Low-Dose Oral Minoxidil for Alopecia: A Comprehensive Review

Low-dose oral minoxidil (LDOM) has demonstrated a promising safety and efficacy profile in the treatment of various hair disorders, including male androgenetic alopecia (AGA) and female-pattern hair loss (FPHL); however, it lacks FDA approval. The usual LDOM starting dose for male AGA is 1-5 mg/day, depending on physician preference and the patient's condition. For FPHL, it is 0.5-1 mg/day. The maximum dose is generally 5 mg/day. If patients respond well without major side effects, the dose may be gradually increased since the LDOM's efficacy appears to be dose-dependent. Patients may use LDOM long term if the treatment outcome is satisfactory. The common side effects of LDOM are hypertrichosis and cardiovascular symptoms. Females are more prone to hypertrichosis than males. The side effects of LDOM can be categorized as (a) dose-dependent type A side effects (hypertrichosis and cardiovascular symptoms) and (b) idiosyncratic type B side effects (pericardial effusion). Minoxidil acts via multiple pathways. Although minoxidil has a relatively short half-life of around 4 h, its hypotensive effect may last approximately 72 h. Effective treatments for alopecia are limited. Therefore, LDOM could be an important addition to the available therapies for managing some hair disorders, including AGA.