Finasteride and Testosterone Levels

Clinical Considerations and Side Effects

Sexual side effects, including erectile dysfunction, decreased libido, and ejaculation disorders, are reported in approximately 2-4% more patients taking finasteride compared to placebo, according to the Journal of Clinical Oncology 1
In the Prostate Cancer Prevention Trial (PCPT), 67.4% of men on finasteride reported erectile dysfunction compared to 61.5% on placebo, with a relative risk of 1.10, as reported by the Journal of Clinical Oncology 3

When monitoring PSA levels in patients taking finasteride, clinicians should be aware that PSA is suppressed by approximately 50% after 12 months of therapy, as noted by The Journal of Urology 4
The magnitude of sexual dysfunction effect is relatively small compared to natural aging, with a finasteride effect of 3.21 points and each year of aging contributing 1.26 points on the sexual function scale, according to the Journal of Clinical Oncology 1