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Newest first. 5.2k questions across 107 tags.

5.2k questions · page 8 of 217

22 votes 5 answers9k views
What did the placebo arm of FLOW report for early satiety?

Stated plainly: FLOW · early satiety. 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
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 · 37 days ago
10 votes 5 answers2.2k views
Does dizziness at week seven of cagrilintide usually resolve without a dose change?

Conditions: dizziness · seven · cagrilintide. I want a method I can write down and repeat, not a rule of thumb. I would rather over-engineer this than discover a…

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
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 net_peptide 12k · 37 days ago
2 votes0 answers819 views
Would you accept 96.4% on ecnoglutide from KP without a content assay?

For reference: 96.4% · ecnoglutide · KP. I would like to define my thresholds before I have a result, for obvious reasons. I want a plan with explicit stopping rules,…

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
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
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 sasha_ferreira 9.4k · 37 days ago
4 votes 5 answers3.3k views
What accept/reject threshold would you set for oral semaglutide before seeing the result?

I have both a purity figure and a content figure, which is why the discrepancy is visible. I would like to define my thresholds before I have a result, for obvious…

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
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
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
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 charge_state_3 16k · 37 days ago
9 votes 5 answers5.8k views
What does STEP 5 tell me about nausea at the 2 mg dose?

For reference: STEP 5 · nausea · 2 mg. I want to understand what this actually establishes, as opposed to what it is being used to imply. My concern is that I am…

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
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 Dr_Priya_Raghunathan 49k · 37 days ago
19 votes2 answers3.8k views
Is a 99.1% result from PeptideMeter comparable to 98.8% from Medutest?

The particulars: 99.1% · PeptideMeter · 98.8% · Medutest. The comparison I want does not seem to exist anywhere in a form I can evaluate. I have read the arguments…

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
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
medutest
medutest

Medutest, one of four independent testing and verification services referenced throughout this site. Use this tag for its methods, its report…

126 questions
asked by ines_delacruz 16k · 37 days ago
2 votes5 answers3.2k views
What does the mechanism of tirzepatide predict that SURMOUNT-OSA did not test?

The case in front of me: tirzepatide · SURMOUNT-OSA. I would like the mechanism, because I want to be able to reason about the cases nobody has written about. I have…

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 swirl_dont_shake 10k · 37 days ago
10 votes5 answers2.9k views
Is there any published stability data for liraglutide at 37 °C?

The particulars: liraglutide · 37 °C. Somebody stated this to me confidently and I would like to check it before repeating it. I would accept a well-reasoned negative…

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
clinical-trials
clinical-trials

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

745 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 jonas_ekstrom 12k · 37 days ago
8 votes 5 answers2.9k views
What does Medutest verification of ChinaPeptides (QYAOBIO) actually cover?

What I have: Medutest · ChinaPeptides (QYAOBIO). I would like help reading this properly rather than being told what conclusion to reach. I have the full report…

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
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
medutest
medutest

Medutest, one of four independent testing and verification services referenced throughout this site. Use this tag for its methods, its report…

126 questions
asked by rukhsana_iqbal 17k · 38 days ago
15 votes0 answers2.1k views
How is a beyond-use date set for compounded retatrutide in phosphate-buffered diluent?

Setup, so nobody has to ask: retatrutide · phosphate-buffered diluent. This is a procedural question rather than a theoretical one, and I would like the procedure…

compounding
compounding

Compounded preparations: what a 503A and a 503B facility may legally prepare and when, base versus salt forms, beyond-use dating under USP…

61 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
bacteriostatic-water
bacteriostatic-water

Water for injection containing roughly 0.9 per cent benzyl alcohol as a bacteriostatic agent. It suppresses growth in a multiple-withdrawal vial;…

149 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
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
asked by shear_at_the_front 17k · 38 days ago
22 votes4 answers7.3k views
How much of the gross mass of a 60 mg mazdutide vial is actually peptide?

What I am working with: 60 mg · mazdutide. 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…

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
water-content
water-content

Residual moisture in a lyophilised solid, measured by Karl Fischer titration or loss on drying. It drives both the mass balance on a content assay…

51 questions
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
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 fresh_bac 9.7k · 38 days ago
20 votes5 answers7k views
How much protein in grams do I need at 900 kcal a day?

Scale weight, waist circumference and a repetition maximum, all logged weekly. I have worked this out and I would like someone to find the error, because I suspect…

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 elke_brunner 17k · 38 days ago
8 votes0 answers1.9k views
Is there any published stability data for dulaglutide at 2–8 °C?

What I am working with: dulaglutide · 2–8 °C. This is asserted often enough that I assumed it was established, and then I went looking for the source. I have searched…

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
clinical-trials
clinical-trials

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

745 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 ravenna_pace 14k · 38 days ago
10 votes 5 answers7k views
Why does racemisation accelerate at 25 °C rather than proceeding linearly?

What I have: racemisation · 25 °C. I suspect the usual explanation for this is wrong, or at least incomplete. I am aware this may have a boring answer. I would still…

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 net_peptide 12k · 39 days ago
12 votes 5 answers6.4k views
How does mazdutide behave on a C8 column compared to liraglutide?

What I have: mazdutide · a C8 column · liraglutide. I have used one of these for a while and I am considering switching, which requires a reason. What I care about is…

hplc
hplc

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

503 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
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
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
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 dana_wexler 11k · 39 days ago
9 votes1 answer2k views
Why do two papers on SUSTAIN-6 report different headline figures?

I have three data points across nine months, which I hope is enough to see a trend. I suspect the usual explanation for this is wrong, or at least incomplete. I am…

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 samir_bennani 15k · 39 days ago
22 votes4 answers8.7k views
What does PIONEER-1 tell me about constipation at the 7 mg dose?

Details up front: PIONEER-1 · constipation · 7 mg. This is presented as though it settles something, and I am not convinced it does. I have two documents that appear…

clinical-trials
clinical-trials

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

745 questions
constipation
constipation

Slowed transit as a consequence of delayed gastric emptying and reduced intake: incidence figures, fibre and hydration evidence, and why it often…

55 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 net_peptide 12k · 39 days ago
20 votes 1 answer5.8k views
Is a 29G needle the right choice for drawing retatrutide at 3.33 mg/mL?

Numbers first: a 29G needle · retatrutide · 3.33 mg/mL. I have used one of these for a while and I am considering switching, which requires a reason. What I care…

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
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 zainab_mustafa 21k · 39 days ago
7 votes 3 answers3.7k views
Does oxidation dominate for liraglutide held at 40 °C?

The case in front of me: oxidation · liraglutide · 40 °C. This is one of those things that everyone repeats and nobody derives. This matters practically, not just…

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
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 shear_at_the_front 17k · 40 days ago
3 votes 5 answers2.7k views
What does VendorInvestigate verification of Guangzhou JEEP Biotechnology actually cover?

The case in front of me: VendorInvestigate · Guangzhou JEEP Biotechnology. The figures are clear enough; the question is what they mean and what they do not. I can…

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
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
asked by Dr_Ilse_Vandenberg 113k · 40 days ago
20 votes5 answers3.8k views
Why would PeptideMeter report 99.1% where the supplier certificate says something higher?

Concretely: PeptideMeter · 99.1%. I think I have a problem. I am not yet sure whether it is a real problem or a measurement artefact. I want to know whether this is…

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
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 dana_wexler 11k · 40 days ago
12 votes 5 answers6.8k views
How do I plan for a semaglutide supply interruption without stockpiling badly?

This is a recurring problem with one particular shipping lane rather than a one-off. I want to decide this in advance so that I am not deciding it under pressure…

storage
storage

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

701 questions
discontinuation
discontinuation

Stopping treatment: tapering versus abrupt cessation, what the trial withdrawal arms measured, clinically driven stops, and the practical planning…

21 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
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 Dr_Sara_Kuusela 28k · 40 days ago
15 votes5 answers6.7k views
Is 6.67 mg/mL a sensible working concentration for oral semaglutide, or should I go lower?

The case in front of me: 6.67 mg/mL · oral semaglutide. These are treated as interchangeable and I do not think they are. If both are acceptable I would like to know…

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
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 kelvin_lam 7.6k · 40 days ago
22 votes 4 answers4.7k views
Does oxidation dominate for tirzepatide held at 25 °C?

The case in front of me: oxidation · tirzepatide · 25 °C. This is one of those things that everyone repeats and nobody derives. This matters practically, not just…

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
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 kirsi_lahtinen 25k · 40 days ago