By brain level, he means to say that this drug will disrupt the production of two hormones (luteinizing and follicle stimulating) produced by the pituitary gland at the base of the brain. At first, it will actually increase their production but after weeks of constantly stimulating the receptors (desensitization), production will SHUT down completely. Luteinizing hormone signals/tells the testicles to produce androgens, namely testosterone so that when its production is shut down, testes will stop producing androgens. Follicle stimulating hormones induces spermatogenesis. Both hormones eventually being suppressed, you will no longer produce sperm, have erections and experience androgenic symptoms. This will indeed allow estrogen to work better, unopposed BUT interestingly, estrogen also reduces both these hormones as well and appears to exert anti-androgenic effects in cells. So the combination of both is quite effective.
Whether this drug is more effective than Spiro depends on how much Spiro you take and how you respond to the dose. Spiro works somewhat differently. Being on this drug is essentially like being post-op, having no testicles as testicles no longer function.
I think you should follow your doctor's recommendations. I personally prefer this drug to spiro but to each their own. I think most don't take this drug because it is expensive but in your case, it's most probably covered and that's why it's used. If you don't like this doctor's approach, then find someone else. Your call. Or wait and see. If months from now, you are not happy with results, then act accordingly, either by discussing about other options with this doctor or finding another one.
Good luck!
