Switching from Reta to Tirz?

What dose are you on with reta right now? How long have you been at that level? One idea I have is staying on tirz long term for maintenance once I reach my goal on reta. That would mean lowering reta when hunger or food noise gets noticeable, then adding tirz to keep it in check without overdoing it, and stepping doses down as things improve. Basically the reverse of how I bridged from tirz to reta.

I'm at 10 mg now for a few weeks. Started at 4 mg. Been on reta for 18 weeks total. I inject every six days.

There isn't any standard way to bridge from reta to tirz. Sounds like you're still trying to lose weight. I've had almost no side effects on either one. Moving from reta to tirz means losing the GCGR part. If I were doing it I'd still come off reta and add tirz to handle appetite. Are you planning to stop reta all at once or taper it?

I plan to taper off.

Tapering should make symptoms easier to handle. I only reached about 5.5 mg on tirz and wasn't at steady state. I began adding small frequent doses of reta to check for sides. Since starting the change I've done two tirz shots that peaked at 4.5 mg and 3.5 mg, spaced a week apart but timed to hunger or food noise. Wednesday will be another week since the last tirz shot. If reta's GLP effect is still strong enough I won't see too much extra appetite or noise. If I do I'll add another dose aiming for a 2.5 mg peak.

A few things puzzle me before any switch. Why start reta at double the usual beginning dose? How many mg is in your vial and how many ml are you injecting for the current dose? I'm wondering if it could be too much too fast or if the volume is causing tissue reactions. Can't speak to the switch or taper but curious about the reactions. Has it been this way the whole time?

I read the reaction starting at 4 mg weekly. Volume could be a factor though I hadn't thought of it before, but five days seems long for a bac water issue to stay red.

Local allergic reactions to any of the GLP meds are fairly common and usually don't go away. Cross reactions are rare so switching to tirzepatide would probably avoid the allergy too, which is likely what you'd need to do.