Finasteride, a 5α-reductase inhibitor widely used for male androgenetic alopecia and benign prostatic hyperplasia has gained popularity, especially among patients seeking hair restoration via medical therapy or transplantation. While its efficacy in reducing dihydrotestosterone (DHT) levels and slowing hair follicle miniaturization is well established, growing attention focuses on possible neuropsychiatric side effects associated with its use. Understanding such risks is particularly important for patients considering long-term therapy and for clinicians advising them especially in the setting of hair transplantation, where expectations and psychological vulnerability may be heightened.

Epidemiological and Clinical Evidence

Increased depression, anxiety, suicidal ideation in some users

A systematic review and meta-analysis pooling data from studies comparing finasteride users vs non-users found a significantly higher odds of depressive symptoms in the finasteride group.

Moreover, a pharmacovigilance study of post-marketing reports (spontaneous adverse event reporting) identified a disproportionality signal for psychological adverse events and suicidality in patients treated with finasteride especially younger men (aged ≤ 44) using it for hair loss.

A large population-based case-control study comparing users treated for benign prostatic hyperplasia (BPH) and androgenetic alopecia (AGA) with matched controls found a modest but statistically significant increased risk of depression and anxiety among AGA patients using finasteride at 1 mg daily.

Mechanism: How Might Finasteride Affect the Brain?

Finasteride inhibits 5α-reductase, a key enzyme not only in converting testosterone to DHT, but also in the biosynthesis of several neuroactive steroids (neurosteroids) such as Allopregnanolone. These neurosteroids modulate GABA_A receptors and contribute to the regulation of mood, anxiety, and stress responses. Suppression of neurosteroid production may impair normal inhibitory neurotransmission, potentially leading to mood instability and heightened susceptibility to depressive or anxious symptoms.

Challenges and Limitations

• Causality vs association: Many of the data come from observational studies or spontaneous reporting systems; while they show correlation, establishing a definitive causal link remains difficult. Confounding factors for example, the psychological burden associated with hair loss itself may contribute.
• Psychological vulnerability and baseline risk: Many individuals seeking hair loss treatment may already suffer from body-image distress, low self-esteem, or subclinical psychological issues which could predispose them to mood changes regardless of therapy.
• Underreporting and reporting bias: Spontaneous reporting relies on patients and clinicians recognizing and attributing mental health changes to finasteride.

Clinical Implications

Pre-treatment screening: Before prescribing finasteride particularly for hair loss inquire about personal or family history of mood disorders, depression, suicidal ideation, or other psychiatric vulnerability.

Monitoring: Follow up periodically (e.g., every 3–6 months) on psychological well-being, mood, sexual function, and overall quality of life. Encourage patients to report any symptoms promptly.

Alternative approaches: In patients with preexisting psychological vulnerability or those willing to avoid pharmacological risk consider alternative treatments (e.g., hair transplantation alone, non-pharmacological strategies, topical therapies when appropriate, though these too are not risk-free) and/or involve psychological support or counselling to manage expectations.

Conclusion

Finasteride remains an effective and widely used option for male pattern hair loss but it is not psychologically inert. Over decades of use, accumulating clinical, epidemiological, and preclinical evidence points to a small but non-negligible risk of mood disturbances, depression, anxiety, and in a subset of users, even suicidal ideation or persistent neuropsychiatric symptoms.

For surgeons, and patients recognizing these risks, transparently discussing them, and monitoring psychological health should be integral parts of care. In selected cases, non-pharmacological alternatives or psychological support may be more appropriate than automatic initiation of finasteride. Continued research is needed to clarify risk factors, mechanisms, and long-term outcomes.