You can start off by easiliy obtaining testosterone cream from a urologist after a few tests usually covered by most health insurances.
Once that gets you some results, you can move to HGH, EPO, etc. by use of prescriptions of people who died of the diseases they were being treated for.
Once you start to really show promise, the people who invest in such activity will offer you more and better opportunities to improve.
I, do not and have not, done any of these.