What is the efficacy of Finasteride (1 milligram) for the treatment of androgenetic alopecia (hair loss)?

From the Guidelines

Finasteride 1 mg daily is the recommended treatment for male pattern hair loss, as it has been shown to be effective in promoting hair growth and slowing down hair loss. The medication works by blocking the conversion of testosterone to dihydrotestosterone (DHT), which is the hormone responsible for hair follicle miniaturization in genetically susceptible men 1. The recommended dosage is one 1 mg tablet taken orally once daily, with or without food. Results typically begin to appear after 3-6 months of consistent use, with maximum benefit usually seen after about 1-2 years. To maintain results, continuous treatment is necessary as hair loss will resume if the medication is stopped.

Some key points to consider when prescribing finasteride 1 mg daily for hair loss include:

• Potential side effects, such as decreased libido, erectile dysfunction, and decreased ejaculate volume, though these occur in only a small percentage of users (about 2-4%) and often resolve with continued use 1
• Contraindication in women who are or may become pregnant due to potential risks to male fetuses
• The possibility of combining finasteride with topical minoxidil 5% solution or foam applied twice daily to the scalp for best results
• Regular follow-up with a healthcare provider to monitor effectiveness and any potential side effects

It's also important to note that finasteride 1 mg daily has been shown to decrease PSA levels by 50% after 12 months of therapy, similar to the 5 mg dose, which is used for other indications 1. However, this effect on PSA levels should be taken into account when judging the significance of a PSA level, and a multiplier of 2 may be used as a criterion for biopsy.

From the FDA Drug Label

The development and enlargement of the prostate gland is dependent on the potent androgen, 5α -dihydrotestosterone (DHT). Type II 5α-reductase metabolizes testosterone to DHT in the prostate gland, liver and skin. Finasteride is a competitive and specific inhibitor of Type II 5α-reductase with which it slowly forms a stable enzyme complex. In a separate study in healthy men treated with finasteride 1 mg per day (n=82) or placebo (n=69), mean circulating levels of testosterone and estradiol were increased by approximately 15% as compared to baseline, but these remained within the physiologic range

Finasteride 1 mg is used for the treatment of hair loss, and it works by inhibiting the production of DHT, a potent androgen that contributes to hair loss.

• The mechanism of action of finasteride involves the inhibition of Type II 5α-reductase, an enzyme that converts testosterone to DHT.
• Clinical studies have shown that finasteride 1 mg per day can increase circulating levels of testosterone and estradiol by approximately 15% compared to baseline, while remaining within the physiologic range 2.

From the Research

Efficacy of Finasteride 1 mg for Hair Loss

• Finasteride 1 mg/day has been shown to promote hair growth and prevent further hair loss in a significant proportion of men with male pattern hair loss 3, 4, 5.
• The improvement in hair count reported after 1 year is maintained during 2 years' treatment 3.
• In men with vertex hair loss, global photographs showed improvement in hair growth in 48% of finasteride recipients at 1 year and in 66% at 2 years compared with 7% of placebo recipients at each time point 3.
• Hair counts in these men showed that 83% of finasteride versus 28% of placebo recipients had no further hair loss compared with baseline after 2 years 3.

Safety and Tolerability

• Therapeutic dosages of finasteride are generally well tolerated 3, 4, 6.
• The overall incidence of sexual function disorders, comprising decreased libido, ejaculation disorder and erectile dysfunction, was significantly greater in finasteride than placebo recipients (3.8 vs 2.1%) 3.
• All sexual adverse events were reversed on discontinuation of therapy and many resolved in patients who continued therapy 3.
• No other drug-related events were reported with an incidence > or =1% in patients receiving finasteride 3.
• Most events were of mild to moderate severity 3.

Comparison with Other Treatments

• The clinical efficacy of oral finasteride has not yet been compared with that of topical minoxidil, the only other drug used clinically in patients with male pattern hair loss 3.
• Topical finasteride may be an alternative for those concerned about the oral formulation's systemic side effects, with similar efficacy to oral finasteride 7.
• A combination of topical minoxidil and topical finasteride may enhance efficacy 7.

Dosage and Administration

• Finasteride 1 mg/day is the optimal dose for the treatment of men with male pattern hair loss 5.
• Efficacy was demonstrated for all end points for finasteride at doses of 0.2 mg/day or higher, with 1 and 5 mg demonstrating similar efficacy that was superior to lower doses 5.