A widely prescribed hair loss medication may have contributed to hundreds of suicides and thousands of cases of depression worldwide, according to a comprehensive new review that exposes decades of regulatory inaction despite mounting evidence of serious psychiatric risks.
The review, published in The Journal of Clinical Psychiatry by Professor Mayer Brezis of Hebrew University of Jerusalem, presents compelling evidence linking finasteride—sold under brand names including Propecia—to significantly increased rates of depression, anxiety, and suicidal behavior across multiple global populations.
Two Decades of Overlooked Evidence
Finasteride, approved by the FDA in 1997 for male pattern baldness, works by blocking the conversion of testosterone into dihydrotestosterone (DHT). However, this mechanism also interferes with the brain's production of neurosteroids, including allopregnanolone, a key regulator of mood and stress response. Animal studies have demonstrated that disrupting these neurosteroids can cause neuroinflammation and structural brain changes, particularly in the hippocampus, an area linked to depression.
The review draws on global data from adverse event reports, clinical studies, and national health registries. Across eight major studies conducted between 2017 and 2023, researchers consistently found that users of finasteride were significantly more likely to develop mood disorders or suicidal thoughts compared to non-users. This pattern appeared in multiple countries, including the US, Sweden, Canada, and Israel, and across different populations.
"The evidence is no longer anecdotal," Brezis stated. "We now see consistent patterns across diverse populations. And the consequences may have been tragic."
Post-Finasteride Syndrome and Persistent Effects
Reports highlight what has been termed post-finasteride syndrome (PFS)—a condition where symptoms such as insomnia, panic attacks, cognitive impairment, and suicidal ideation persist long after discontinuing the medication. For some patients, the effects have lasted months or even years, suggesting potentially irreversible neurological changes.
Finasteride users have reported ongoing symptoms even after the drug is stopped, including insomnia, panic attacks, cognitive dysfunction and suicidal thoughts, according to the research findings.
Regulatory Response and Industry Criticism
Despite early warnings dating back to 2002, both Merck, the drug's manufacturer, and the FDA have faced criticism for their delayed response. The FDA first acknowledged depression as a side effect only in 2011, nearly fifteen years after finasteride's approval, and added suicidality to the drug's label in 2022.
Internal FDA documents from 2010, cited in Brezis's paper, contained entire sections redacted as "confidential," including estimates of how many patients may have been affected. The agency recorded 18 suicides linked to finasteride in 2011, although Brezis argued that the number should have "ranged in the thousands."
According to the review, this long-term neglect represents a systemic failure of pharmaceutical oversight. Brezis estimates that hundreds of thousands of men worldwide may have suffered from depression due to finasteride use, and that hundreds—if not more—may have died by suicide.
Risk-Benefit Assessment for Cosmetic Use
Brezis argues that because finasteride is a non-essential cosmetic drug, the acceptable risk threshold should be far lower than for life-saving medications. "This wasn't about life or death medical necessity," he said. "This was about hair." Yet, despite its elective use, regulators and physicians continued to prescribe the drug widely, even as mounting evidence suggested potentially severe psychiatric side effects.
"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," the author wrote in the study. "Over 20 years worldwide, hundreds of thousands may have endured depression, and hundreds may have died by suicide."
Calls for Regulatory Reform
The review's findings have renewed calls for urgent regulatory reform. Brezis proposes several measures including suspending marketing of finasteride for cosmetic use until its psychiatric safety is fully re-evaluated, mandatory post-approval studies and stricter enforcement of safety monitoring, and systematic recording of medication histories in suicide investigations to identify potential drug-related links.
In a statement to Fox News Digital, Brezis confirmed that physicians frequently prescribe finasteride "offhandedly because they are not aware of its risks." He noted that "young people often get it from the internet without realizing it can cause anxiety, depression and even suicidal thoughts, in addition to sexual impairment."
"My recommendation to patients and physicians: Stay away from this medication," he said. "My recommendation to the FDA: Take it off the market."
Industry and Regulatory Response
Organon, formerly part of Merck and current manufacturer of Propecia and Proscar, provided a statement defending their products: "Organon stands behind the safety and efficacy of its finasteride products. Regulatory agencies around the world thoroughly reviewed the safety and efficacy data for these medicines before their approval, and they, together with Organon, have continued to review additional safety and efficacy data in the decades that these products have been on the market as part of the rigorous, routine post-marketing surveillance process."
The U.S. Department of Health and Human Services responded that "the FDA advises patients to discuss the potential risks and benefits with their healthcare providers before using any pharmaceutical product. This is particularly important as the FDA has not approved any topical finasteride products, which have been associated with numerous adverse effects reported to the agency."
