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Compounds · Tirzepatide · continued

Tirzepatide in type 2 diabetes: the SURPASS programme, summarised honestly — the long version posts 31–60

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

HK
h.krastevTL24 Dec 2025#31
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DKwiatkowskiTL3Regular4 Dec 2025#32
s.chowdhury, post #1: On the subject in the title: Tirzepatide in type 2 diabetes: the SURPASS programme, summarised honestly — the long version Working notes rather than a conclusion. Session topic: PIONEER 6 ( N Engl J Med , 2019). Please read it before posting; the discussion is much better when everyone has. The question I would like us to start with is… Go to post

This follows post #29 rather than contradicting it.

SURMOUNT-1 reported weight reduction of a magnitude that was the largest for a pharmacological intervention at that time of publication. It also reported a clear dose response across three doses. The categorical thresholds (people reaching 10%, 15%, 20% loss) got the most attention but read less informatively than the mean weight change.

0 likes in reply to #1 8mo
DA
d.achebeTL2 Moderator4 Dec 2025#33

Titration schedules for tirzepatide have more dose steps than semaglutide partly because the compound is more potent and partly because the clinical programme used a finer gradation. That does not mean you cannot escalate on a coarser schedule if that suits you — the published schedule is not a lower bound.

26 likes 8mo
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NorringtonTL3Regular5 Dec 2025#34

I disagree with the reply above, and I think the disagreement is substantive rather than terminological.

The distinction being drawn does not survive when you look at the published data for this specific question. I would be glad to be shown wrong on this, because the version I am arguing against is more convenient.

12 likes 8mo
AM
a.molnarTL2 Moderator5 Dec 2025 · edited#35

Dual agonism versus dose: how much of tirzepatide's effect is the GIP component and how much is simply achieving higher receptor engagement? The honest answer is that the question is not settled. Some of the effect is surely the GIP component, but the trial design does not decompose it.

4 likes 8mo
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DSakamotoTL3Regular5 Dec 2025#36
DKwiatkowski, post #32: This follows post #29 rather than contradicting it. SURMOUNT-1 reported weight reduction of a magnitude that was the largest for a pharmacological intervention at that time of publication. It also reported a clear dose response across three doses. The categorical thresholds (people reaching 10%, 15%, 20% loss) got the most attention but… Go to post

Picking up post #33: that is the part I would want checked first.

SURMOUNT-OSA is notable because it used an objective physiological endpoint, the apnoea-hypopnoea index, rather than a symptom scale. Two parallel trials, with and without positive airway pressure, addressed the confounder directly. The reduction was substantial in both.

0 likes in reply to #32 8mo
CK
c.kuuselaTL2 Moderator5 Dec 2025#37

Two things before anyone answers the substance.

First, the context in the first post is clear and specific. Second, the question is framed so that an answer can actually address it. Both are the norm here and both matter more than they sound.

0 likes 8mo
TF
taper_fileTL3Regular5 Dec 2025#38

SURMOUNT-4 used a randomised withdrawal design: everyone titrated, then those on maintenance were randomised to continue or placebo. Continuation maintained effect; withdrawal was followed by regain. The finding is robust but it says nothing about a lower effective maintenance dose, because that was not studied.

18 likes 8mo
RW
r.weissTL2 Moderator5 Dec 2025#39

Nausea profile: some people report tirzepatide as less nausea-prone than semaglutide, others report it as more. The trial reported gastrointestinal effects broadly comparable in character. Individual variation is the largest factor.

7 likes 8mo
IA
i.aranda_esTL2Translator · ES6 Dec 2025#40

I disagree with the reply above, and I think the disagreement is substantive rather than terminological.

The distinction being drawn does not survive when you look at the published data for this specific question. I would be glad to be shown wrong on this, because the version I am arguing against is more convenient.

1 like 8mo
IB
i.balogunTL2 Moderator6 Dec 2025 · edited#41

The 2.5 mg starting dose is not a therapeutic dose in the sense that weight loss is minimal at that dose. It is a tolerance-testing dose. Confusing the purpose of a starting dose with the purpose of a maintenance dose leads to false conclusions about efficacy.

4 likes 8mo
JR
j.rasmussenTL2Regular6 Dec 2025#42

The GIP component: GIP receptor agonism is thought to amplify the GLP-1 effect on satiety and energy expenditure, but how much of tirzepatide's effect is that and how much is simply achieving higher receptor occupancy remains genuinely open. The mechanistic literature is active.

11 likes 8mo
CC
c.chowdhuryTL2 Moderator6 Dec 2025#43

post #42 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.

33 likes 8mo
TY
two_year_lineTL3Regular6 Dec 2025#44
dr_seong, post #23: Picking up post #20: that is the part I would want checked first. SURMOUNT-1 reported weight reduction of a magnitude that was the largest for a pharmacological intervention at that time of publication. It also reported a clear dose response across three doses. The categorical thresholds (people reaching 10%, 15%, 20% loss) got the most… Go to post

On post #40 — agreed on the reasoning, with one qualification.

Storage and stability: published data on licensed tirzepatide formulations exists and is worth reading directly rather than through summarised claims. Reconstituted preparations in different diluents have not been studied and extrapolation from the licensed formulation is the best you can do.

0 likes in reply to #23 8mo
JS
j.sandvikTL2 Moderator6 Dec 2025#45

Half-life difference: tirzepatide is about 5 days versus semaglutide's week-long. Practically, that means steady state is reached slightly faster and the post-dose swing is slightly larger. Most people do not report noticing the difference in practical terms.

1 like 8mo
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FConsidineTL1Member6 Dec 2025#46

I read post #44 twice before replying, because I had assumed the opposite.

Dual agonism versus dose: how much of tirzepatide's effect is the GIP component and how much is simply achieving higher receptor engagement? The honest answer is that the question is not settled. Some of the effect is surely the GIP component, but the trial design does not decompose it.

7 likes 8mo
YA
y.adeyemiTL2 Moderator7 Dec 2025#47

post #46 is right about the mechanism and I think understates the practical bit.

Titration schedules for tirzepatide have more dose steps than semaglutide partly because the compound is more potent and partly because the clinical programme used a finer gradation. That does not mean you cannot escalate on a coarser schedule if that suits you — the published schedule is not a lower bound.

25 likes 8mo
AT
a.thorneTL2Wiki editor7 Dec 2025#48
m.lehtinen, post #30: On post #26 — agreed on the reasoning, with one qualification. SURPASS-2 compared tirzepatide with semaglutide 1.0 mg, the licensed diabetes dose at that time. It did not compare with semaglutide 2.4 mg, the highest approved dose. That is the central and legitimate criticism of the head-to-head evidence and it is worth remembering when… Go to post

Two things before anyone answers the substance.

First, the context in the first post is clear and specific. Second, the question is framed so that an answer can actually address it. Both are the norm here and both matter more than they sound.

0 likes in reply to #30 8mo
IN
i.norgaardTL2 Moderator7 Dec 2025#49

Picking up post #46: that is the part I would want checked first.

SURMOUNT-1 reported weight reduction of a magnitude that was the largest for a pharmacological intervention at that time of publication. It also reported a clear dose response across three doses. The categorical thresholds (people reaching 10%, 15%, 20% loss) got the most attention but read less informatively than the mean weight change.

11 likes 8mo
IT
impurity_tableTL3Analytical chemist7 Dec 2025#50

Mass and charge states: tirzepatide is about 4813.5 Da and on an electrospray instrument you would expect to see charge states mostly in the 2+ to 4+ range, the same as semaglutide. A doubly charged species would appear at about (4813.5 + 2 × 1.008) / 2 ≈ 2408.

24 likes 8mo
TT
t.tullochTL2 Moderator7 Dec 2025#51

SURMOUNT-4 used a randomised withdrawal design: everyone titrated, then those on maintenance were randomised to continue or placebo. Continuation maintained effect; withdrawal was followed by regain. The finding is robust but it says nothing about a lower effective maintenance dose, because that was not studied.

1 like 8mo
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BBramleyTL3Regular7 Dec 2025#52
c.balogun, post #13: Mass and charge states: tirzepatide is about 4813.5 Da and on an electrospray instrument you would expect to see charge states mostly in the 2+ to 4+ range, the same as semaglutide. A doubly charged species would appear at about (4813.5 + 2 × 1.008) / 2 ≈ 2408. Go to post

SURMOUNT-OSA is notable because it used an objective physiological endpoint, the apnoea-hypopnoea index, rather than a symptom scale. Two parallel trials, with and without positive airway pressure, addressed the confounder directly. The reduction was substantial in both.

0 likes in reply to #13 8mo
EM
e.mensaTL2 Moderator8 Dec 2025#53

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.

16 likes 8mo
VD
vial_deskTL3Regular8 Dec 2025#54

Picking up post #51: that is the part I would want checked first.

Nausea profile: some people report tirzepatide as less nausea-prone than semaglutide, others report it as more. The trial reported gastrointestinal effects broadly comparable in character. Individual variation is the largest factor.

6 likes 8mo
IA
i.amankwahTL28 Dec 2025#55
JV
j.vandermolenTL3Regular8 Dec 2025#56
m.almeida, post #8: On post #4 — agreed on the reasoning, with one qualification. The GIP component: GIP receptor agonism is thought to amplify the GLP-1 effect on satiety and energy expenditure, but how much of tirzepatide's effect is that and how much is simply achieving higher receptor occupancy remains genuinely open. The mechanistic literature is… 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 #8 8mo
CS
c.serranoTL2 Moderator8 Dec 2025#57

The GIP component: GIP receptor agonism is thought to amplify the GLP-1 effect on satiety and energy expenditure, but how much of tirzepatide's effect is that and how much is simply achieving higher receptor occupancy remains genuinely open. The mechanistic literature is active.

23 likes 8mo
TN
t.nardoneTL3Regular8 Dec 2025#58

The 2.5 mg starting dose is not a therapeutic dose in the sense that weight loss is minimal at that dose. It is a tolerance-testing dose. Confusing the purpose of a starting dose with the purpose of a maintenance dose leads to false conclusions about efficacy.

10 likes 8mo
SD
st.dialloTL2 Moderator8 Dec 2025#59

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.

6 likes 8mo
H
HHidalgoTL2Member9 Dec 2025#60

post #59 answers the question as asked. The question underneath it is different.

Half-life difference: tirzepatide is about 5 days versus semaglutide's week-long. Practically, that means steady state is reached slightly faster and the post-dose swing is slightly larger. Most people do not report noticing the difference in practical terms.

1 like 8mo