Treatment with sublingual minoxidil was safe and associated with increased scalp hair growth in men and women with pattern hair loss, according to findings from a phase 1b clinical trial published in the Journal of the European Academy of Dermatology and Venereology.

According to the study researchers, sublingual minoxidil is expected to reduce the risk for hemodynamic side effects and improve safety compared with oral dosing. To evaluate the sublingual vs oral minoxidil formulation, the investigators randomly assigned 40 men and women (age range, 30-65 years) to either 0.45 mg sublingual minoxidil (n=20) or placebo (n=20) daily for 24 weeks.

A total of 12 patients were subsequently rolled into a 24-week, open-label extension study in which they received 1.35 or 4.05 mg sublingual minoxidil per day. The researchers examined macrophotography and terminal hair count on phototrichogram. The macro photographs were scored on a 7-point rating scale.


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The men in the study had Hamilton Norwood stage 3 vertex to 5, and women had Sinclair stages 2 to 5 hair loss. At the 24-week follow-up period, approximately 45% of patients in the sublingual 0.45 mg minoxidil group experienced improvements in frontal hair density and 55% showed vertex improvement.

In all, 17% of patients who received 1.35 mg sublingual minoxidil in the extension experienced improvements in frontal density, ans 50% had an improvement in vertex hair density. In addition, almost 67% of patients who received the 4.05 mg dose experienced improvements in frontal and vertex hair density.

In the 0.45 mg dose group, phototrichograms showed a mean increase in terminal hair count/cm2 of 4 for the frontal and 9 for the vertex scalp. Also, treatment with the 1.35 mg dose resulted in a mean increased terminal hair count/cm2 of 10 and 26, and the 4.05 mg dose led to a mean increase terminal hair count/cm2 of 38 for the frontal and 88 for the vertex scalp.

The researchers explained that the difference in mean hair count 0 was statistically significant for the frontal and vertex scalp at all doses compared with placebo, with an exception noted for the 0.45 mg dose over the vertex. This lack of difference at the 0.45 mg dose on the vertex scalp was due to 1 patient in the placebo group who experienced an increase in vertex scalp hair density by 76 hair per cm2, which the investigators noted was unexpected.

At 30 minutes following the initial sublingual dose, the mean peak minoxidil plasma concentration was 1.62 ng/mL but ranged from 0.3 to 5.3 ng/mL. The medication was undetectable in the plasma after 24 hours. According to the investigators, this was considered “more than an order of magnitude below the plasma concentration threshold” of 20 ng/mL for the occurrence of any hemodynamic event.

The researchers wrote that “further studies with larger patient cohorts are warranted to determine the optimal dose of” sublingual minoxidil and to compare the relative efficacy of sublingual vs oral formulations of the drug.

Disclosure: Several study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

Reference

Bokhari L, Jones LN, Sinclair RD. Sublingual minoxidil for the treatment of male and female pattern hair loss: a randomized, double-blind, placebo-controlled, phase 1B clinical trial. J Eur Acad Dermatol Venereol. Published online August 22, 2021. doi:10.1111/jdv.17623