You can thank Russia for having balls when it comes to biochemistry.
Some of these steroids still have negative effects on your libido and endocrine system, but a lot of users want brawn and brains, not babies. There's a wide selection now from harmless racetams to hgh analogs that will blow up your muscle. Some people play it safe, some go to the edge, but making steroids more selective at target tissue gives us the option.
Back then it was just DHT and ephedrine, the first makes your body deregulate and become dependant, while the other drastically increases cortisol and adrenaline (eating your skin, meth mouth etc)
Now we got Somatropin which harmonises and up-regulates your natural endocrine triad (gonads, petuitary, and thyroid)
The racetams are stereoscopic, enter neurons at any post synaptic charge, and releases excess voltage potential. After a month your CNS will start jiving to this phenomena and your mental acuity and plasticity will go through the roof.