Hi
as the age progresses
testosterone levels drops..but few conditions causing low testosterone includes obesity,
diabetes,high blood pressure,infections of gonoidal tissues ,
Hiv,
Aids etc...since you are saying immunity is low get Hiv tests done consult low immunity can be the cause of recurrent URTI...other causes of low immunity should be ruled out...consult physicians they will do the needful and consult urologist for low testosterone levels