I do not see the reason to combine them. From everything I have come across, retatrutide covers the same ground as tirzepatide and may do it better while preserving more muscle, so a higher dose of retatrutide alone should be enough.
I realize this topic has been covered many times, but I still want input from people I already know here rather than strangers elsewhere. I am currently using 6 to 7.5 mg of tirzepatide on Friday nights and have started adding 2.5 mg of retatrutide on Monday nights for the first month. I may raise the retatrutide later while lowering the tirzepatide. My goal is to get the advantages of both compounds even though some sources advise against combining them.