The prescribing information for Propecia (finasteride 1 mg) lists depression, suicidal ideation and behavior among adverse reactions identified during post-approval use. Studies of mood give mixed answers, with some reporting an association and others reporting none. The sources below are label listings, cohort studies, systematic reviews and analyses of spontaneous reports. Cohort studies and spontaneous reports cannot show cause and effect.
Label listings and a crisis line
The label lists depression, suicidal ideation and behavior under Nervous System/Psychiatric among post-approval adverse reactions. Its Patient Information lists depression; suicidal thoughts; and decrease in sex drive that continued after stopping the medication among effects reported in general use.
The label also says these reactions are reported voluntarily from a population of uncertain size, so it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. The Patient Information says to tell your healthcare provider if you have any side effect that bothers you or that does not go away.
The National Institute of Mental Health suicide prevention page says anyone struggling or having thoughts of suicide can call or text the 988 Suicide & Crisis Lifeline at 988, and people should call 911 in life-threatening situations.
Observational cohort studies
Cohort studies compare groups of people without assigning treatment, so they cannot show that a drug caused an outcome. The Ontario study below covers older men, a different group from men taking finasteride 1 mg for hair loss.
An Ontario, Canada study was a population-based, retrospective, matched cohort of 93 197 men ages 66 years or older. It asked whether older men starting a 5-alpha-reductase inhibitor (5-ARI) for prostatic enlargement had a higher risk of suicide, self-harm, or depression. Men who used 5-ARIs were not at a significantly increased risk of suicide (HR, 0.88; 95% CI, 0.53-1.45). Depression risk was elevated during the initial 18 months (HR, 1.94; 95% CI, 1.73-2.16) and continued to be elevated to a lesser degree afterward (HR, 1.22; 95% CI, 1.08-1.37). Self-harm risk was significantly increased during the initial 18 months (HR, 1.88; 95% CI, 1.34-2.64), but not thereafter.
A Swedish register-based cohort study included 2 236 876 men aged 50 to 90. Exposure was a recorded prescription of finasteride or dutasteride and duration of use, and the abstract does not state the dose. The authors concluded that both drugs were similarly associated with depression with a constant risk over time, while neither drug was associated with suicide.
A UK Biobank cohort analysis found that finasteride use was not significantly associated with depression or suicide events, whether or not covariates were considered. The abstract does not state the dose.
Systematic reviews and meta-analyses
A 2021 systematic review of reports on finasteride treatment (the abstract does not separate doses or indications) found crude pooled rates of depressive symptoms of 3.33% with versus 2.54% without finasteride, and a random-effects meta-analysis odds ratio of 2.14 (1.40-3.27).
A 2024 mini systematic review and meta-analysis of five studies involving 2213600 patients found no statistically significant association between 5-ARI exposure and the risk of depression. A 2026 meta-analysis of observational studies of 5-ARIs and the risk of suicide and neuropsychiatric symptoms, covering patients with enlarged prostate (BPH) or androgenetic alopecia, reported overall no statistically significant differences between 5-ARI users and comparison groups (HR 1.07, 95% CI: 0.76-1.51), with substantial heterogeneity across studies (I² = 59%).
Spontaneous-report analyses
These analyses compare how often a drug appears in adverse-event reports. A 2025 international pharmacovigilance analysis found a statistically significant disproportionality in reports of suicidality and depression associated with finasteride use, and its authors state the study does not imply causality.
A 2015 analysis of FDA Adverse Event Reporting System reports on low-dose finasteride noted disproportional reporting in suicidal ideation events, although it did not reach signal threshold (EBGM 1.72; 95% CI 1.31-2.23). Such reports cannot establish how often suicidal ideation occurs.
What this does not tell you
Cohort studies and report analyses cannot show cause and effect. The findings point in different directions. The Ontario cohort found higher depression risk (greater in the first 18 months) and higher self-harm risk in the first 18 months, but no significant increase in suicide. The Swedish cohort found an association with depression but not suicide. The 2021 review found a higher pooled rate of depressive symptoms with finasteride. The UK Biobank analysis and the 2024 and 2026 meta-analyses reported no statistically significant association or difference.
The Ontario study is in older men starting 5-ARIs for prostatic enlargement, and several abstracts do not state the dose, so these results should not be read as results for the 1 mg hair-loss tablet unless the source states that dose. An American Family Physician review abstract also states that patients with moderate to severe hair loss are more likely to have accompanying anxiety, depression, and lower work productivity and quality-of-life scores, which makes mood studies in this group harder to read. None of these sources can tell a man how finasteride would affect his own mood. A licensed provider can discuss mood history and what to watch for.