Characteristics of Hypertrichosis Induced by 24-week Low-dose (5 mg Daily) Oral Minoxidil in Male Pattern Hair Loss Treatment.

Objective: Oral minoxidil (OM) is approved by the US Food and Drug Administration for the treatment of hypertension. It has also been off-label used increasingly for hair disorders like androgenetic alopecia (AGA). Hypertrichosis is known as the most commonly found adverse effect of oral minoxidil (LDOM) at low dose of 0.25-5 mg. This study aims to describe the characteristics of hypertrichosis induced by 5 mg daily oral low-dose minoxidil for 24 weeks in male AGA treatment. Materials and Methods: This prospective study included 30 male AGA patients who received treatment with 5 mg daily oral low-dose minoxidil. The modified Ferriman-Gallwey scoring system was used for the assessment of hypertrichosis by physicians in the forearm area at baseline, 12 and 24 weeks. The Dermatology Life Quality Index was applied to assess the impact of hypertrichosis on quality of life. Patients were divided into two age groups: under 41 and 41 or older. Results: Hypertrichosis was prevalent in 93% of patients, especially the younger group with a higher incidence and variation of severity. Most patients indicated a general tolerance with minimal impact on their quality of life. Notably, hypertrichosis seldom led to drug discontinuation despite a widespread occurrence. Conclusion: The 24-week treatment of low-dose 5 mg daily OM induces a high prevalence of hypertrichosis in male AGA patients. Further study is recommended for long-term implications and safety profiles of low-dose oral minoxidil.