I'm running exactly this. On a 6D protocol so every 2days is another shot. I did it to break a stall; first with Tirz, then added Cagri, then added Reta. Cagri doesn't seem to affect me as much as many others have posted. I posted this in a thread earlier this week, but here it is again, because it applies to your question.
I went up to 10mg Tirz/6D over 4 months, and started picking up the usual symptoms; tinnitus, prickly skin/allodynia, so I didn't want to raise the Tirz dose any more. Dropped 40 lbs in that time. Then big month-long plateau.
I added Cagrilintide at 500mcg/6D. No change, no effect. Added Retatrutide at 1mg/6D (each staggered 2D), minimal change. Raised up to 1mg Cag, 2mg Reta, minimal change.
Finally raised up to 2mg Cagri/6D, and Reta 4mg/6D, finally with the 12mg Tirz/6D. That did it, weight loss is moving again. But wow, those first 2 nights after the ramp up in dosage, the skin sensitivity/borderline pain was the first time I ever thought about stopping Peptides since starting 7 months ago.
Things have gotten marginally better and I'm not contemplating stopping this experiment outright. Maybe I've set too ambitious of a goal? I started at BMI 40.0, and the target now is <30.0 BMI (so from Morbid Obesity to the high end of just "overweight, and not "obesity"). I didn't think that was asking too much.
I will admit that I've moved the goal 3x since starting. I was managing expectations, but it's worked so well I've kept moving the goalposts to get closer to a healthy weight. Currently 7lbs from what I believe is the final goal/BMI 29.something.
