A randomized, double-blind, placebo-controlled clinical trial found that oral bicalutamide 25 mg daily combined with oral minoxidil 1 mg did not improve outcomes for female pattern hair loss compared with minoxidil alone after 24 weeks of treatment.
In the study, published in JAAD International, 74 female participants with female pattern hair loss (FPHL) (Sinclair scale II to IV) were randomly assigned to receive either bicalutamide 25 mg plus minoxidil 1 mg daily or placebo plus minoxidil 1 mg daily.
“There was a mean increase of 18.1 hairs/cm² in the bicalutamide-minoxidil group and 21.5 hairs/cm² in the minoxidil group (P = .86),” the authors reported. “According to the global consensus analysis of clinical photographs, there was no difference in clinical improvement between the groups (P = .78).”
The trial was conducted at a single center in Salvador, Brazil, from August 2022 to July 2023, and evaluated efficacy, safety, and tolerability of bicalutamide for FPHL. The primary endpoint was change in hair density, measured via trichoscopic image analysis of a standardized 1 cm² tattooed area in the central parietal region, using a validated semiautomated method with ImageJ software.
The 74 participants, aged 21 to 59 years, were randomized 1:1. Sixty-four (86.5%) completed the 24-week trial. Baseline and week-24 assessments included standardized clinical photographs, hair shedding scores (Sinclair scale), and the Women’s Androgenetic Alopecia Quality of Life Questionnaire (WAA-QoL).
Blinded dermatologists evaluated clinical photographs using a 7-point Global Improvement Scale. No statistically significant difference was observed between groups.
However, a greater reduction in hair shedding scores was observed in the bicalutamide-minoxidil group compared with the minoxidil-only group (P = .03). At baseline, 86% of patients in the combination group and 84% in the monotherapy group had high-grade shedding (grades IV to VI); these rates fell to 22% and 50%, respectively, by week 24.
Both groups showed significant improvement in WAA-QoL scores, with no statistically significant difference between them (P = .63).
Adverse effects were generally mild and similar between groups. Facial hypertrichosis occurred less frequently in the bicalutamide-minoxidil group than in the minoxidil-only group (49% vs 73%, P = .03). Transient hair shedding during the first month was also lower in the combination group (16% vs 38%, P = .04). There were no cases of elevated liver enzymes in the bicalutamide group; two participants in the minoxidil-only group developed increased transaminases and were withdrawn from the study.
Other reported adverse effects included headache, edema, menstrual irregularities, decreased libido, and gastrointestinal symptoms, with no significant between-group differences.
Despite previous retrospective studies suggesting a potential benefit of bicalutamide for FPHL, this randomized trial did not demonstrate superiority of the bicalutamide-minoxidil combination over minoxidil alone at 24 weeks.
“The role of the androgen factor in the physiopathology of FPHL in normoandrogenic women is still uncertain,” the authors noted. “Further clinical trials with other antiandrogens, different doses of bicalutamide, and longer follow-up are necessary to establish the potential benefit of this kind of treatment.”
Limitations of the study included its single-center design and the relatively short 24-week follow-up period. No conflicts of interest were reported.
