I didn't switch, I began with Dutasteride and am still on it 9 months later but since no-one else has commented here yet I may as well.
A single dose of Dutasteride per day can reduce your T by 90%+
In my case, I went from a baseline T-level of in three-and-a-half months.
I didn't notice anything at all in the way of side effects.
Note that Dutasteride has a very long half-life of 3 months as against Finasteride's few hours. I found graphs and (knowledgable) discussion on the internet quite easily.
You COULD take all your first months supply over the first couple of days as a "loading dose" which will get you up to peak effect quicker - study the info for yourself and decide. - I didn't know this was possible when I started, so I didn't but had I known, I probably would have.
A final note - despite taking the same dose of Dutasteride exactly as before, my T level rose again up to over the last 3 months and no-one knows/has told me why.
That said, my friend who is on Finasteride had exactly the same thing happen but it doesn't seem to happen often so is presumably down to our personal chemistry(s)
- the solution they have indicated is the Zoladex implant three-monthly but the PCT refused to fund it for her and as yet a decision hasn't been made for me.
