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Compounds · Semaglutide · continued

Semaglutide half-life: where the 165 to 184 hour figure comes from — what changed since posts 61–90

This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.

IW
i.wojcikTL2 Moderator12 Dec 2024#61

This follows post #58 rather than contradicting it.

The opalescent appearance in semaglutide solutions is occasionally noted and the mechanism is unclear. It does not appear to correlate with product failure in practice. Visible particles or frank cloudiness is different and would be reason to contact the supplier.

3 likes 20mo
BE
bench_entryTL3Regular13 Dec 2024#62
g.haaland, post #27: post #26 is right about the mechanism and I think understates the practical bit. Approved indications differ by jurisdiction and change. As of mid-2026 the weight-management indication is approved in many European jurisdictions but not all, and access is still narrower in others. For your own region, check the regulatory website rather… Go to post

Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing.

The correction was fair and I had been repeating something I had not checked carefully enough.

11 likes in reply to #27 19mo
JF
j.falkTL2 Moderator15 Dec 2024#63
se.okafor, post #48: Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing. The correction was fair and I had been repeating something I had not checked carefully enough. Go to post

The SELECT trial changed the positioning because it was the first cardiovascular outcome trial in people without diabetes. That decoupled the cardiovascular argument from glycaemic control, which is why it mattered beyond its own numbers.

33 likes in reply to #48 19mo
V
VPoulsenTL3Regular16 Dec 2024#64

Semaglutide versus liraglutide in STEP 8: semaglutide produced greater weight reduction and the discontinuation rates differed. But the trial was open-label for the dosing schedule, which admits expectation effects. Weekly versus daily itself is part of the comparison, not a confounding variable to be removed.

0 likes 19mo
FL
f.lindholmTL2 Moderator18 Dec 2024#65

Is there a ceiling dose beyond which the effect plateaus? The trials did not study that because they stopped at 2.4 mg. Some people report trying higher doses, but trial data is absent and off-label dosing enters territory this site does not advise on.

7 likes 19mo
IL
integrator_logTL3Regular19 Dec 2024#66

The 165 to 184 hour range: that is roughly 7 to 7.6 days, which is why the weekly schedule works. Below 4 half-lives you are not approaching steady state yet, which is the pharmacological argument for the four-week step interval.

17 likes 19mo
BF
b.friskTL2 Moderator21 Dec 2024#67
an.kirchner, post #58: post #57 answers the question as asked. The question underneath it is different. For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use. Go to post

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

0 likes in reply to #58 19mo
BS
buffer_sheetTL3Regular22 Dec 2024#68

On post #64 — agreed on the reasoning, with one qualification.

The C-cell question: semaglutide triggered medullary thyroid carcinoma in rodent toxicology studies. A signal in rodents does not automatically appear in humans, but it is the reason the compound is contraindicated in people with personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2.

1 like 19mo
DV
d.vestergaardTL2 Moderator24 Dec 2024#69
h.bakker, post #1: Posting this under the heading it deserves: Semaglutide half-life: where the 165 to 184 hour figure comes from — what changed since Everything below is what sits behind that. Comparing STEP 8 ( JAMA , 2022) with STEP 4 ( JAMA , 2021) and finding the comparison harder than it looks. Different populations, different durations, different… Go to post

Albumin binding is not a unique structural feature and nothing in the class lacks it, but the reversibility matters. Semaglutide binds albumin covalently through a fatty side chain, which creates a very long half-life at the cost of sequestering the free form. That is a trade-off and it is the trade-off that allows weekly dosing.

0 likes in reply to #1 19mo
D
DOdendaalTL3Regular25 Dec 2024#70
p.onwuka, post #16: This follows post #13 rather than contradicting it. The STEP programme populations were selected: enrollment criteria required baseline body mass index over 30, no recent blood pressure crisis, no recent retinopathy, no renal disease at the time. Applying results from that population to someone well outside it is an extrapolation and… Go to post

The mass figure differs between sources because of how the different entities report it. The monoisotopic mass of the bare peptide is one number; the mass including the acylation is another. Different sources emphasise different details.

4 likes in reply to #16 19mo
BB
b.brandtTL2 Moderator26 Dec 2024#71
a.teixeira, post #7: This follows post #4 rather than contradicting it. Approved indications differ by jurisdiction and change. As of mid-2026 the weight-management indication is approved in many European jurisdictions but not all, and access is still narrower in others. For your own region, check the regulatory website rather than a forum summary. Go to post

Worth separating two things that post #67 runs together.

Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing.

The correction was fair and I had been repeating something I had not checked carefully enough.

1 like in reply to #7 19mo
DM
d.magalhesTL2Member28 Dec 2024#72

post #71 is right about the mechanism and I think understates the practical bit.

The STEP programme populations were selected: enrollment criteria required baseline body mass index over 30, no recent blood pressure crisis, no recent retinopathy, no renal disease at the time. Applying results from that population to someone well outside it is an extrapolation and should be called one.

0 likes 19mo
RM
ra.mensaTL2 Moderator29 Dec 2024#73

Gastric emptying delay is the mechanism behind most of the gastrointestinal side effects. Slowing the stomach empties it feeds less food into the intestines at a time, which is part of the satiety mechanism but is also why nausea is dose-dependent and titration-dependent.

16 likes 19mo
M
MSaarinenTL3Regular31 Dec 2024#74

On alcohol: the labelling does not contraindicate it, but it raises gastric irritation risk and semaglutide already does that. There is no published interaction study and the conservative position is to limit it if you are titrating or if gastrointestinal symptoms are troublesome.

6 likes 19mo
AM
a.molnarTL2 Moderator1 Jan 2025#75

Approved indications differ by jurisdiction and change. As of mid-2026 the weight-management indication is approved in many European jurisdictions but not all, and access is still narrower in others. For your own region, check the regulatory website rather than a forum summary.

0 likes 19mo
D
DSakamotoTL3Regular3 Jan 2025#76

post #75 answers the question as asked. The question underneath it is different.

Approved indications differ by jurisdiction and change. As of mid-2026 the weight-management indication is approved in many European jurisdictions but not all, and access is still narrower in others. For your own region, check the regulatory website rather than a forum summary.

32 likes 19mo
AW
am.wikstromTL2 Moderator4 Jan 2025 · edited#77

Coming back to post #75, because the follow-up matters more than the original answer.

The 165 to 184 hour range: that is roughly 7 to 7.6 days, which is why the weekly schedule works. Below 4 half-lives you are not approaching steady state yet, which is the pharmacological argument for the four-week step interval.

11 likes 19mo
I
IbrahimoviTL2Member6 Jan 2025#78
p.onwuka, post #16: This follows post #13 rather than contradicting it. The STEP programme populations were selected: enrollment criteria required baseline body mass index over 30, no recent blood pressure crisis, no recent retinopathy, no renal disease at the time. Applying results from that population to someone well outside it is an extrapolation and… Go to post

Is there a ceiling dose beyond which the effect plateaus? The trials did not study that because they stopped at 2.4 mg. Some people report trying higher doses, but trial data is absent and off-label dosing enters territory this site does not advise on.

3 likes in reply to #16 19mo
RR
r.restrepoTL2 Moderator7 Jan 2025#79
m.yilmaz, post #24: The SELECT trial changed the positioning because it was the first cardiovascular outcome trial in people without diabetes. That decoupled the cardiovascular argument from glycaemic control, which is why it mattered beyond its own numbers. Go to post

Semaglutide versus liraglutide in STEP 8: semaglutide produced greater weight reduction and the discontinuation rates differed. But the trial was open-label for the dosing schedule, which admits expectation effects. Weekly versus daily itself is part of the comparison, not a confounding variable to be removed.

6 likes in reply to #24 19mo
ML
m.lindqvistTL2 Moderator8 Jan 2025#80
resistance_first, post #6: Worth separating two things that post #2 runs together. The 165 to 184 hour range: that is roughly 7 to 7.6 days, which is why the weekly schedule works. Below 4 half-lives you are not approaching steady state yet, which is the pharmacological argument for the four-week step interval. Go to post

The SELECT trial changed the positioning because it was the first cardiovascular outcome trial in people without diabetes. That decoupled the cardiovascular argument from glycaemic control, which is why it mattered beyond its own numbers.

1 like in reply to #6 19mo
SL
s.leclercTL4 Moderator10 Jan 2025#81
cannula_trace, post #43: For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use. Go to post
Staff post. Actions described here are recorded in the public moderation log and may be challenged in Meta.

The opalescent appearance in semaglutide solutions is occasionally noted and the mechanism is unclear. It does not appear to correlate with product failure in practice. Visible particles or frank cloudiness is different and would be reason to contact the supplier.

16 likes in reply to #43 19mo
MI
m.ibarraTL2 Moderator11 Jan 2025#82

On alcohol: the labelling does not contraindicate it, but it raises gastric irritation risk and semaglutide already does that. There is no published interaction study and the conservative position is to limit it if you are titrating or if gastrointestinal symptoms are troublesome.

32 likes 19mo
MH
ms_hollowayTL4Mass spectrometrist13 Jan 2025#83

This follows post #80 rather than contradicting it.

The C-cell question: semaglutide triggered medullary thyroid carcinoma in rodent toxicology studies. A signal in rodents does not automatically appear in humans, but it is the reason the compound is contraindicated in people with personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2.

0 likes 18mo
YA
y.adebayoTL2 Moderator14 Jan 2025#84

I read post #82 twice before replying, because I had assumed the opposite.

Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing.

The correction was fair and I had been repeating something I had not checked carefully enough.

3 likes 18mo
EF
endo_fellow_rkTL3Endocrinology fellow16 Jan 2025#85
n.okwuosa, post #36: post #35 is right about the mechanism and I think understates the practical bit. Approved indications differ by jurisdiction and change. As of mid-2026 the weight-management indication is approved in many European jurisdictions but not all, and access is still narrower in others. For your own region, check the regulatory website rather… Go to post

post #84 answers the question as asked. The question underneath it is different.

Albumin binding is not a unique structural feature and nothing in the class lacks it, but the reversibility matters. Semaglutide binds albumin covalently through a fatty side chain, which creates a very long half-life at the cost of sequestering the free form. That is a trade-off and it is the trade-off that allows weekly dosing.

11 likes in reply to #36 18mo
RE
r.ekstromTL2 Moderator17 Jan 2025#86
z.adeyemi, post #56: Albumin binding is not a unique structural feature and nothing in the class lacks it, but the reversibility matters. Semaglutide binds albumin covalently through a fatty side chain, which creates a very long half-life at the cost of sequestering the free form. That is a trade-off and it is the trade-off that allows weekly dosing. Go to post

The mass figure differs between sources because of how the different entities report it. The monoisotopic mass of the bare peptide is one number; the mass including the acylation is another. Different sources emphasise different details.

24 likes in reply to #56 18mo
TH
TL4_HalvorsenTL4Leader · Journal club18 Jan 2025 · edited#87

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

0 likes 18mo
CA
c.amankwahTL2 Moderator20 Jan 2025#88

Coming back to post #86, because the follow-up matters more than the original answer.

Gastric emptying delay is the mechanism behind most of the gastrointestinal side effects. Slowing the stomach empties it feeds less food into the intestines at a time, which is part of the satiety mechanism but is also why nausea is dose-dependent and titration-dependent.

1 like 18mo
SB
s.bergstromTL2 Moderator21 Jan 2025#89

post #88 is right about the mechanism and I think understates the practical bit.

The STEP programme populations were selected: enrollment criteria required baseline body mass index over 30, no recent blood pressure crisis, no recent retinopathy, no renal disease at the time. Applying results from that population to someone well outside it is an extrapolation and should be called one.

30 likes 18mo
TN
t.ndiayeTL2 Moderator22 Jan 2025#90
r.ekstrom, post #86: The mass figure differs between sources because of how the different entities report it. The monoisotopic mass of the bare peptide is one number; the mass including the acylation is another. Different sources emphasise different details. Go to post

Worth separating two things that post #86 runs together.

Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing.

The correction was fair and I had been repeating something I had not checked carefully enough.

0 likes in reply to #86 18mo