Does topical minoxidil at concentrations higher than 5% provide additional clinical benefit?

Minoxidil solution is used for the treatment of androgenetic alopecia (AGA). Minoxidil 5% solution has been shown to have superior efficacy to minoxidil 2% solution, it is unknown whether concentrations of minoxidil > 5% provide additional clinical benefit. We performed a review of the literature to examine the evidence on the efficacy and safety of higher concentrations of minoxidil in AGA. A search of the PubMed database was performed using the keywords 'minoxidil', 'androgenic alopecia' and 'pattern hair loss'. Relevant articles, including clinical trials, other clinical studies, case series and case reports published in English were considered for review. In addition, relevant references from the bibliography section of the retrieved articles were also reviewed.