Tirzepatide tummy troubles - Sema a better bet?

3 months of feeling like crap on Sema and then switching to Tirz and feeling much better is the reverse of what the OP is dealing with. The individual variation in which direction causes more GI issues is genuinely unpredictable. Starting low and slow is the right advice regardless - 5mg on the second shot is a steep early entry.

Sema causing nausea and then having essentially no side effects from tirz, reta, and cagri is the opposite of what the OP is experiencing. The individual variation in which direction causes GI problems is genuinely unpredictable. 5mg on the second shot after starting is a steep early jump - what was the first shot dose?

The individual variation on nausea between sema and tirz is wide enough that general advice isn't very useful. The trial-and-see approach is genuinely the only way to find your personal response. If tirz was 10 days of nausea at 5mg, stepping back to a lower dose first would have been worth trying before concluding it doesn't work.