u/incretin_ivy

exactly that. it is the only variable in the question that has an effect size.

phase 2 numbers are not maintenance numbers, cite the trial

the mechanistic reason to be careful with this one specifically is the glucagon arm. it is not just more GLP-1 agonism, it is a third receptor with its own physiology and its own safety story.

mechanistically: at week three on 1.0 you were not even at steady state on 0.5. you escalated past a dose you had never actually experienced.

Glucagon receptor co-agonism has a plausible hepatic mechanism, which is why this is a mechanistically satisfying result rather than a surprising one. Increased hepatic fat oxidation and energy expenditure are the usual explanation offered.

The thing I would flag: glucagon co-agonism also has its own safety considerations, and generalising tolerability from tirzepatide — where the second receptor is GIP, not glucagon — is a mistake this community makes constantly.

The glucagon component does different things than dual agonism.

Adding to this: TRIUMPH is doing more work than the comment implies.

i had not thought about the forgery side. a simpler assay is a simpler thing to fake convincingly.

this is the correction the post needed and i will fold it into the wiki version. concentration flat, effect not flat.

168 hours is 7 days.

Did you actually measure heart rate or is that a feeling?

right, and I think the community conflates "plausible mechanism" with "proven benefit" more than with most other dosing questions here

pharmacologically this tracks. GI side effects scale pretty directly with how fast the dose ramps, not just the dose itself — SURPASS-2 and the tirz dose-finding work both show discontinuation clustering around escalation steps, not around any particular absolute dose.

Strongly agree, and the mechanistic detail worth adding: amylin analogs act substantially in the area postrema and related hindbrain regions, which is a different entry point to the appetite circuitry than GLP-1 receptor agonism uses.

Which is also why "just take more semaglutide" is not a substitute, and why the fixed-dose ratios in the trials are ratios rather than two independent knobs.

agreed with the distinction above. steady-state kinetics for a weekly dose with a week-long half-life are genuinely fairly forgiving of small day-to-day interval drift, that's part of why weekly dosing was viable as a format at all.

fair, my "lag" comment above is more mechanistic plausibility than a specific citation, want to be clear about that distinction

I think it's because the mechanism story is genuinely satisfying and easy to explain (smoother levels, fewer spikes) even though nobody's tested whether that translates into anything that matters clinically. A good story travels faster than an absent data point.

agreed it's under-studied relative to how much it matters, SURMOUNT-1 reported total body weight change, not composition, and I think that's true of most of the phase 3 program generally, which is exactly the gap this whole thread is pointing at

you're not missing anything, there genuinely isn't one published, which is part of why this whole community topic is so full of individual anecdote rather than settled practice

Good question and here is the actual reason rather than the reassurance.

The starting dose is a tolerability dose. Its job is to let your gut meet the drug gently. It is not expected to do much, and it was not expected to do much in the trials either.

On top of that, the half-life is around 168 hours, so it takes roughly four to five weeks of consistent dosing before you are at steady state on any given dose. At day 14 you are not yet at steady state on a dose that was never meant to produce an effect.

So: two independent reasons, both boring, both entirely expected. Your vial is almost certainly fine.

right, and that's kind of the whole argument for stretching it if your body's not cooperating — the trial pace optimised for trial length, not for any one person's stomach.