you are confused.
Let's try and clear this up:
DHT is produced from testosterone via the 5-alpha-reductase enzyematic process. DHT causes hair loss - this is documented. The only way to block DHT from attacking the scalp is use finasteride (Propecia or Proscar). Recommended dose is 1mg/day. Other crap like saw palmetto does not work nearly as well or at all.
Estrogen is produced from testosterone via aromatization. Arimidex will prevent aromatization from occuring - it is an aromatase inhibitor. Clomid or Nolvadex will not prevent aromatization, they will just block estrogen at the receptor sites and prevent it from binding. As far as I know, estrogen has not been implicated to cause hairloss. If it were then Arimidex would be a hairloss med - and obviously it is not.
My advice - use Propecia or Proscar at 1mg/day when doing Test, along with Clomid at 50mg/day to prevent gyno, etc... I'm not a huge Arimidex fan as completely inhibiting estrogen production makes most guys feel like shit (having a little estrogen in you helps with mood) - and most guys overdo the dosing.
DrG