Effectiveness of Dutasteride in Treating Hair Loss: Studies

Effectiveness of Dutasteride in Treating Hair Loss: Studies

Dutasteride is a medication developed primarily to treat benign prostatic hyperplasia. It belongs to a class of drugs called 5-alpha-reductase inhibitors which block the conversion of testosterone into dihydrotestosterone or DHT. It is essentially a DHT blocker. Its mechanism of action and pharmacodynamics have also made it a medication for treating hair loss in men due to androgenetic alopecia and as a part of hormone therapy in transgender women.

Understanding Why Dutasteride is Effective in Treating Hair Loss and Promoting Hair Growth: Evidence and Explanation from Studies

Evidence According to Studies

There are different causes of hair loss. There are also different categories or types of hair loss. An established and growing body of studies has investigated and documented the effectiveness of dutasteride in treating and preventing hair loss in men due to androgenetic alopecia or male pattern baldness and in promoting hair growth. Take note of the following findings and conclusions that serve as evidence for its effectiveness:

Researcher D. Stough compared the efficacy of dutasteride versus placebo in 17 pairs of identical twin males with male pattern hair loss over a 1-year period. Each pair of twins was placed in either a group that took the medication or a placebo or control group. Results revealed that the group of participants who took dutasteride at a dose of 0.50 milligram per day had reduced hair loss progression and noticeable hair growth while those in the placebo group had visible hair loss progression.

A systematic review by researchers M. E. Herz-Ruelas that included a pool analysis of four studies mentioned that taking oral dutasteride resulted in a mean change in hair growth of 15.92 hairs per square centimeter. It concluded further that the oral route seemed to be the optimal treatment modality for androgenetic alopecia in men because it appeared to be more effective than intralesional dutasteride.

Researchers G. S. Choi et al. also conducted one of the largest and longer-duration studies that examined the effectiveness of dutasteride in treating hair loss. It centered on a multicenter chart review that involved 600 men with androgenetic alopecia to compare the effectiveness of dutasteride versus finasteride. It concluded that dutasteride showed greater effectiveness in improving the anterior hairline and the density of hair on the frontal and vertex areas of the scalp.

Another study by E. A. Olsen et al. compared the effects of dutasteride, finasteride, and placebo in 416 young men experiencing hair loss. Results revealed that dutasteride significantly increased total hair count and hair width after 24 weeks. Finasteride was also effective but not as effective as dutasteride. Those who were in the placebo group demonstrated continuous hair loss progression.

Main Scientific Explanations

The effectiveness of dutasteride in treating hair loss due to androgenetic alopecia has also been explained by researchers. Their studies have specifically explored the mechanism of action behind its effectiveness. The consensus is that it is a DHT blocker that inhibits the production of enzymes needed to convert testosterone into DHT. High levels of DHT are associated with androgenetic alopecia. Take note of the following:

Dutasteride is specifically a selective 5-alpha-reductase inhibitor or a blocker of enzymes involved in steroid metabolism including the formation of DHT from testosterone. DHT is the main androgen or sex hormone in the skin and hair follicles. Excess levels of this hormone lead to the miniaturization of follicles, thinning of strands, and hair fall.

This medication is similar to finasteride and other DHT blockers. It is also different from other hair loss treatment options such as topical minoxidil. Take note that minoxidil works by improving blood circulation and ensuring optimum delivery of nutrition and oxygen in the hair follicles.

Note that finasteride inhibits the type II and III isoforms of 5-alpha-reductase but it is less effective when it comes to inhibiting the type I isoform. Dutasteride inhibits type I and type II isoforms 5-alpha-reductase. These isoforms are more potent when it comes to converting DHT from testosterone.

E. A. Olsen et al. explained that dutasteride is about 3 times more potent than finasteride at inhibiting type II 5-alpha-reductase and 100 times more potent in inhibiting type I. A 5-mg finasteride decreases serum DHT by about 70 percent while a 2.5-mg dutasteride can decrease DHT by more than 90 percent.

Researchers E. A. Olsen et al. concluded that type I and type II 5-alpha-reductase may be important in the pathogenesis and treatment of male pattern hair loss or androgenetic alopecia in men. It specifically suggested the importance of dual 5-alpha-reductase inhibition. This explains why dutasteride is more effective than finasteride.

Pros and Cons of Dutasteride

The aforementioned studies provide evidence and explanations about the effectiveness of Dutasteride in treating hair loss and promoting hair growth. The following are the specific advantages of this medication:

• Effective and Safe in General: The effectiveness of dutasteride in treating hair loss comes from its dual 5-alpha-reductase inhibition mechanism of action that makes it more potent than finasteride in blocking DHT production. There are also established studies that investigated and documented its general safety.

• Accessible and Convenient: Another advantage of this medication is that it comes in a pill or tablet form at a recommended dose of 0.5 milligram. It can be taken once a day with no medical supervision. It can also be purchased as a prescription medication in pharmacies in the United States, Europe, Asia, and South America, among others.

• Reduced Need for Alternatives: The demonstrated effectiveness of dutasteride also means that it may reduce the additional need for alternative treatment options or procedures such as the application of topical formulation including minoxidil or hair restoration procedures such as hair transplant.

• Long-Term Effect and Benefits: Several studies have also noted that the effectiveness of this medication in arresting hair loss and promoting hair growth can persist for up to 5 years or more. Other studies have also documented its long-term safety. This also provides added long-term benefits such as substantial cost savings.

It is still important to underscore the fact that the different causes and types of hair loss warrant different treatment options. The main disadvantage of dutasteride is that it is not a full-spectrum solution. Below are its specific disadvantages:

• Limitation of Effectiveness: One of the biggest disadvantages of dutasteride is that it is a medication with proven effectiveness in treating men with male pattern hair loss. There are limited studies as regards its effectiveness in women with female pattern hair loss. It is also not effective in treating other types of hair loss.

• Notable Adverse Effects: DHT blockers have several side effects. These include a decrease in sex drive, erectile dysfunction, and a decrease in the amount of semen. Some have reported cognitive problems. There are reports that some individuals experience these side effects in extreme cases.

• Need for Additional Studies: It is true that there are studies that have investigated and documented its effectiveness and general safety but researchers have also argued and agreed that more research should be done to investigate and determine with more assurance regarding its longer-term effects.


  • Choi, G.-S., Sim, W.-Y., Kang, H., Huh, C. H., Lee, Y. W., Shantakumar, S., Ho, Y.-F., Oh, E.-J., Duh, M. S., Cheng, W. Y., Bobbili, P., Thompson-Leduc, P., and Ong, G. 2022. “Long-Term Effectiveness and Safety of Dutasteride versus Finasteride in Patients with Male Androgenic Alopecia in South Korea: A Multicentre Chart Review Study.” Annals of Dermatology. 34(5): 349. DOI: 5021/ad.22.027
  • Herz-Ruelas, M. E., Álvarez-Villalobos, N. A., Millán-Alanís, J. M., León-Gutiérrez, H. de, Ocampo-Garza, S. S., Gómez-Flores, M., and Grimalt, R. 2020. “Efficacy of Intralesional and Oral Dutasteride in the Treatment of Androgenetic Alopecia: A Systematic Review.” Skin Appendage Disorders. 6(6): 338-345. DOI: 1159/000510697
  • Olsen, E. A., Hordinsky, M., Whiting, D., Stough, D., Hobbs, S., Ellis, M. L., Wilson, T., and Rittmaster, R. S. 2006. “The Importance of Dual 5α-reductase Inhibition in the Treatment of Male Pattern Hair Loss: Results of a Randomized Placebo-Controlled Study of Dutasteride versus Finasteride. Journal of the American Academy of Dermatology. 55(6): 1014-1023. DOI: 1016/j.jaad.2006.05.007
  • Stough, D. 2007. “Dutasteride Improves Male Pattern Hair Loss in a Randomized Study in Identical Twins. Journal of Cosmetic Dermatology. 6(1): 9-13. DOI: 1111/j.1473-2165.2007.00297.x
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