It doesn't. It builds up in your system just like beta alanine. Just use it and forget the fancy new versions of creatine, loading phases etc. Just take 5g a day and yer golden.
As for test boosters... Actually working ones are pharmaceuticals which are illegal in most countries. The only way a dietary supplement could actually affect your test levels is a situation where you are severely lacking certain nutrients in your diet and you get those through supplements.