That doesn't make a whole lot of sense...usually you'd start out on E and a T blocker like spiro or androcur to knock it down at the start, so then you could drop it after it's done it's job. At that point, supposedly the E alone would be enough to keep it at a low level.
Anyways as for herbal DHT blockers, SP and spearmint seem to be the most used. As for pharma T blockers, I listed the two most people take. In the US, you'll almost always get prescribed spiro, abroad it varies more...from what I've read.