ORAL AND TOPICAL FINASTERIDE IN THE TREATMENT OF MALE ANDROGENETIC ALOPECIA – NARRATIVE REVIEW

Background Androgenetic alopecia is the most common form of progressive non scarring hair loss in men and is driven by dihydrotestosterone mediated miniaturization of hair follicles. The condition may negatively affect psychological well being and quality of life. Finasteride, a 5 alpha reductase inhibitor, is a key pharmacologic therapy. Aims To evaluate the mechanism of action, metabolism, efficacy, and safety of finasteride in male androgenetic alopecia, with comparison of oral and topical formulations, assessment of systemic exposure and DHT reduction, and review of adverse effects, alternative FDA approved treatments, combination strategies, and broader clinical relevance. Methods A narrative review was conducted using PubMed and Google Scholar for English language studies published between 2015 and 2026. Fifty one references were included. Priority was given to randomized controlled trials, systematic reviews, meta analyses, pharmacokinetic studies, and pharmacovigilance reports. Data were synthesized descriptively without formal quality assessment or meta analytic pooling. Results Finasteride inhibits type II and III 5 alpha reductase, lowering scalp and serum DHT levels and stabilizing hair growth. Oral finasteride 1 mg daily significantly improved hair count and density, with reported increases of 18.37 hairs per cm² in comparative analyses. Topical 0.25 percent formulations showed comparable efficacy after 24 weeks with markedly lower systemic exposure and smaller reductions in serum DHT. Oral therapy has been associated with sexual adverse effects and reported neuropsychiatric symptoms. Post finasteride syndrome remains controversial, and pharmacovigilance signals regarding depression and suicidal ideation require cautious interpretation. Combination regimens, particularly with topical minoxidil, demonstrated enhanced outcomes in selected studies. Finasteride is also approved for benign prostatic hyperplasia and has shown a reduction in overall prostate cancer incidence in long term trials. Conclusions Finasteride is a major therapeutic option for male androgenetic alopecia. Oral therapy provides robust efficacy but greater systemic exposure, whereas topical formulations offer similar hair growth outcomes with reduced systemic DHT suppression. Given the narrative design and heterogeneity of available data, conclusions should be interpreted with caution.