By inhibiting 5α-reductase and thus preventing DHT production, finasteride reduces androgen signaling in tissues like the prostate gland and the scalp. In the prostate, this reduces prostate volume, which improves BPH and reduces risk of prostate cancer. Finasteride reduces prostate volume by 20 to 30% in men with benign prostatic hyperplasia.  Inhibition of 5α-reductase also reduces epididymal weight, and decreases motility and normal morphology of spermatozoa in the epididymis.  Neurosteroids like 3α-androstanediol and allopregnanolone activate the GABA A receptor in the brain ; because finasteride prevents the formation of neurosteroids, it may contribute to a reduction of GABA A activity (see also neurosteroidogenesis inhibitor ). Reduction of GABA A receptor activation by these neurosteroids has been implicated in depression , anxiety , and sexual dysfunction .