Efficacy and safety of oral minoxidil versus topical solution in androgenetic alopecia: a meta-analysis of randomized clinical trials

The benefits and potential risks of oral minoxidil therapy versus topical minoxidil therapy in patients with androgenetic alopecia (AGA) are controversial. We systematically searched PubMed, Embase, and Cochrane for randomized clinical trials (RCTs) comparing the use of oral minoxidil and minoxidil topical solution in patients with AGA. Statistical analyses were performed using R Studio 4.3.2. Standard mean difference (SMD) and risk ratio (RR) with 95% confidence intervals (CI) were pooled across trials. This meta-analysis included four RCTs reporting data on 279 patients. Follow-up ranged from 24 to 39 weeks. There were no differences in hair density (SMD 0.02; 95% CI −0.25 to 0.29; P = 0.88; I² = 0%) or hair diameter (SMD −0.25; 95% CI −0.75 to 0.26; P = 0.34; I² = 36%). The incidence of hypertrichosis was statistically significantly higher in the oral minoxidil group when compared to the topical minoxidil group (RR 2.01; 95% CI 1.18–3.41; P = 0.01; I² = 0%). There was no statistically significant difference between groups for the incidence of hypotension (RR 2.42; 95% CI 0.26–22.46; P = 0.44; I² = 0%). In patients with AGA, oral minoxidil and minoxidil topical solution have similar efficacy and safety, with equivalent improvements in hair density, hair diameter, and incidence of adverse events, such as hypotension.