What is the normal dose of finasteride (BPH/androgenetic alopecia treatment)?

Normal Dose of Finasteride

The normal dose of finasteride is 5 mg once daily for benign prostatic hyperplasia (BPH) and 1 mg once daily for androgenetic alopecia (male pattern hair loss). 1

Dosing by Indication

For Benign Prostatic Hyperplasia (BPH)

• Finasteride 5 mg once daily is the FDA-approved dose for BPH treatment, whether used as monotherapy or in combination with an alpha-blocker such as doxazosin 1
• This dose may be taken with or without meals 1
• The 5 mg dose was consistently used across all major clinical trials for BPH, including PCPT, MTOPS, PLESS, PREDICT, and VA Cooperative studies 2
• Therapeutic response occurs at doses of 0.5-100 mg/day for prostate regression, but 5 mg once daily is the recommended standard dose 3
• Doses above 5 mg/day provide little additional clinical benefit 4

For Androgenetic Alopecia (Male Pattern Hair Loss)

• Finasteride 1 mg once daily is the recommended dose for treating male pattern hair loss in men aged 18-60 years 5
• The American Academy of Dermatology recommends this dose with counseling that visible improvement typically begins by 12 weeks, with maximal benefit at 1-2 years 5
• The 1 mg dose produces similar DHT suppression and PSA reduction (approximately 50% after 12 months) as the 5 mg dose used for BPH 2, 5, 6
• This lower dose was specifically studied in the Finasteride Study Group trials, which included both 1 mg and 5 mg arms 2

Important Clinical Considerations

PSA Monitoring

• Men taking finasteride at either dose should have their PSA values doubled after 12 months of therapy when screening for prostate cancer 5, 7, 6
• Finasteride reduces serum PSA by approximately 50% after one year of treatment at both the 1 mg and 5 mg doses 2, 5, 6
• In men aged 40-49 years taking 1 mg daily, median PSA decrease is 40% (95% CI 34-46%), while in men aged 50-60 years, the decrease is 50% (95% CI 44-57%) 6

Duration of Treatment

• For BPH, symptom improvement may take several months, as finasteride has a slower onset of action compared to alpha-blockers 7
• For hair loss, efficacy is maintained over 5+ years, but hair loss resumes if treatment is discontinued 5
• Long-term studies demonstrate sustained symptom score improvements of 3-4 points maintained for 6-10 years with finasteride for BPH 7

Common Pitfall to Avoid

• Do not use finasteride for BPH in patients without documented prostatic enlargement (prostate volume >30cc), as it is ineffective in this population 7
• The medication specifically requires prostatic enlargement to be effective for LUTS secondary to BPH 7