Popular hair-loss pill linked to depression and suicide

For more than two decades, finasteride has been prescribed to millions of men seeking to slow or reverse hair loss. Behind its cosmetic appeal, however, evidence has continued to emerge suggesting serious mental health consequences, including depression, anxiety, and in some cases, suicide.

Prof. Mayer Brezis of the Hebrew University of Jerusalem argues that both the medical community and regulators have repeatedly failed to protect the public by overlooking signs of psychiatric harm associated with the drug.

His review analyzed data from eight large studies published between 2017 and 2023. The findings show a clear trend: people who used finasteride were far more likely to experience mood disorders and suicidal thoughts than those who did not. This pattern appeared consistently across various national databases, including the FDA's adverse event system and healthcare records from Sweden, Canada, and Israel.

"The evidence is no longer anecdotal," said Prof. Brezis, a professor emeritus of medicine and public health. "We now see consistent patterns across diverse populations. And the consequences may have been tragic."

The report estimates that hundreds of thousands of users may have suffered from finasteride-related depression, and that hundreds -- possibly more -- may have died by suicide. Originally approved by the FDA in 1997 for male pattern baldness, the drug has remained popular for its perceived safety and effectiveness, particularly among younger men. Critics say, however, that its risks were downplayed or ignored.

A Delayed Response, With a High Cost

Although the FDA recognized depression as a possible side effect in 2011 and added suicidal thoughts to the label in 2022, researchers had been warning of potential dangers as early as 2002. Internal FDA files from 2010, cited in Brezis' review, contained entire sections redacted as "confidential," including estimates of how many people might have been affected.

By 2011, only 18 suicides linked to finasteride had been reported to the FDA. Based on worldwide usage, Brezis concluded the actual number should have been in the thousands. "It wasn't just underreporting," Dr. Brezis wrote. "It was a systemic failure of pharmacovigilance."

Unlike drugs used to treat obesity or psychiatric disorders, which are often closely monitored after approval, finasteride's classification as a cosmetic treatment may have shielded it from deeper scrutiny. None of the data-mining studies referenced in the review were initiated by Merck, the company that developed the drug, nor were they commissioned by regulatory authorities.

A Cosmetic Drug With Life-Altering Risks

Brezis argues the drug's classification as a non-essential, appearance-enhancing medication changes the risk calculus. "This wasn't about life or death medical necessity," he said. "This was about hair."

The biological rationale is clear. Finasteride works by blocking the conversion of testosterone into dihydrotestosterone (DHT), but in doing so, it may also disrupt neurosteroids like allopregnanolone -- linked to mood regulation in the brain. Animal studies have shown long-term effects on neuroinflammation and even changes in hippocampal structure.

For some patients, the consequences don't end when the pills do. Reports of lingering symptoms -- dubbed "post-finasteride syndrome" -- include insomnia, panic attacks, cognitive dysfunction, and suicidal thoughts that persist months or even years after stopping treatment.

Regulatory Gaps, Corporate Silence

The report is especially scathing toward the FDA and Merck. Despite having access to millions of patient records and robust pharmacovigilance tools, neither party acted in time, Brezis argues. The industry's silence was strategic, he suggests, driven by market pressures and legal liability -- echoing past controversies like Merck's handling of Vioxx.

"Nothing is more important to Organon than the safety of our medicines," the company recently claimed in a public statement. Yet none of the safety studies cited were initiated by the manufacturer.

The FDA, meanwhile, took five years to respond to a citizen petition calling for a black-box warning. Its final decision? To add suicidal ideation to the label -- but not as a formal warning.

What Now?

Brezis is calling for immediate changes in how drugs like finasteride are approved, monitored, and prescribed. His recommendations include suspending marketing of the drug for cosmetic purposes until safety is re-established, mandatory post-approval studies with strict enforcement, and systematic recording of drug histories in suicide investigations.

"For many, those changes come too late. The paper is dedicated to one such individual -- a previously healthy man who took finasteride "just" to improve his hair. Within days, he spiraled into severe psychiatric distress. He never recovered. Months later, he took his own life."