It’s true that scientific studies show
these steroids don’t bind well to the
androgen receptor, but they do have some
binding. So let’s say someone is using
100 mg/day total of both, which is 700
mg/week. Especially when you consider
that the half life is longer than for
free testosterone, even though the potency
(degree of receptor binding per mg) is
lower, you still do have some significant
binding. It’s not as if your androgen
receptors are getting castrated. Might
even be somewhat over normal physiological,
especially since in the early stages of
the cycle you may have significant remaining
natural T as well.
But other steroids will give a lot more binding
than these do and you can get greater
total effect at the androgen receptor and
greater total mass gains by combining these
steroids.
The fact that you can make good gains
without stacking a Class I is a testament
to the fact that the Class II anabolism
not dependent on the androgen receptor
is quite significant.