My friend and I have been cycling pretty much the same thing for a while now, I've always put on some good gains but my friend however seems to diminish in size and weight every cycle. We both were using pH's for about 4 years but his gains which started off great are now next to nothing. I decided to try doing a testosterone cycle and invited my friend to do the same. He has an increase in sex drive but not a single pound of weight after 4 wks. Not even water weight. I on the other hand have gained some nice pounds. We are both using the same gear I purchased. Can the body become immune to the use of synthetic's? I have no answer to give him so hopefully someone here can help.