If you have an increase in endogenous testosterone, you're likely going to get an increase in DHT formation. However, and this is important, it's doubtful that such an increase is of any clinical significance. You're talking about a relatively small increase in endogenous testosterone to begin with (i.e., little substrate) then coupled with a small amount being reduced to DHT (around 4% depending on the source) which in the end results in very little elevation.
Androgenic alopecia is generally only a concern when you're talking about individuals taking large dosages of exogenous testosterone or other androgens.
Although, in certain cases where one is highly predisposed to androgenic alopecia (perhaps largely increased expression of 5 alpha-reductase), you could perhaps argue that increasing endogenous testosterone, even to a small degree, could be deleterious.
This same line of thinking also applies to the prostate. In short, unless you have a strong history of prostate problems, a small to moderate increase in endogenous testosterone shouldn't be a major concern.