Relative Efficacy of Minoxidil and the 5-α Reductase Inhibitors in Androgenetic Alopecia Treatment of Male Patients

IMPORTANCE: There are knowledge gaps regarding the relative efficacy of 3 commonly used drugs for androgenetic alopecia (AGA), namely, minoxidil and the two 5-α reductase inhibitors dutasteride and finasteride. OBJECTIVE: To examine the relative efficacy of any dose and administration route of minoxidil, dutasteride, and finasteride for the treatment of male AGA. DATA SOURCES: Systematic searches were performed in PubMed on March 5, 2021, without date restrictions. STUDY SELECTION: Eligible studies included those that investigated monotherapy with any dose and administration route of minoxidil, dutasteride, and finasteride. DATA EXTRACTION AND SYNTHESIS: Data on the mean (SD) difference and sample size were used for the bayesian network meta-analyses. League tables and surface under the cumulative ranking curve values were used to examine the relative efficacy of the interventions. MAIN OUTCOMES AND MEASURES: Study end points were change in total and terminal hair count after 24 and 48 weeks of therapy. The 4 end points were quantified in hairs per square centimeters. RESULTS: The PubMed search yielded 848 records; after the 2 stages of screening, 23 studies were eligible for quantitative analyses. Mean (SD) age of patients ranged from 22.8 (3.3) years to 41.8 (12.3) years. The greatest increase in total hair count at 24 weeks (ie, first end point) was with 0.5 mg/d of dutasteride, which was significantly more efficacious than 1 mg/d of finasteride (mean difference, 7.1 hairs/cm2; 95% CI, 5.1-9.3 hairs/cm2) and minoxidil (0.25 mg/d [mean difference, 23.7 hairs/cm2; 95% CI, 9.5-38.0 hairs/cm2], 5 mg/d [mean difference, 15.0 hairs/cm2; 95% CI, 3.9-26.1 hairs/cm2], and 2% solution [mean difference, 8.5 hairs/cm2; 95% CI, 4.8-12.3 hairs/cm2]). The greatest increase in terminal hair count at 24 weeks (ie, second end point) was with 5 mg/d of minoxidil, which was significantly more efficacious than the 0.25-mg/d dose (mean difference, 43.6 hairs/cm2; 95% CI, 29.7-57.7 hairs/cm2) and its topical forms (in 2% [mean difference, 29.3 hairs/cm2; 95% CI, 21.1-37.5 hairs/cm2] and 5% [mean difference, 29.8 hairs/cm2; 95% CI, 19.7-39.8 hairs/cm2]); 5 mg/d of minoxidil was significantly more efficacious than 1 mg/d of finasteride (mean difference, 10.4 hairs/cm2; 95% CI, 2.2-18.6 hairs/cm2). The greatest increase in total hair count at 48 weeks (ie, third end point) was with 5 mg/d of finasteride, which was significantly more efficacious than 2% topical minoxidil (mean difference, 20.7 hairs/cm2; 95% CI, 9.5-31.9 hairs/cm2). The greatest increase in terminal hair count at 48 weeks (ie, fourth end point) was with 1 mg/d of finasteride, which was significantly more effective than topical minoxidil (in 2% [mean difference, 32.1 hairs/cm2; 95% CI, 23.9-40.3 hairs/cm2] and 5% [mean difference, 26.2 hairs/cm2; 95% CI, 16.2-36.2 hairs/cm2]). CONCLUSIONS AND RELEVANCE: As efficacy data from head-to-head trials accumulate, there could be a better sense of the relative efficacy of the different doses of the 5-α reductase inhibitors and minoxidil. The findings of this meta-analysis contribute to the comparative effectiveness literature for AGA therapies with regard to the compared interventions.