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Newest first. 5.2k questions across 107 tags.

5.2k questions · page 105 of 217

2 votes5 answers13k views
Does positional apnoea respond differently to weight loss?

The clinician who ordered the panel was not concerned; I would still like to understand it. I want to know whether this is a real physical effect or an artefact of…

sleep-apnea
sleep-apnea

Obstructive sleep apnoea and the apnoea-hypopnoea index response to weight loss, including the SURMOUNT-OSA dataset and the question of whether…

6 questions
clinical-trials
clinical-trials

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

745 questions
weight-regain
weight-regain

Regain after stopping or reducing: the trajectory reported in the withdrawal extensions, how much is fluid, and what the maintenance arms tell us…

10 questions
asked by noor_alhassan 11k · 14 months ago
17 votes 5 answers12k views
Does oxidation of oral semaglutide at minus 80 °C show up as a loss of content or of purity?

Concretely: oxidation · oral semaglutide · minus 80 °C. I want to know whether this is a real physical effect or an artefact of how it is measured. What prompted the…

peptide-stability
peptide-stability

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

908 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
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
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_Aoife_Brennan 20k · 14 months ago
15 votes0 answers8.9k views
How long does survodutide stay within specification at 4 °C once reconstituted?

The case in front of me: survodutide · 4 °C. I have done this once and I suspect I got away with it rather than got it right. For context: I keep records of every…

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
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 per_haugen 13k · 14 months ago
23 votes 5 answers32k views
Does the TRIUMPH-1 population resemble anyone asking about retatrutide here?

Concretely: TRIUMPH-1 · retatrutide. 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 result,…

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
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 dana_wexler 11k · 14 months ago
13 votes 2 answers11k views
Why did my HbA1c move after twelve weeks on dulaglutide?

The case in front of me: HbA1c · twelve weeks · dulaglutide. I have two candidate explanations and no way to distinguish them. The same procedure has worked without…

bloodwork
bloodwork

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

296 questions
kidney-function
kidney-function

eGFR, creatinine, cystatin C and albuminuria: the acute haemodynamic dip that is not injury, the renal outcome data from the FLOW programme, and…

141 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
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
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 marta_szymanska 10k · 14 months ago
19 votes 5 answers12k views
How much protein in grams do I need at 81 kg on 900 kcal a day?

The case in front of me: 81 kg · 900 kcal. Please show the division. I want to check my own against yours. I would like the general form as well as the specific…

protein-intake
protein-intake

Protein targets in grams per kilogram, per-meal distribution and the leucine threshold, and the evidence for a higher intake specifically during…

60 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
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
asked by ivo_paunovic 16k · 14 months ago
14 votes0 answers6.2k views
Is fatigue on semaglutide dose-dependent or dose-rate dependent?

What I have: fatigue · semaglutide. I would like the mechanism, because I want to be able to reason about the cases nobody has written about. I have tried to reason…

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
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 sian_llewellyn 65k · 14 months ago
32 votes5 answers29k views
Would you re-test liraglutide after ten weeks at minus 80 °C, or accept the original certificate?

The particulars: liraglutide · ten weeks · minus 80 °C. I would like to define my thresholds before I have a result, for obvious reasons. I want a plan with explicit…

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
peptide-stability
peptide-stability

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

908 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
liraglutide
liraglutide

A once-daily GLP-1 receptor agonist and the compound that established the class. Still relevant for its shorter half-life, its paediatric and…

235 questions
asked by klara_novotna 19k · 14 months ago
35 votes 5 answers31k views
Is 15 mg in 1.5 mL of phosphate-buffered diluent a sensible presentation for dulaglutide?

For reference: 15 mg · 1.5 mL · phosphate-buffered diluent · dulaglutide. I would like to define my thresholds before I have a result, for obvious reasons. I want a…

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
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 bea_castellanos 24k · 14 months ago
20 votes 5 answers20k views
What counter-ion should I expect on a GL Biochem ecnoglutide lot?

The case in front of me: GL Biochem · ecnoglutide. I want to understand what this actually establishes, as opposed to what it is being used to imply. My concern is…

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
ecnoglutide
ecnoglutide

A long-acting GLP-1 receptor agonist with a cAMP-biased signalling profile. A niche tag, mostly used for mechanism questions about biased agonism…

223 questions
asked by cake_intact 17k · 14 months ago
20 votes 5 answers9.4k views
Does triglycerides tell me anything about hepatic fat on survodutide?

Details up front: triglycerides · survodutide. I would like the mechanism, because I want to be able to reason about the cases nobody has written about. I have tried…

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
mash
mash

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

56 questions
bloodwork
bloodwork

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

296 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
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 label_claim 30k · 14 months ago
26 votes5 answers25k views
How do I convert the STEP 2 hazard ratio into an absolute risk reduction?

I have the full paper rather than the abstract, and the supplementary appendix. I would rather understand the derivation than memorise the outcome. Two people I asked…

cardiovascular
cardiovascular

Cardiovascular outcomes: the SELECT major-adverse-event result, SOUL, SUSTAIN 6 and REWIND, how to convert a hazard ratio into an absolute risk…

68 questions
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
asked by teodora_ilic 17k · 14 months ago
17 votes 5 answers17k views
Does LDL-C tell me anything about hepatic fat on mazdutide?

The particulars: LDL-C · mazdutide. I keep seeing this stated as a fact with no explanation attached, and unexplained facts make me suspicious. My background is…

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
mash
mash

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

56 questions
bloodwork
bloodwork

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

296 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
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
asked by j_wierzbicki 69k · 14 months ago
27 votes 3 answers9.9k views
How many draws do I need before a lab trend means anything? My ALT went 24 to 41

Baseline ALT was 24 U/L. Fourteen weeks into semaglutide it came back at 41 U/L, still inside the lab's quoted range of 0 to 50 but a 71% rise from where I started. I…

bloodwork
bloodwork

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

296 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
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_Signe_Baldursdottir 29k · 14 months ago
25 votes 5 answers28k views
What temperature does a domestic freezer actually hold?

This is a recurring problem with one particular shipping lane rather than a one-off. I would like help reading this properly rather than being told what conclusion to…

storage
storage

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

701 questions
freeze-thaw
freeze-thaw

What repeated freezing does to a peptide in solution: ice-crystal shear at the growing front, freeze-concentration of solutes, pH shifts as buffer…

57 questions
peptide-stability
peptide-stability

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

908 questions
asked by ahmed_zerouali 15k · 14 months ago
4 votes 5 answers9k views
Why did my creatinine move after two weeks on survodutide?

Conditions: creatinine · two weeks · survodutide. This is not behaving the way I expected and I want to understand the discrepancy before I act on it. I have…

bloodwork
bloodwork

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

296 questions
kidney-function
kidney-function

eGFR, creatinine, cystatin C and albuminuria: the acute haemodynamic dip that is not injury, the renal outcome data from the FLOW programme, and…

141 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
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 deamidation_watch 45k · 14 months ago
34 votes 5 answers15k views
How many vial-days does a 20 mg vial give at 8 mg/mL on a weekly schedule?

Stated plainly: 20 mg · 8 mg/mL. 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 record,…

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 hana_petrikova 10k · 14 months ago
29 votes 5 answers21k views
Has anyone independently verified a WXT a GLP-1 receptor agonist batch COA?

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

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
asked by sunniva_dahl 22k · 14 months ago
19 votes 5 answers15k views
Does splitting a 2.4 mg weekly dose of cagrilintide across two administrations change anything?

Stated plainly: 2.4 mg · cagrilintide. I keep seeing this stated as a fact with no explanation attached, and unexplained facts make me suspicious. My background is…

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
amylin
amylin

Amylin and its analogues, most prominently cagrilintide, as a satiety mechanism orthogonal to incretin signalling. Includes the pharmacology of…

237 questions
asked by tri_gly_ala 24k · 14 months ago
19 votes 5 answers21k views
What does "identity confirmed" mean without a quantified content figure?

I am comparing a supplier certificate against an independent result on the same lot. I would like help reading this properly rather than being told what conclusion to…

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
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
mass-spec
mass-spec

Mass spectrometry for identity confirmation: electrospray ionisation, multiple charge states, monoisotopic versus average mass, deconvolution, and…

52 questions
asked by dermot_kiely 12k · 14 months ago
4 votes5 answers13k views
How long does a Chengdu to the United States lane usually take with tracking?

Details up front: Chengdu · the United States. I would like help reading this properly rather than being told what conclusion to reach. I have the full report…

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 p_mkhize 58k · 14 months ago
17 votes 2 answers12k views
What does the mechanism of tirzepatide predict that SURMOUNT-3 did not test?

Setup, so nobody has to ask: tirzepatide · SURMOUNT-3. I keep seeing this stated as a fact with no explanation attached, and unexplained facts make me suspicious. My…

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
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 two_point_four 8.9k · 14 months ago
31 votes 3 answers13k views
DEXA vs BIA vs BodPod: which of these is actually telling me the truth about lean mass?

I have measured myself three ways inside eight days and got three different stories, and I would like to understand which one to believe before I change anything…

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
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
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 eoin_mcgarry 18k · 14 months ago
24 votes0 answers17k views
Is 96.4% a realistic purity ceiling for orforglipron given its chain length?

Details up front: 96.4% · orforglipron. I can do the algebra. I am not confident about the conversion factors. If there is a standard way to lay this out, I would…

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
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 assay_blank 45k · 14 months ago