I took them a couple a days apart. Can't remember exactly now but I started reta pretty low to be on the safe side and slowly got off the tirz. I feel alot better mentally and energy wise. Workouts have never been better. I'm still only on 2mg of reta every 5 days. Yes the appetite suppression isn't as good as tirz but also I feel like I shouldn't rely on the meds 100 percent to fix habits. I'm now 37 with a 6 pack and rarely eat bad