There are lots of different studies on this issue, so search it out. Why start a thread and then answer your own question and saying nobody answered it so your answering it. Yes I udnerstand how it affects your natural testosterone by dropping natty test levels by increasing prolactin after sexual stimulation. So temporarilly it will lower your natty test levels. Whether or not it affects exogenious testosterone i'm not sure. This is Lounge Material anyways.