From the Guidelines
The recommended dosing of dutasteride (Avodart) for androgenetic alopecia is typically 0.5 mg taken orally once daily. This medication works by inhibiting both type I and type II 5-alpha-reductase enzymes, which convert testosterone to dihydrotestosterone (DHT), the hormone primarily responsible for male pattern hair loss. By reducing DHT levels more effectively than finasteride (which only inhibits type II 5-alpha-reductase), dutasteride can help prevent further hair loss and potentially promote hair regrowth.
Key Points to Consider
- Dutasteride is not FDA-approved specifically for hair loss treatment in the United States, though it is used off-label for this purpose 1.
- Patients should be aware that results typically take 3-6 months to become noticeable, and the medication must be continued indefinitely to maintain benefits.
- Side effects may include decreased libido, erectile dysfunction, and ejaculatory disorders in a small percentage of users.
- Women who are pregnant or may become pregnant should not handle dutasteride due to potential risks to male fetuses.
Mechanism of Action
Dutasteride inhibits both the type 1 and type 2 isoforms of 5-a reductase, causing a greater and more consistent decrease in DHT compared to finasteride 1. This decrease in DHT levels is associated with a reduction in hair loss and potentially an increase in hair regrowth.
Important Considerations
- The effects of dutasteride on PSA levels have been studied, and it has been shown to decrease PSA levels by 50-60% after 1-2 years of therapy 1.
- However, the amount of PSA suppression with long-term dutasteride treatment has not been reported, and patients should be monitored regularly for any changes in PSA levels 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Dosing of Dutasteride for Androgenic Alopecia
The recommended dosing of dutasteride for androgenetic alopecia is as follows:
- 0.5 mg daily, as shown in studies 2, 3, 4, 5 Some key points to consider:
- Dutasteride inhibits both type I and type II 5-alpha-reductase, which may make it more effective than finasteride for treating androgenetic alopecia 2, 4
- The efficacy of dutasteride has been demonstrated in clinical trials, with significant increases in hair count and decreases in thin hair count 2, 5
- Common side effects of dutasteride include sexual dysfunction, which is typically reversible 2, 5
- The use of dutasteride for androgenetic alopecia is off-label, but it has been approved for this indication in some countries, such as Japan and South Korea 4
Comparison with Other Treatments
Dutasteride has been compared to other treatments for androgenetic alopecia, including:
- Finasteride: dutasteride has been shown to be more effective than finasteride in some studies 2, 4
- Minoxidil: dutasteride has been shown to have a different side effect profile than minoxidil, with more sexual dysfunction and fewer cardiovascular side effects 4
- Topical treatments: topical dutasteride is being developed as a potential treatment for androgenetic alopecia, which may reduce the risk of systemic side effects 6