the person you mentioned is on RPFA great youtube channel with a cool guy? The deltoid deathstar man himself?
Hes realy into hormones and the endocrine system and runs his own buisness selling pre- and post workouts and other supplements which hes formulating himself. I think he also works with or for a hormonal replacement therapy company/clinic. Or does he own one? Idk.
The regular gym bro can learn alot from that channel. Just check some videos out if your interested in it.