Oral Finasteride Dosing for Male Pattern Hair Loss
The recommended dose of oral finasteride for treating male pattern hair loss is 1 mg once daily. 1, 2
Standard Dosing Regimen
- Finasteride 1 mg once daily is the established dose recommended by the American Academy of Dermatology for men aged 18-60 years with male pattern hair loss 1, 2
- This 1 mg dose produces approximately 50% DHT suppression and PSA reduction after 12 months, similar to the 5 mg dose used for benign prostatic hyperplasia 1
- A Japanese study comparing 1 mg versus 0.2 mg doses found that while both were effective, the 1 mg dose was numerically superior across all efficacy endpoints at 48 weeks 3
Timeline for Expected Results
- Visible improvement typically begins by 12 weeks of treatment 1, 2
- Maximal benefit occurs at 1-2 years of continuous therapy 1, 2
- Long-term efficacy is maintained over 5+ years with continued treatment, but hair loss resumes if treatment is discontinued 1, 2, 4
Efficacy Across Scalp Regions
- At 24 months, finasteride 1 mg produces statistically significant hair growth versus placebo in all scalp regions affected by male pattern hair loss: vertex, anterior/mid scalp, frontal hairline, and temporal hairline 5
- Global photographic assessment shows improvement in 48% of men at 1 year and 66% at 2 years, compared to only 7% with placebo 6
- Hair counts demonstrate that 83% of finasteride-treated men versus 28% of placebo recipients had no further hair loss at 2 years 6
Critical Clinical Considerations
PSA Monitoring Requirement
- Men taking finasteride 1 mg should have their PSA values doubled after 12 months of therapy when screening for prostate cancer 1, 2
- Finasteride reduces serum PSA by approximately 50% after one year at both the 1 mg and 5 mg doses 1, 2, 7
- Consider obtaining a baseline PSA before starting treatment in men approaching prostate cancer screening age (>40-45 years) 2
Sexual Side Effects Profile
- Sexual dysfunction (decreased libido, ejaculation disorders, erectile dysfunction) occurs in approximately 2-4% more patients taking finasteride compared to placebo 2, 7
- The overall incidence of sexual function disorders is not significantly different between finasteride and placebo when accounting for natural aging effects 2
- The magnitude of sexual dysfunction effect (3.21 points on sexual function scales) is relatively small compared to each year of natural aging (1.26 points) 2, 7
- Sexual adverse events typically reverse upon discontinuation and many resolve even with continued therapy 6
Treatment Duration Planning
- This is a long-term commitment - efficacy is maintained over 5+ years, but hair loss resumes if treatment is discontinued 1, 2, 4
- Counsel patients on realistic expectations and the need for continuous therapy to maintain benefits 2
Common Pitfall to Avoid
- Do not use finasteride 1 mg interchangeably with the 5 mg dose intended for BPH - while DHT suppression is similar, the 1 mg dose is specifically studied and approved for hair loss 1
- Ensure patients understand that stopping treatment will result in loss of any hair regrowth achieved, typically returning to baseline within 12 months of discontinuation 2