i stopped HGH after taking it for several years. i was no longer feeling the initial benefits i had experienced in the begining and it was quite costly. it has been over 5 years and I am still doing great. have not notices any shrinkage and performance problems. I am 72 and had a vasectomy 25-30 years ago, so not certain about you specific concerns, however HGH can have negative side effects as i am certain you are aware.