From the Guidelines
Finasteride is a medication primarily used to treat male pattern baldness and enlarged prostate (benign prostatic hyperplasia), with a recommended dose of 1mg daily for hair loss and 5mg daily for prostate issues.
Key Points
- Finasteride works by inhibiting the enzyme 5-alpha-reductase, which converts testosterone to dihydrotestosterone (DHT), a hormone that contributes to hair loss and prostate enlargement 1.
- By reducing DHT levels, finasteride can slow or stop hair loss and even promote some regrowth in many men, while also reducing prostate size and improving urinary symptoms 1.
- Side effects may include decreased libido, erectile dysfunction, and decreased ejaculate volume in a small percentage of users, which are typically reversible upon discontinuation 2, 3.
- Women who are pregnant or may become pregnant should not handle crushed tablets due to potential risks to male fetuses 4.
- Results for hair loss typically take 3-6 months to become noticeable, and the medication must be taken continuously for benefits to persist 5.
- Regular follow-up with a healthcare provider is recommended to monitor for effectiveness and any adverse effects 6.
Considerations
- The use of finasteride for prostate cancer chemoprevention is still a topic of debate, with some studies suggesting a potential increase in high-grade cancers 7, 6.
- However, the majority of evidence suggests that finasteride is safe and effective for the treatment of benign prostatic hyperplasia and male pattern baldness 1, 5.
- Patients should be fully informed of the potential benefits and risks of finasteride, including the possibility of increased high-grade cancers, and should be closely monitored by a healthcare provider 6.
From the FDA Drug Label
The development and enlargement of the prostate gland is dependent on the potent androgen, 5α -dihydrotestosterone (DHT). Finasteride is a competitive and specific inhibitor of Type II 5α-reductase with which it slowly forms a stable enzyme complex.
The use of Finasteride (Propecia) is to inhibit the production of DHT (dihydrotestosterone) by blocking the enzyme Type II 5α-reductase, which is involved in the development and enlargement of the prostate gland.
- The main effect of Finasteride is to reduce the levels of DHT in the body, which can help to treat conditions such as Benign Prostatic Hyperplasia (BPH). 8
From the Research
Uses of Finasteride
- Finasteride is used to treat benign prostatic hyperplasia (BPH) by reducing prostate size and improving urinary flow rate and urological symptoms 9
- It is also used to treat male pattern hair loss (androgenetic alopecia) by inhibiting the conversion of testosterone to dihydrotestosterone (DHT), which is implicated in hair loss 10, 11, 12
- Finasteride has been shown to promote hair growth and prevent further hair loss in a significant proportion of men with male pattern hair loss 10, 11, 12
- It can also be used to treat haematuria (blood in the urine) caused by BPH, and has been shown to be effective in preventing new bleeding 13
Mechanism of Action
- Finasteride works by inhibiting the enzyme 5 alpha-reductase, which converts testosterone to DHT 9, 10, 11, 12, 13
- By reducing DHT levels, finasteride decreases the size of the prostate gland and promotes hair growth 9, 10, 11, 12, 13