As far as natty test boosters go the freeing up of bound testosterone seems to be the most noticeable between one that concentrates on serum levels and free test. So for someone on TRT or androgel it should free up a substantial amount of androgen / testosterone which leaves it available for anabolism as well as androgenic traits like libido and positive aggression, mood elevation, all the good aspects.
Yes someone on TRT is going to be shut down already as a matter of fact that is the only legal reason for someone to get on anyway is hypogonadism. EI Having to low levels of testosterone.