Type II metabolizes testosterone to DHT in the prostate gland, liver and skin. In years 2-4 of the study, there was no significant difference between treatment groups in the incidences of impotence, decreased libido and ejaculation disorder. The buy finasteride online billig serum level of any CYP3A4 substrate, such as Dutasteride, will be elevated in the presence of GF juice. This drug is highly effective at stopping the conversion of testosterone into DHT. In years 2-4 of the study, there was no significant difference between treatment groups in the incidences of impotence, decreased libido and ejaculation disorder. Finasteride, 5-alpha-reductase inhibitor, is used as chemopreventive agent because it blocks the conversion of testosterone to its byproduct which promotes prostate tumour growth.