Finasteride Dosing and Clinical Considerations

Dosing by Indication

The 5 mg dose of finasteride was consistently used across all major clinical trials for BPH, including PCPT, MTOPS, PLESS, PREDICT, and VA Cooperative studies 1, 2
The American Academy of Dermatology recommends 1 mg of finasteride once daily for treating male pattern hair loss in men aged 18-60 years, with visible improvement typically beginning by 12 weeks and maximal benefit at 1-2 years 3
The 1 mg dose of finasteride produces similar DHT suppression and PSA reduction (approximately 50% after 12 months) as the 5 mg dose used for BPH 4, 5

Men taking finasteride at either dose should have their PSA values doubled after 12 months of therapy when screening for prostate cancer 3, 6
Finasteride reduces serum PSA by approximately 50% after one year of treatment at both the 1 mg and 5 mg doses 4, 5

For BPH, long-term studies demonstrate sustained symptom score improvements of 3-4 points maintained for 6-10 years with finasteride 6
For hair loss, efficacy is maintained over 5+ years, but hair loss resumes if treatment is discontinued 3

The American Urological Association implies that finasteride is ineffective for BPH in patients without documented prostatic enlargement (prostate volume >30cc), as it is ineffective in this population 6