Dutasteride blocks both 5AR enzymes. (The enzymes in the body that convert testosterone into DHT which causes baldness). finesteride only blocks one of them.
Also what hair loss products you take is dependent on which AAS you are taking as these products (fin & dutas) with certain steroids such as deca will actually cause increased hair loss.
By inhibiting conversion to DHT, you can also cause an increase in aromatising to oestrogen.
Get generic minoxidil by kirkland signature, same and much cheaper than Regaine.
I personally don't think nizoral shampoo makes a significant difference.