Injectable Minoxidil for Hair Loss Disorders: A Systematic Review

BACKGROUND: Minoxidil is a frequently prescribed medication for hair loss. Although topical and oral minoxidil is widely established for treating hair loss by dermatologists, there is a lack of a comprehensive review regarding the use of injectable minoxidil. OBJECTIVE: This paper aims to elucidate the clinical efficacy and safety of injectable minoxidil in treating the specific hair loss diagnoses of androgenetic alopecia and alopecia areata. This review performs individual and comparative analyses of both disorders in populations of all age groups and genders. RESULTS: Two-hundred eighty-six (286) articles originated from both screens. Among these, 11 articles with 19,192 patients were included, encompassing 5 randomized controlled trials (RCTs), 1 uncontrolled clinical trial (CT), 2 retrospective studies, and 3 case reports. Studies on androgenetic alopecia reported significant improvement in hair growth (P>0.05) after receiving treatment with injectable minoxidil. In comparison, studies on alopecia areata demonstrated case-by-case outcomes, with two out of four studies reporting significant improvement. The primary side effects reported were hypotension and pain. Insufficient high-quality studies are available to analyze the use of injectable minoxidil for scarring hair loss. CONCLUSIONS: This systematic review demonstrates injectable minoxidil is an efficacious and safe treatment for androgenetic alopecia, with variable efficacy and safety for treating alopecia areata. Injectable minoxidil is a promising primary and adjunctive therapy for treating androgenetic alopecia clinically. Further translational research should explore how the pharmacokinetic and bioavailability of injectable minoxidil translates to clinical efficacy to establish the optimal dosing. J Drugs Dermatol. 2024;23(12):1084-1088. doi:10.36849/JDD.8301.