This randomized, double-blind, placebo-controlled clinical trial included 90 men with androgenetic alopecia. The results showed that daily oral minoxidil, 5 mg, was well tolerated but did not show superiority over topical minoxidil, 5%, after 24 weeks of treatment.
This means that low-dose oral minoxidil (5 mg per day) had similar efficacy to topical minoxidil, 5%, for men with androgenetic alopecia and may be an option for patients who prefer oral therapy or are intolerant to topical treatment.
There has been growing interest in low-dose oral minoxidil for the treatment of androgenetic alopecia (AGA). However, the efficacy of oral minoxidil for male AGA has not yet been evaluated in comparative therapeutic trials.
This randomized, double-blind, placebo-controlled trial was conducted at a specialized clinic in Brazil. Eligible men with AGA, aged 18 to 55, classified using the Norwood-Hamilton scale as 3V, 4V, or 5V, were included and randomized. Data were collected from January to December 2021 and analyzed from September 2022 to February 2023.
Participants were randomly assigned 1:1 into two groups: oral minoxidil, 5 mg, daily placebo topical solution; or 1 ml of topical minoxidil 5%, twice daily, and oral placebo for 24 weeks.
The primary outcome was the change in terminal hair density in the frontal and vertex scalp regions. Secondary outcomes included the change in total hair density and photographic assessment.
Of the 90 participants, 68 completed the study, with an average (SD) age of 36.6 (7.8) years. A total of 33 participants were enrolled in the oral minoxidil group and 35 in the topical treatment group.
Both groups were homogeneous in terms of demographics and AGA severity. In the frontal area, the mean change from baseline to week 24 between the groups was 3.1 hairs per cm² (95% CI, −18.2 to 21.5; P = 0.27) for terminal hair density and 2.6 hairs per cm² (95% CI, −10.3 to 15.8; P = 0.32) for total hair density.
In the vertex area, the mean change from baseline to week 24 was 23.4 hairs per cm² (95% CI, −0.3 to 43.0; P = 0.09) for terminal density and 5.5 hairs per cm² (95% CI, −12.5 to 23.5; P = 0.32) for total hair density.
According to the photographic analysis, oral minoxidil was superior to topical minoxidil at the vertex (24%; 95% CI, 0 to 48; P = 0.04), but not in the frontal scalp (12%; 95% CI, −12 to 36; P = 0.24).
The most common adverse effects in the oral minoxidil group were hypertrichosis (22 of 45 [49%]) and headache (6 of 45 [14%]).
In this study, 5 mg oral minoxidil once daily for 24 weeks did not demonstrate superiority over topical minoxidil, 5%, twice daily in men with androgenetic alopecia.
Trial Registration: Brazilian Clinical Trials Registry Identifier: RBR-252w9r
