 answers6.7k views
Does the STEP 3 population resemble anyone asking about semaglutide here?

The case in front of me: STEP 3 · semaglutide. The figures are clear enough; the question is what they mean and what they do not. I can supply the numbers if the…

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 p_mkhize 58k · 2.3 years ago
39 votes0 answers49k views
How long does a Wuxi to Finland lane usually take with tracking?

For reference: Wuxi · Finland. I have the document in front of me and I can read the numbers. What I cannot do is interpret them. I am reasonably comfortable with…

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
customs
customs

Customs handling: how declarations are assessed, why a parcel sits at a facility for a week, seizure notices, and the practical difference between…

196 questions
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
asked by cap_the_luer 14k · 2.3 years ago
21 votes0 answers22k views
Is a GL Biochem order from Shanghai likely to hold cold chain to Spain?

Setup, so nobody has to ask: GL Biochem · Shanghai · Spain. I am at the decision point and I would rather think it through than improvise. I would rather spend money…

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 loss_on_drying 40k · 2.3 years ago
41 votes0 answers65k views
What counter-ion should I expect on an MKM semaglutide lot?

What I have: MKM · 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…

acetate-content
acetate-content

Counter-ion content, most often acetate or trifluoroacetate, and why it matters: the counter-ion and residual water are part of the gross mass you…

88 questions
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
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

476 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 sinead_gaffney 28k · 2.3 years ago
27 votes0 answers36k views
How would I detect dimerisation in a mazdutide vial without sending it to PeptideMeter?

For reference: dimerisation · mazdutide · PeptideMeter. This is a procedural question rather than a theoretical one, and I would like the procedure rather than the…

vial-inspection
vial-inspection

What you can learn by looking: cake morphology, meniscus films, fibres versus stopper fragments versus true particulates, clarity after…

66 questions
peptide-stability
peptide-stability

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

908 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
mazdutide
mazdutide

A GLP-1 and glucagon receptor dual agonist developed primarily in China, with a distinct dose range and a fast-moving publication record.…

237 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 Dr_Bram_Verhoeven 84k · 2.3 years ago
23 votes0 answers31k views
What did ESSENCE actually show on fibrosis?

The clinician who ordered the panel was not concerned; I would still like to understand it. I would like help reading this properly rather than being told what…

mash
mash

Metabolic dysfunction-associated steatohepatitis: histological endpoints, resolution without worsening fibrosis, fibrosis improvement by stage,…

56 questions
clinical-trials
clinical-trials

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

745 questions
liver-enzymes
liver-enzymes

ALT, AST, GGT and ALP: what they do and do not indicate about hepatic fat, why enzymes are a poor surrogate for histology, and where non-invasive…

91 questions
asked by cake_collapsed 14k · 2.3 years ago
31 votes0 answers22k views
Is 98.2% a realistic purity ceiling for a GLP-1 receptor agonist given its chain length?

Stated plainly: 98.2% · a GLP-1 receptor agonist. I have worked this out and I would like someone to find the error, because I suspect there is one. My working so…

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
hplc
hplc

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

503 questions
peptide-mapping
peptide-mapping

Enzymatic digestion followed by LC-MS/MS to confirm sequence rather than just mass. The method that catches a scrambled sequence or a D-amino-acid…

103 questions
asked by otto_brenner 12k · 2.3 years ago
27 votes0 answers27k views
What is the reported incidence of nausea on tirzepatide in SURMOUNT-2?

The case in front of me: nausea · tirzepatide · SURMOUNT-2. The figures are clear enough; the question is what they mean and what they do not. I can supply the…

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
clinical-trials
clinical-trials

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

745 questions
tirzepatide
tirzepatide

A dual GIP and GLP-1 receptor agonist. Questions here cover the SURPASS and SURMOUNT programmes, the practical differences from a pure GLP-1…

370 questions
asked by pk_curve 30k · 2.3 years ago
11 votes0 answers14k views
Does hair thinning at week ten of survodutide usually resolve without a dose change?

The particulars: hair thinning · ten · survodutide. Everything I have found on this is either a forum aside or a product page, neither of which I trust. I am…

hair-loss
hair-loss

Telogen effluvium following rapid weight loss versus a drug-attributable effect: the timing signature that distinguishes them, protein and…

50 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
survodutide
survodutide

A GLP-1 and glucagon receptor dual agonist with a substantial published MASH dataset. Use this tag for its hepatic endpoints, its dose ladder, and…

225 questions
asked by pieter_maas 14k · 2.3 years ago
30 votes0 answers35k views
Has anyone independently verified an SWB retatrutide batch COA?

The particulars: SWB · retatrutide. I am asking for verification rather than opinion, ideally with something I can read myself. It is possible the evidence exists and…

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
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
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
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 ruaidhri_o_shea 25k · 2.3 years ago
31 votes0 answers48k views
Which electrolyte shortfall presents as fatigue first?

Scale weight, waist circumference and a repetition maximum, all logged weekly. I would like to know the limits of what can be inferred from this. What I am trying to…

electrolytes
electrolytes

Sodium, potassium and magnesium during reduced intake and GI losses: what the symptoms of a shortfall look like, when a panel is worth drawing,…

72 questions
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
hydration
hydration

Fluid intake when thirst and intake cues are both blunted: how much of the early scale drop is fluid, how dehydration confounds a renal panel, and…

14 questions
asked by oona_kekkonen 13k · 2.3 years ago
25 votes0 answers33k views
What has VendorInvestigate published on SSA lots in the last year?

The case in front of me: VendorInvestigate · SSA. I would like to know the limits of what can be inferred from this. What I am trying to avoid is over-reading a…

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
asked by lucia_marchetti 19k · 2.3 years ago
27 votes0 answers31k views
What does REDEFINE-1 tell me about vomiting at the 2.4 mg dose?

Concretely: REDEFINE-1 · vomiting · 2.4 mg. I would like to know the limits of what can be inferred from this. What I am trying to avoid is over-reading a single…

clinical-trials
clinical-trials

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

745 questions
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
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
asked by t_oyelaran 79k · 2.3 years ago