Switching from semaglutide to tirzepatide — 6 month update

Dr.NutriCornell 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.

That holds for the injectable. The oral formulation has different absorption behaviour and the dose numbers are not interchangeable, which is worth saying out loud because people quote them as if they were.

Worth separating that from tirzepatide, which this thread keeps folding into the same question. They behave differently and the advice does not transfer.

mark_tokyo said:

The dose-response is real but shallow at the top.

This answered a question I did not know how to ask. I will report back once I have actually tried it.

Dr.NutriCornell 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.

I will push back on the "any working dose is fine" framing. The maintenance evidence sits overwhelmingly at the top studied dose, and the extension data shows regain tracking dose reduction rather than tracking stopping. Holding low is reasonable; pretending it is evidentially equivalent is not.

The figures, for anyone assembling their own picture. Practical numbers: half-life about 5 days, steady state 3 to 4 weeks, ladder 2.5 / 5 / 7.5 / 10 / 12.5 / 15mg, and the maintenance doses with published data behind them are 5, 10 and 15mg.

Moderator note: reminder that nothing in this thread is medical advice, and that clinical claims need a source. Carry on.