What about Direct and Indirect Steroids?
If we are to evaluate the proposed indirect effects of testosterone and decide on the efficiency of synthetic anabolic/androgenic steroids, we must try not to be tricked into believing that there are two classes of steroids capable of inducing muscle growth. The claim that there are two distinct groups or categories of steroids overlooks the fact that all trade steroids stimulate not only muscle growth but also androgenic effects. These traits cannot be completely separated at this time, which is why it is obvious that they all activate cellular androgen receptors.
I think some people started thinking about classifications of direct and indirect steroids when they found out why highly powerful anabolic steroids such as oxymetholone or methandrostenolone did not have a high affinity for receptors.
This kind of thinking fails to acknowledge other features that cause these compounds to have greater strength such as their long half-lives, estrogenic activity, and weak interaction with restrictive binding proteins. Although some compounds may facilitate growth differently, promoting it indirectly even, where a few synergistic drug combinations might just be beneficial; all these compounds exert their effects through the androgen receptor.
Also, you need not take seriously ideas like steroids X and Y must never be stacked together since both compete for the same receptor in stimulating growth while combining X and Z would make sense as they act via distinct mechanisms. Therefore, such classifications are merely hypothetical and on sound investigation untenable.