The inhibition of 5α-R represents a paradigmatic example of how a drug originally designed for urological and dermatological purposes may have repercussions for neurobiology and mental health. The available evidence suggests that while most patients tolerate finasteride and dutasteride adequately, there is a vulnerable subgroup in which a reduction in neurosteroids—particularly allopregnanolone—may contribute to the development of affective and cognitive symptoms. Epidemiological data are heterogeneous and limited by methodological biases, yet the biological plausibility of this association is well supported. This warrants heightened caution, especially when the indication is cosmetic, and underscores the need to strengthen patient counseling within a shared decision-making framework.
Rodriguez-Cerdeira, C. Systematic Review: 5α-Reductase Isoenzymes: From Neurosteroid Biosynthesis to Neuropsychiatric Outcomes, February 2, 2026. https://doi.org/10.3390/neurosci7010020 [NeuroSci]