When your body has enough testosterone, the brain does not send the LH signal to your testicles. Therefore, you will not make any testosterone until your levels drop to below normal and the signal returns, stimulating production. Since you are getting testosterone from an outside source, your brain is most likely not sending that signal to your testicles. Over time, the old adage of “use it or lose it” comes into play and your testicles will shrink in size. The time is different for every man and the amount of “shrinkage” is different for every man. Fortunately, the HCG will quickly restore the size and function.