"they" have bugger-all ethics...... and don't call me Shirley!
Seriously, the reason you can't buy certain drugs today that passed all their clinical trials etc, is because long-term they turned out to have serious adverse effects (this occurred recently with an approved appetite suppressant). You are putting yourself in a perilous situation - if the trial drug causes an unforseen cardiac arrhythmia for example, is your payment enough to make up for the loss of your aviation medical?