different people use different dosages. Merck the people that created finasteride say that any more than 1mg will be wasted.
Although I am no researcher, I have found that 2.5 mg works alot better for me and is cheaper because I buy proscar instead of propecia.
Anyways it depends if youre not getting that much of a reaction with 1mg you can up the dose.
There is also a new drug out for hairloss that blocks both DHT receptors as opposed to the one that finasteride blocks. It is called Dutasteride. Do a search on it, it is a fairly new drug and has not been oked by the FDA for hairloss as of yet but has ben approved for Prostate cancer.
Its pretty expensive also...