Pharmacokinetics and Safety of 1 mg Oral Minoxidil Tablets in Healthy Female Volunteers: A Phase I Randomized Crossover Clinical Trial

ABSTRACT Background Topical minoxidil is a first‐line treatment for female androgenetic alopecia (FAGA); however, its twice‐daily application, potential for scalp irritation and impact on hair texture can compromise adherence. Although low‐dose oral minoxidil has emerged as a promising alternative, standardized formulations with well‐characterized pharmacokinetic (PK) and safety profiles remain lacking. Objectives To evaluate the PK profile and safety of the 1 mg oral minoxidil tablet following single and multiple dosing, and compare it to a 2% minoxidil topical solution. Methods A phase I, open‐label, randomized, two‐sequence, two‐period clinical trial was conducted (NCT06015516). Fourteen healthy adult women were assigned to receive both the oral and topical solutions under fasting conditions for 5 consecutive days each, with a 7‐day washout period. Serial blood samples were collected after single‐ and multiple‐dose administration for PK analysis. Adverse events (AEs), laboratory tests, vital signs and ECG were monitored. Results Fourteen women completed the trial. The 1 mg oral minoxidil tablet showed consistent PK following both single and multiple dosing, with markedly higher plasma concentrations than the 2% minoxidil topical solution. Seven AEs were reported, one of which was identified as related to the topical drug. No serious AEs or clinically relevant changes in laboratory tests, ECG or vital signs were observed with either formulation. Conclusions The 1 mg oral minoxidil tablet exhibits a predictable and stable PK profile, with greater systemic bioavailability than the 2% minoxidil solution, and a favourable tolerability profile. These findings support the continued clinical development of this oral formulation. Trial Registration: ClinicalTrials.gov (NCT06015516)