Dr.PainCLE said:

SURMOUNT-1 landed around 20.9% mean weight loss at 15mg over 72 weeks, against roughly 15% for semaglutide 2.4mg in STEP 1.

Dose-response modeling for tirzepatide: Emax model fitting to the STEP/SURMOUNT dose-finding data shows:

Semaglutide: ED50 ≈ 0.6mg, Emax ≈ -18%, Hill coefficient ≈ 1.3
Tirzepatide: ED50 ≈ 6mg, Emax ≈ -25%, Hill coefficient ≈ 1.5

Clinical implication: most patients achieve >80% of maximal response by the mid-range dose (1.7mg sema, 10mg tirz). Going to the maximum dose provides diminishing returns — possibly not worth the additional side effect burden for some patients. Individualize dosing based on response vs tolerability.

Following on from Dr.Martinez — and this may be the naive question:

How much of the tirzepatide advantage is the GIP component and how much is simply that the dose ladder goes higher in receptor-occupancy terms?

PeptideSynthNJ said:

Dose-response modeling for tirzepatide: Emax model fitting to the STEP/SURMOUNT dose-finding data shows: Semaglutide: ED50 ≈ 0.6mg, Emax ≈ -18%, Hill…

There is a second half to this that has not been said yet. Training does two things here and only one of them is on the scale. It protects lean mass — which is the reason to do it — and it contributes modestly to the deficit, which is the reason people start and then quit when the arithmetic disappoints them. In a deep deficit, resistance work is the priority and high-volume cardio competes with recovery.

OP back with an update, since a thread like this is useless without one.

Reporting back after another eight months at the same dose. Still losing slowly, no new side effects, and no reason I can find to climb further.

pat_auckland said:

Training does two things here and only one of them is on the scale.

True, though the ladder is longer and that is not a neutral detail — six dose steps means six opportunities to stall on the way up, and plenty of people never reach the dose the headline number came from.