Benefits of minoxidil therapy outweigh potential side effects of hypertrichosis: A systematic review and meta-analysis

Summary: Abstract Body: Hypertrichosis, characterized by excessive hair growth, is a recognized side effect of minoxidil, a widely used treatment for androgenetic alopecia. Despite concerns about this side effect, many patients continue therapy due to its proven effectiveness in promoting hair regrowth. This study seeks to quantify the prevalence of hypertrichosis associated with low-dose oral and topical minoxidil use. Additionally, we aim to assess the overall trend of patient adherence to minoxidil despite the occurrence of hypertrichosis, to offer a more comprehensive perspective on this issue and provide reassurance to both clinicians and patients. A systematic review and meta-analysis were conducted, incorporating data from 27 studies comprising 4,294 participants. Eligible studies assessed hypertrichosis in patients using low-dose oral (≤5 mg/day) or topical minoxidil for alopecia. Pooled prevalence of hypertrichosis across studies was calculated as well as overall discontinuation rate. Hypertrichosis was observed in 23% of patients (95% CI: 0.14–0.32, I^2 = 98%), with rates varying across formulations and doses. Oral minoxidil demonstrated higher prevalence rates—10% at 0.25 mg, 15% at 1 mg, and 33% at 1.25 mg—compared to topical formulations, which showed rates of 0% at 2% concentration and 2% at 5% concentration. Notably, only 0.49% of patients discontinued treatment due to hypertrichosis. A significant majority of participants (71.7%) were female, suggesting gender-specific concerns about this side effect. Hypertrichosis is a common but generally mild side effect of minoxidil, with minimal impact on adherence. Clinicians should reassure patients that the benefits of minoxidil therapy for alopecia outweigh the potential for excessive hair growth. Maggie I. Weichert¹, Matthew Chen¹, William Guo¹, Nicole Schrock¹, James Briley¹ 1. Dermatology, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, United States. Clinical Research: Epidemiology and Observational Research