I am 18years of age an can tell that my testicles has shrunk in size. at a younger age had an addiction. maybe that is the reason. what i wanted to know was if i do semen retention til my semen tract is back full will my testicles get back full size?

You should be evaluated by a urologist or endocrinologist. Examination, blood test and possible semen exam are required for answering your question.

' Semen retention' does not change the size of the testicles. For correct diagnosis and management pl see a Urologist. Your self diagnosis might be wrong and pl stay away from all drugs and supplements. Wishing you good luck