Background: Previous studies have proven the efficacy and safety of 0.01% and 0.03% bimatoprost for the treatment of eyebrow hypotrichosis; however, there is no comparison study between both concentrations.

Aims: To compare the efficacy and safety between 0.01% and 0.03% bimatoprost for the treatment of eyebrow hypotrichosis.

Patients/methods: This prospective, randomized, double-blind, split-face clinical study was conducted in 30 patients with eyebrow hypotrichosis. Each side of eyebrow of individual patients was randomly assigned for 0.01% and 0.03% bimatoprost, applied on each eyebrow once daily. Eyebrow density, diameter, the Global Eyebrow Assessment scale, 7-point rating scale, and patient satisfaction were evaluated. Side effects were also recorded.

Results: Both 0.01% and 0.03% bimatoprost significantly improved eyebrow density and diameter (P < .05), although there were no statistically significant differences in changes in eyebrow density and diameter from baseline between both concentrations (P = .96 and .84, respectively). Additionally, patients significantly preferred 0.03% bimatoprost in terms of clinical improvement and satisfaction (P = .04 and .003, respectively).

Conclusions: Both 0.01% and 0.03% bimatoprost are effective and safe for the treatment of eyebrow hypotrichosis. Bimatoprost 0.03% is superior to its 0.01% counterpart, albeit without statistical significance.