I take Epi in a pulsing fasion as recommended by Dr. D. I Pulse Epi three day/week since this is my current workout protocal. I use either formestane or Diesel Test Hardcore on none workout days. This seems to work well and as far as I can tell I have not had a problem with shutdown. The longest I have pulsed is 6 weeks. I read where Dutchman sometimes goes longer.