I usually need up at about 120mcgs a day. Start low and see how your body reacts and slowly up your dose until you find what works for you. Most are between 100-140mcgs but u know buddies who are fine at 80-100.
Two good posts bighench... Not.
Don't run clen and Anavar (var) . not without test, and that's a whole other topic I won't get into. Anavar (var) w/o test is for women.
Oh and don't worry about your heart beat. Seriously? Check your BP regularly while using clen