Not sure if this is your first rodeo or not but 20mg is a LOT if its your 1st-10th time IMO.. have had girls with so-so genetics prep for USA's on 10mg.. Keep in mind too, the more clen you use the slower your natural metabolism will get.. Clen will slow your thyroid down when you start sing it.. Take it for 3 weeks straight and go get a blood test to check every thyroid hormone and see what you find out..