shrinkage
See now I've had the effects, but its never posed a problem. when ever the draft comes up the soldier is ready for battle, and back at fighting size.
Shrinkage is a common effect with any amphetamine like substance see also - CRYSTAL DICK .... its all just temporary, and it should still work, if not you may be having issues elsewhere, although on occasion it has been known to "prolong ejaculation" to the point of not caring anymore.