Minoxidil Beyond Hair: A Comprehensive Review of Its Effects on Nail Growth.

Minoxidil is a well-established treatment for hair loss, known for its vasodilatory properties and effects on dermal papilla cells. Recently, interest has emerged regarding its potential role in promoting nail growth, both in healthy individuals and in those with nail dystrophies. The objective of this review was to synthesize and critically analyze the available evidence on the effects of topical and oral minoxidil on nail growth, including proposed mechanisms of action, clinical outcomes, and safety. A narrative literature review was conducted using studies published in indexed journals that evaluated the pharmacological effects of minoxidil on the nail unit. Mechanistic data were extracted from in vitro and in vivo models, while clinical results were compiled from pilot studies, case reports, and trials evaluating nail growth in both healthy and pathologic conditions. Proposed mechanisms include vasodilation, increased VEGF expression, and hypothesized involvement of pro-growth pathways (e.g., Wnt/β-catenin), largely extrapolated from hair follicle biology; direct nail-matrix-specific mechanistic evidence remains limited. Clinical studies with 5% topical minoxidil have shown increases in nail growth rate ranging from 13% to 19% over 28 days, while oral minoxidil (2.5 mg) resulted in an approximately 50% increase in nail growth speed in small studies. Evidence also suggests improvements in nail strength and appearance. Adverse effects were minimal, with no significant changes in blood pressure and only modest increases in heart rate with oral formulations. Although evidence remains limited, preliminary findings suggest a potential role for minoxidil in enhancing nail growth, particularly in cases of slowed growth or nail dystrophy. More robust, large-scale studies are needed to confirm efficacy, determine optimal formulations, and establish long-term safety. Given its accessibility and tolerability, minoxidil may represent a promising off-label adjunct for nail growth modulation.