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How comparable are tirzepatide and semaglutide on the evidence available?

Asked 31 Mar 2026Modified 15 days agoViewed 3.3k times
13

Setup, so nobody has to ask: tirzepatide · semaglutide.

I am trying to choose between two options that are usually discussed as though only one exists.

I am not optimising for price, but I am not indifferent to it either.

Which axes does this decision turn on?

clinical-trials
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tirzepatide

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askedseamus_brady15k1831 Mar 2026

1 Answer

Sorted by votes
9

Answer first: read the primary endpoint, the comparator and the population before you read the effect size. Almost every argument on this site about a trial is really an argument about one of those three.

Intention-to-treat and per-protocol analyses answer different questions. ITT asks what happens if you offer the treatment; per-protocol asks what happens if it is taken as directed. The gap between the two is a measure of how tolerable the protocol was.

Trial populations are selected. Exclusion criteria in this class routinely remove people with significant renal impairment, prior pancreatitis and unstable psychiatric illness, which is exactly the population the results are then quoted for.

The cardiovascular outcome programme in this class runs to several large randomised trials — LEADER for liraglutide, SUSTAIN-6 and SELECT for semaglutide, REWIND for dulaglutide — and they are the reason the class is discussed as more than a weight intervention.

The caveat is that trial evidence is about licensed product administered under supervision. None of it transfers automatically to research-grade material of unverified content.

Read the protocol and the statistical analysis plan if the result matters to you. Both are usually published alongside.

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answeredDr_Tomas_Kral53k3815 Jul 2026
Thank you for separating the surrogate from the outcome. That distinction gets lost constantly. – nadia_kowalczyk 7 months ago
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Ask PeptideStack is a static archive. Posting is closed, but the norms are worth stating: answer the question that was asked, show your working, cite the trial or the certificate, and say plainly where the evidence runs out.

Not medical advice. Research-use-only compounds are not approved for human use.