Inclusion Criteria:

• Initial biopsy, performed at UHN, of at least 8 cores with no evidence of cancer (HGPIN or ASAP allowed)
• PSA < 20 ng/ml
• Able to swallow and retain oral medication
• Able to read and write (IPSS questionnaire is self-administered), understand instructions related to study procedures and to give written informed consent.

Exclusion Criteria:

• Glucocorticoids, except inhaled or topical, are not permitted within 3 months prior to visit one.
• Concurrent and previous use within the past 12 months of the following medications: Finasteride (PROSCAR, Propecia), Dutasteride (Avodart), Any other investigational 5 alpha-reductase inhibitors, Anabolic steroids, drugs with antiandrogenic properties.
• Participation in an investigational or marketed drug trial within the 30 days prior to the first dose of study drug or anytime during the study period.
• Abnormal liver function test (greater than 2 times the upper limit of normal) for alanine aminotransferase, aspartate aminotransferase, or alkaline phosphatase; or bilirubin > 1.5 times the upper limit of normal.
• Serum creatinine > 1.5 times the upper limit of normal.
• Any unstable serious co-existing medical conditions including but not limited to myocardial infarction, coronary bypass surgery, unstable angina, cardiac arrhythmias, clinically evident congestive heart failure, or cerebrovascular accident within 6 months prior to screening visit; uncontrolled diabetes or peptic ulcer disease which is uncontrolled by medical management.
• History of any illness (including psychiatric) that, in the opinion of the investigator, might confound the results of the study or pose additional risk to the subject.
• Known hypersensitivity to any 5 alpha-reductase inhibitor or to any drug chemically related to finasteride.