OK - the following assumes that you are not using any anti-androgens already because you only posted two sentences. Not a lot to go on....

I have been using minoxidil for about a year now and have hair on spots that have been clear for 10 years. Not brilliant hair but enough to be easily seen and to fill the blank with some colour. Recently I have started using finasteride as well because I have been told that the two work better together than either alone. I get Proscar tablets and chop them into four to get the equivalent dose to propecia. It is a LOT cheaper this way because
Proscar
is propecia, just at a higher dose
Proscar is for prostate = unpopular = low price
Propecia is for hair loss = very popular = high price
I bought a months supply of Proscar for £14 ( = $20-ish) and quartering each pill gives me a four month supply. Propecia for the same period would cost me about £70 ($120).
Some warnings about Finasteride.
1. Keep it away from women
especially pregnant ones. Even minute doses are dangerous
2. Do not donate blood for 6 months after you stop Finasteride
3. It may give you classic migraines (flashy lights). I found it did this if I drank too much coffee
4. It is something of an anti-androgen because it supresses DHT. You may get boob growth.
5. If you are trying to start a family,
stay off finasteride6. It can turn your one-eyed trouser snake into Mr Limpy.
I have only started using it so it is too soon to see any result. Both Minoxidil and Finasteride will cause some hair to fall out in the first few months. This is normal and is scary and many people panic and stop at that point. The hair falling out is cause by newer hair starting a growth cycle and pushing older, resting hair out. You have to use them for a minimum of four months to see if there are any effects and many people say one year.
The down side to both is that if you stop using them then the hair that the treated can drop out. Unless you have your testicles removed first...