Finasteride and Suicide: Two Decades Of Missed Warnings About Popular Hair Loss Drug

JERUSALEM — For over two decades, millions of men worldwide have taken finasteride to combat hair loss, seeking a solution to balding that seemed simple and safe. But mounting evidence shows this cosmetic medication can cause severe depression and suicidality in some users. Both the drugmaker and federal regulators failed to act on early warning signals and did not require timely analytical studies

A new analytical review published in the Journal of Clinical Psychiatry reveals a troubling timeline. According to the review, concerns about depression from finasteride surfaced as early as 2002, yet it took until 2011 for the FDA to acknowledge depression as a side effect, 2022 to add suicidal ideation as an adverse reaction (though not as a formal warning), and 2025 for European regulators to acknowledge the drug can cause suicide. During this two-decade lag, the study estimates hundreds of thousands may have suffered depression, and hundreds may have died by suicide; elsewhere the author speculates the toll could reach the low thousands.

“This paper is dedicated to the memory of a healthy person who started taking finasteride several years ago, ‘just’ to improve his hair,” writes study author Dr. Mayer Brezis. “Within a week, he developed severe neuropsychiatric symptoms that did not abate after stopping the drug. Treatment attempts by the best specialists did not help, and a few months later, he died by suicide.”

Finasteride works by blocking an enzyme that converts testosterone. The FDA approved it in 1997 for treating male pattern baldness, known medically as androgenetic alopecia. The drug became popular among men looking to keep their hair, prescribed for what doctors considered a purely cosmetic concern.

What the Research Shows: Eight Studies Link Finasteride to Mental Health Problems

Dr. Brezis, from the Hadassah-Hebrew University Medical Center in Jerusalem, conducted a systematic review of postmarketing studies published between 2017 and 2024. He identified eight independent analyses that all pointed in the same direction: finasteride significantly increases the risk of depression, anxiety, and suicidal behavior.

Four of these studies used disproportionality analysis, a method that examines how often adverse events are reported for finasteride compared to other medications in databases like the FDA Adverse Event Reporting System. The other four studies mined large healthcare record databases, comparing health outcomes for people who took finasteride against similar individuals who didn’t.

Different studies found finasteride users experienced depression at rates 60% to 90% higher than non-users. For self-harm, the increased risk ranged from 90% to more than three times higher. Suicide ideation showed more than a four-fold increase in one analysis. In safety reporting databases, the reporting odds for completed suicides were five to nine times higher for finasteride than comparator drugs.

One French study found particularly alarming results for people with a prior history of mood disorders. Their risk of self-harm was more than three times higher, and suicide risk was nearly three times higher when taking finasteride.

Studies included data from multiple countries and healthcare systems. Ontario health records from 2003 to 2013 showed higher rates of both self-harm and depression. Swedish healthcare data from 2005 to 2018 confirmed increased depression and cognitive dysfunction. French records from 2012 to 2016 revealed elevated self-harm and suicide rates. Israeli data from 2019 to 2020 documented significantly higher anxiety and depression.

“Assuming a null hypothesis, that finasteride does not affect mood, and a 50% chance of one result against this hypothesis, the probability of getting all eight studies concluding against the null hypothesis by chance is 0.0039,” Brezis writes. Put simply, finding all eight studies pointing in the same direction would be extremely unlikely if finasteride had no effect on mood. However, this statistical pattern doesn’t tell us how large the risk is for any individual person.

Why Finasteride Affects Your Brain: The Science Behind the Side Effects

The connection between finasteride and mood disorders isn’t just statistical. There’s a biological explanation. Finasteride inhibits an enzyme called 5α-reductase, which affects the production of neurosteroids. These are brain hormones that regulate mood. Animal and human studies have shown that finasteride reduces levels of allopregnanolone, a specific neurosteroid involved in mood regulation.

When these mood-regulating hormones drop, some people experience profound psychiatric reactions. What makes finasteride particularly concerning is that these effects can persist long after someone stops taking the medication. Changes involving brain cell growth, inflammation in the brain, and shifts in how genes function may explain why some people continue suffering even after discontinuing the drug. These lasting changes can affect memory, emotion processing, and stress response.

Massive Underreporting Hid the Problem for Years

Brezis estimates that approximately 4.6 million people worldwide were taking finasteride before 2010. The European Medicines Agency more recently estimated around 270 million patient-years of exposure. Adherence rates mean the actual number exposed to the drug over 20 years could be two to four times higher, since many people try it briefly before stopping.

Based on normal population rates of depression and suicide, and assuming a 57% increase in depression risk from the studies, Brezis calculates that finasteride exposure may have caused hundreds of thousands of cases of mood alterations and depression worldwide.

For suicide specifically, the numbers become grimmer. At baseline population suicide rates of 14 per 100,000 per year, a population of 4.6 million people should see about 6,440 suicides over 10 years. Yet by 2011 (18 years after finasteride’s approval), only 18 suicides had been reported to the FDA’s adverse event system. By 2024, that number had climbed to 320, still far below the expected 19,320 for 30 years of observation.

This massive underreporting happens for multiple reasons. After someone dies by suicide, they cannot report the adverse event. Family members may not know the person was taking finasteride, or may not connect it to the death. Similarly, when someone experiences suicidal thoughts, neither patient nor doctor may link those thoughts to a hair loss medication.

Warning Signs Emerged in 2002: Why Did It Take 20 Years to Act?

Warning signs appeared in 2002, when researchers reported a case series of 19 patients who developed depression during finasteride treatment for hair loss. These patients recovered after stopping the medication, and when two agreed to try the drug again, their depression returned. In 2006, a prospective study of 128 patients showed a significant increase in depressive symptoms and concluded that finasteride should be prescribed cautiously for patients at high risk of depression.

Despite these early signals, the FDA didn’t add depression to finasteride’s label until 2011. The agency’s 2010 safety review noted that reports of suicide ideation, attempts, and completed suicides were “lower than expected,” but the FDA didn’t request the type of analytical studies that could have revealed the true scope of the problem.

Not one of the eight major postmarketing studies uncovering these risks was performed by Merck (the drug’s manufacturer) or requested by regulators. Merck itself had published research in 2006 demonstrating that disproportionality analysis tools “demonstrate sufficient sensitivity and specificity to be considered for use as an adjunct to conventional signal detection methods.” Yet the company apparently never applied these tools to finasteride.

Since 2013, Merck has invested millions of dollars to access real-world patient databases. The company claims on its website that “the safety of patients treated with our medicines is our top priority.” Organon, another finasteride manufacturer, recently stated: “Nothing is more important to Organon than the safety of our medicines and the people who use them.” Yet neither company published the type of database analyses that independent researchers later performed.

Studies may have been performed but not published. If so, these studies would likely have detected worrisome signals as eight others had. Merck might have dismissed such findings, as it had steadfastly denied that Vioxx increased the risk of myocardial infarction shown in its own studies.

What the FDA Knew and When They Knew It

In 2010, the FDA’s safety review discussed depression as a possible side effect of finasteride. The agency noted that reports of suicide ideation, attempts, and completed suicides were “lower than expected,” but did not request the type of analytical studies that could have revealed the true scope of underreporting.

Evidence that later emerged from a legal trial over a finasteride user’s suicide revealed that FDA expert reviewers had recommended adding “suicidal thoughts and behavior” to the label as early as 2010, but that internal advice was rejected by the agency without public disclosure of the discussion or rationale.

In 2022, the FDA responded that it agreed to include suicidal ideation and behavior as an adverse reaction but not as a warning. It remains unclear what made the agency take five years to generate this response without requesting or performing any new study.

The delay in recognizing finasteride’s neuropsychiatric effects raises questions about drug safety monitoring. Clinical trials are designed to determine whether medications work, not whether they’re safe over the long term. Postmarketing surveillance requires different tools: disproportionality analysis (comparing adverse event reports for one drug against others) and data mining in healthcare records (comparing outcomes between users and non-users).

These tools were quickly applied to evaluate suicidality from weight loss medications. Why the long delay before determining suicidality risks from finasteride? Because of this delay, post-finasteride syndrome was still thought of as a nocebo effect (where patients suffer from delusions related to media coverage) as recently as 2019, even though suicide has not been reported with the nocebo effect.

How Many People Were Affected? Estimating the Toll

Depression carries substantial costs beyond human suffering. According to the review, direct and indirect costs including treatment and lost productivity average about $24,000 per patient per year based on current estimates. A 50% increase in depression rate among finasteride users could translate globally into 200,000 people suffering from depression at a cost of $4.8 billion annually, a figure the review notes would exceed the industry’s profit from the drug.

These are estimates based on population exposure, baseline rates of depression and suicide, and the increased risks documented in the eight studies. The true numbers could be higher or lower, but they indicate a potentially significant public health problem that went unaddressed for two decades.

What This Means for Finasteride Users Today

Stopping a hair loss medication should be a simple calculation when weighed against severe depression and death. But for two decades, the system designed to catch these problems failed. Young men taking finasteride “just” to improve their appearance had no way to know they might be risking their mental health and their lives. Some doctors still remain unaware of the psychiatric risks, making true informed consent nearly impossible.

Finasteride has been shown to work for treating hair loss, although most trials were small, short-term, and conducted by the industry with moderate quality of evidence. A recent analysis appears to challenge its usefulness in the long run. Yet many young people like this medicine to enhance their appearance, often getting it over the internet without a physician’s prescription.

An informed consent form has been suggested to help preserve a patient’s right to get a cosmetic drug while being aware of its potentially severe side effects. Genuine shared decision-making is, however, unlikely to happen, as most physicians themselves are still unaware of the neuropsychiatric reactions to finasteride.

What Needs to Change: Policy Recommendations

Brezis concludes with clear policy recommendations. Marketing of finasteride for hair loss should be suspended until manufacturers provide new safety evidence or develop a molecule that doesn’t cross the blood-brain barrier. Before approving medications, regulators should require manufacturers to commit to ongoing surveillance studies and enforce that requirement. Medical examiners should systematically record medication histories for all suicides to better track these connections.

The two-decade delay in recognizing finasteride’s neuropsychiatric effects allowed preventable harm from a cosmetic medication. Whether that harm could have been avoided had manufacturers and regulators acted on early warning signals remains an open question, but one with serious consequences for how drug safety is monitored.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. If you are taking finasteride and experiencing mental health symptoms, consult your healthcare provider. If you are experiencing suicidal thoughts, contact the National Suicide Prevention Lifeline at 988 or seek immediate medical help.

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