21% bf is too high to be running a cycle. You need to get your body fat down a bit, around 15%. You could do a clen/keto cycle but your cardio's going to be shot. My resting heart rate on Clen is close to 100bpm. You could do a low dose clen(40mcg/ed)/keto/fasting cardio for fat loss. I was on Test (300mg/wk)/Mast (300mg/wk) when I got down to 9.5% bf (bod pod). When added Tren (100mg/wk)/T3 (25mcg/ed)/fasted cardio I got down to 7% bf (bod pod). The worst part was the eating. I had to be SUPER strict with what I ate. I normally walk around at 11% to 12%.