I started taking HCG from the begining, in my opinion and my doctor's opinion you should do it from the begining to mantain testicular function,size etc. it will depend, for example if you dont want to have kids in the future you can add HCG just to mantain testicular size, and doing it time to time, but if you want to have kids i think is better to stay on HCG more frequently and also HMG time to time. Thats my protocol because im young and i want to have kids one day.