Endocrinologists never agree about anything.
As far as the physiology is concerned. As soon as you start on the oestrodiol (Estrofem) the effect is to stimulate your liver to produce more of a globulin called Sex Hormone Binding Globulin (SHBG), you will see it on your blood tests as SHBG. This binds free testosterone and removes it from your system. The oestrodiol is then binding to its receptors and the fun starts. After a while you may still be producing significant levels of free testosterone and the desire is to reduce that. Hence anti androgens (Spiro), that block the receptors where Testosterone binds are given. Obviously if your SHBG has increased and reduced your levels of T you don't need the AA.
But depending upon your age and your health and whatever, some medics like to wait to see what the oestrogen will do by its self and then give AA if required or give both together. It can depend on your age, a young 'male' body may be pumping out a heap of T that needs AA and oestrogen to counter it. A person producing low levels of T may not need AAs at all, ever. Some people may produce so much T that they need an orchi plus AA to stop it. There do not appear to be many set rules and medics who treat TG people seem to use their experience to go with what has worked for them.
So the best advice is to follow the protocol your medic has given and most importantly ask them, no, tell them to explain what they are doing and why. The write it down so you know. It is your body and your life.
Good Luck and ask questions but as said, not dosages and always seek medical advice.
Cindy
