Does finasteride affect behavior? Exploring the link to mood, anxiety, and cognition

October 7, 2025 •

3 min read

In 2022, the U.S. Food and Drug Administration (FDA) mandated that the product label for finasteride be updated to include warnings for suicidal ideation and behavior. This regulatory action highlights growing concerns and accumulating evidence that suggest a link between finasteride use and psychiatric and behavioral adverse events.

Quick Summary

Studies and adverse event reports indicate finasteride is associated with mood and cognitive changes, including depression and anxiety. This is likely related to its effect on brain neurosteroid levels, though the association is complex and more pronounced in some individuals, particularly younger men. In some cases, side effects persist after stopping the medication.

Key Points

Depression and Anxiety: Clinical studies and post-marketing surveillance have linked finasteride use to reports of depressed mood and anxiety symptoms.
Suicidal Ideation Risk: Due to accumulated patient reports, the FDA has required the addition of suicidal ideation and behavior to the finasteride product label.
Altered Neurosteroid Levels: The drug inhibits the 5-alpha reductase enzyme, which affects the synthesis of neurosteroids like allopregnanolone in the brain. This can disrupt neural pathways related to mood and cognition.
Cognitive Impairment: Patients and some studies report "brain fog," memory loss, and reduced concentration associated with finasteride use, possibly due to neuroendocrine changes.
Persistent Symptoms (PFS): A subset of men report behavioral and psychological issues that continue after stopping finasteride, a condition called Post-Finasteride Syndrome.
Heightened Risk in Younger Users: Some data suggest psychiatric adverse events may be more pronounced in younger men taking finasteride for hair loss, potentially due to pharmacological effects and psychological factors.
Patient Awareness is Key: Healthcare providers should screen for psychiatric history before prescribing, and patients should be vigilant for any mood or behavioral changes.

The complex link between finasteride and mental health

Finasteride is a 5-alpha reductase inhibitor used to treat male pattern hair loss and benign prostatic hyperplasia. While its primary effects are on hair and prostate health, research and patient reports suggest a potential link between finasteride use and behavioral and psychiatric side effects. Early clinical trials did not consistently identify these mood-related effects. However, post-marketing data has raised concerns, leading regulatory agencies to issue stronger warnings about depression, anxiety, and suicidal ideation. A meta-analysis in 2021 indicated a higher risk of depressive symptoms in finasteride users.

The neurosteroid connection and mechanism of action

The behavioral effects of finasteride are thought to involve its impact on neurosteroids. The enzyme finasteride inhibits is present in the brain, where it helps produce neurosteroids like allopregnanolone. Allopregnanolone influences GABA-A receptors, which are involved in regulating mood and anxiety. By reducing allopregnanolone production, finasteride may disrupt this system, contributing to mood changes, anxiety, and depression.

Cognitive impairment and "brain fog"

Some finasteride users report cognitive issues such as "brain fog," memory problems, and difficulty concentrating. A study involving NHANES and FAERS data found an association between finasteride and cognitive dysfunction. Animal studies have also shown finasteride can affect memory and social behavior.

Post-finasteride syndrome (PFS) and persistent behavioral symptoms

A condition known as Post-Finasteride Syndrome (PFS) describes persistent behavioral and psychological side effects after stopping the medication. Symptoms can include severe memory impairment, insomnia, depression, anxiety, emotional flatness, and suicidal ideation. Reports suggest these symptoms can last for months or longer. The exact causes of PFS are still being studied and may involve lasting neuroendocrine changes.

Nocebo effect versus true biological effects

The role of the nocebo effect in reported side effects is debated. However, animal studies showing finasteride-induced anxiety and depression behaviors, along with changes in neurosteroids, suggest a direct biological effect. Pharmacovigilance data also indicates a disproportionate reporting of psychiatric issues with finasteride. It is likely a combination of pharmacological effects, psychological factors, and individual susceptibility.

Potential behavioral effects of finasteride: A comparison


Behavioral Effect	Description	Potential Link to Finasteride	Evidence Type
Depression	Characterized by low mood, loss of interest or pleasure, and feelings of worthlessness.	Increased risk found in several clinical and observational studies, particularly in younger men.	Clinical studies, meta-analyses, adverse event reports
Anxiety	Symptoms of excessive worry, restlessness, and nervousness.	Reported in some clinical trials and observed in animal models.	Clinical studies, animal studies, patient reports
Suicidal Ideation	Thoughts about suicide.	Added as a warning to finasteride product labels by regulatory agencies in the U.S. and Europe based on patient reports.	Adverse event reports, regulatory mandates
Cognitive Impairment	Difficulties with memory, concentration, and clarity of thought ("brain fog").	Reported by patients and supported by findings from pharmacovigilance databases and some observational studies.	Pharmacovigilance data, observational studies
Emotional Blunting	Reduced emotional response, or anhedonia.	Experienced by some patients, especially those with Post-Finasteride Syndrome.	Patient reports, PFS literature

Conclusion: Navigating the risks of finasteride

The question of does finasteride affect behavior is supported by evidence from both human and animal studies. Although serious psychological side effects are not common, reports of depression, anxiety, cognitive issues, and suicidal ideation have led to regulatory warnings. The proposed mechanism involving neurosteroid disruption provides a plausible biological explanation. In some cases, symptoms may persist after stopping the medication, known as Post-Finasteride Syndrome. Patients should discuss their psychiatric history with their doctor before starting finasteride. A careful assessment of risks and benefits is crucial, especially for younger patients, and awareness of potential mood and cognitive changes is important. Seek medical advice if behavioral changes occur. Further information is available from the Post-Finasteride Syndrome Foundation and health regulatory bodies.

Frequently Asked Questions

Yes, finasteride can cause depressive symptoms. Some studies have indicated an increased risk of depression in individuals taking the medication, and regulatory bodies have added warnings about depressed mood and depression to the product label.

Finasteride is believed to affect mood by altering the levels of neurosteroids in the brain. It inhibits the enzyme 5-alpha reductase, which is involved in producing neurosteroids like allopregnanolone, a modulator of GABA-A receptors linked to anxiety and depression.

Based on post-marketing adverse event reports, regulatory agencies like the FDA and EMA have added warnings about the risk of suicidal ideation and behavior associated with finasteride.

'Brain fog' refers to cognitive difficulties like memory loss, reduced concentration, and slowed thinking. This is a reported side effect of finasteride and has been supported by analyses of adverse event databases.

While many side effects resolve after stopping the medication, some individuals, particularly those with Post-Finasteride Syndrome (PFS), report persistent behavioral, psychiatric, and cognitive symptoms even after discontinuing treatment. The exact cause and permanence are subject to ongoing debate.

According to the NHS, if you are taking finasteride for hair loss and experience low mood or depression, you should stop taking the medicine immediately and contact your doctor for advice. For other symptoms or those on a 5mg dose, consult your doctor urgently.

No. Evidence suggests that younger men using the medication may be more vulnerable to psychiatric effects. Additionally, some studies indicate a potentially higher risk of severe suicidal behavior in patients with a history of mood disorders.

The nocebo effect is when negative expectations of a medication can cause adverse effects. However, documented changes in brain chemistry (neurosteroids) and disproportionate reporting in pharmacovigilance databases suggest a genuine biological effect of finasteride beyond a nocebo response.