The Hidden Price of Vanity: What Finasteride Can Do to Your Brain

Finasteride, a medication used to treat baldness, can cause depression, anxiety, and even suicidal thoughts, effects that took almost 20 years to be recognized. Recent studies analyzed millions of medical records and confirmed the increased risk of these symptoms among users, even after stopping treatment. The delay was due to lapses in oversight by companies and regulatory agencies. Experts argue that medications used solely for aesthetic reasons should be evaluated much more rigorously, as the risk may outweigh the benefit.

Finasteride is a well-known medication widely prescribed worldwide to treat androgenetic alopecia, male pattern baldness. Despite being seen as an effective aesthetic solution, worrying reports have emerged for years about its potential side effects on the brain and mental health.

This study systematically gathered and analyzed all available scientific evidence to understand whether finasteride can, in fact, cause problems such as depression, anxiety, and even suicidal thoughts, and why this information took so long to be recognized.

Since the early 2000s, some studies have pointed to a possible link between finasteride use and the onset of depressive symptoms. In 2002, researchers began noticing that some men experienced significant changes in mood and anxiety during or after treatment.

Even so, these reactions were initially treated as rare or isolated, and the drug continued to be widely prescribed without major restrictions.

It was only between 2017 and 2023 that more consistent and comprehensive analyses began to emerge.

Four different studies used adverse event reporting systems, databases in which doctors and patients record negative reactions after medication use. Four other studies used data mining in large health registries, analyzing millions of medical records to identify risk patterns.

The results were clear: there was a statistically significant increase in cases of depression, anxiety, and suicidal behavior among people using finasteride.

Finasteride works by blocking an enzyme called 5-alpha-reductase, which is responsible for converting testosterone into dihydrotestosterone (DHT), a hormone involved in hair loss. However, this same enzyme also acts in the brain, where it helps produce substances known as neurosteroids, which regulate mood, anxiety, and feelings of well-being.

When finasteride blocks this enzyme, the production of these neurosteroids decreases, which can cause an imbalance in the systems that control emotions and stress responses. This reduction affects, for example, GABA and serotonin receptors, neurotransmitters essential for emotional regulation.

Over time, this imbalance can lead to symptoms of depression, anxiety, loss of pleasure, and, in more severe cases, suicidal thoughts. In some people, these effects persist even after stopping treatment, suggesting that finasteride may cause lasting changes in brain chemistry..

Not everyone who uses finasteride develops symptoms such as depression or anxiety, and this is due to a combination of biological and individual factors. Research suggests that genetic differences may influence how each organism reacts to the reduction of neurosteroids in the brain.

Some people have variations in genes that control the production of neurotransmitters such as serotonin and dopamine, making them more vulnerable to hormonal changes. Furthermore, personal mental health history and previous sex hormone levels can also increase the risk.

External factors, such as chronic stress, sleep deprivation, and traumatic experiences, can exacerbate these effects. In short, the interplay between genetics, hormones, and the environment explains why finasteride can be well tolerated by many but cause serious mood disorders in others.

These findings indicate that the risk may have been underestimated for about two decades. During that time, millions of people used the drug, and estimates suggest that hundreds of thousands may have developed depression related to their use, and hundreds may have died by suicide.

This twenty-year delay in properly recognizing and investigating the problem allowed a large number of people to be exposed to serious risks without proper information.

The study's analysis highlights that the delay is not only due to the complexity of the effects, but also to significant failures on three fronts: the pharmaceutical industry, regulatory agencies, and the scientific system.

First, the finasteride manufacturer failed to conduct or publish basic follow-up studies, called pharmacovigilance studies, which are necessary to detect adverse effects after the drug is released onto the market. Such studies are simple to conduct with data available in medical records, but they were neglected.

Second, regulatory agencies (such as the Food and Drug Administration and others around the world) also failed to require these studies. This means that post-marketing monitoring, an essential step in drug safety, was not properly enforced. 

Finally, the study suggests that there was cultural and scientific resistance to recognizing the adverse effects associated with a drug used for cosmetic purposes. Because it was seen as an "appearance treatment," the potential for mental harm did not receive the same attention as it would for a life-saving drug.

The authors argue that, based on the precautionary principle, that is, "when in doubt, prioritize patient safety", any drug used for non-life-saving purposes must have extremely rigorous safety standards. In the case of finasteride, used to treat baldness, the benefit is aesthetic, while the potential harm involves serious mental health risks, including suicide. Therefore, the balance between benefit and risk is disproportionate.

The study proposes an important change in drug approval and monitoring policies: regulatory agencies should require, prior to approval, a formal commitment that companies will conduct and publish ongoing post-market safety studies. Furthermore, failure to comply with this obligation should have serious regulatory consequences.

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Failing Public Health Again? Analytical Review of Depression and Suicidality From Finasteride

Mayer Brezis

J Clin Psychiatry 2025;86(4):25nr15862

DOI: 10.4088/JCP.25nr15862

Abstract: 

Finasteride, widely prescribed for androgenetic alopecia, has long been suspected of causing severe neuropsychiatric reactions, including depression, anxiety, and suicidality, even after the drug is discontinued. This study systematically reviews evidence that supports this suspicion and analyzes the reasons for this delayed recognition. Concerns about depression from finasteride were raised in several studies as early as 2002. Between the years 2017 and 2023, 4 independent analyses of adverse event reporting systems and 4 studies using data mining of healthcare records indicated a significant increase in the risk for depression, anxiety, and/or suicidal behavior with the use of finasteride. There has been, therefore, a two-decade delay in the realization of the incidences and the gravity of neuropsychiatric effects, allowing harm from a medicine prescribed for a cosmetic indication of hair loss. Over 20 years worldwide, hundreds of thousands may have endured depression, and hundreds may have died by suicide. According to the precautionary principle, such a risk from a cosmetic medication suggests a benefit-to-harm balance that justifies action to protect the public, and the burden of proving that the intervention is not harmful falls on manufacturers. The long delay in recognizing the risks associated with finasteride exposure includes the manufacturer’s failure to perform and publish simple pharmacovigilance studies using database analyses and regulators’ failure to request such studies from the manufacturer or to perform them. Current evidence shows that finasteride use can cause depression and suicidality. A historical literature review discloses gaps between research evidence and regulatory steps. The lesson is that before approving a medication for the market, regulators should require manufacturers to commit to performing and disclosing ongoing postapproval analytical studies, and this requirement needs to be enforced.