Finasteride and Depression: Evidence, Risk, and Warning Signs

The relationship between finasteride and depression is one of the more important and controversial areas of finasteride safety research. Regulators in Europe and the UK have added warnings about depression and suicidal thoughts: the MHRA in 2017, 2024 and 2026, and the European Medicines Agency after a review completed in May 2025. The current US Propecia and Proscar labels list depression and suicidal ideation among side effects reported after approval. This page reviews the evidence.

UK and EU Regulatory Warnings

The Neurosteroid Mechanism

The most biologically plausible mechanism linking finasteride to mood changes involves neurosteroids:

1. 5-alpha-reductase converts progesterone into allopregnanolone and other neuroactive steroids
2. Allopregnanolone is a potent positive allosteric modulator of GABA-A receptors, the primary inhibitory neurotransmitter system in the brain
3. GABA-A modulation via allopregnanolone plays a role in anxiety regulation, stress response, mood, and sleep
4. By inhibiting 5-alpha-reductase, finasteride could reduce allopregnanolone levels and theoretically impair GABAergic regulation of mood

This mechanism is supported by Melcangi et al. studies showing reduced allopregnanolone levels in PFS patients, and by the known role of allopregnanolone in mood regulation (allopregnanolone is, in fact, the active metabolite of brexanolone, an FDA-approved treatment for postpartum depression). The mechanism is biologically plausible; it has not been demonstrated to cause depression in clinical populations by prospective study.

What the Epidemiological Evidence Shows

Epidemiological studies on finasteride and depression have yielded mixed results:

• Rahimi-Ardabili et al. (2006) found significant depressive symptoms in men on finasteride 5 mg vs. an untreated group. But the study lacked a placebo control
• A 2021 pharmacovigilance study (Nguyen et al., JAMA Dermatology) found disproportionate reporting of suicidality among men under 45 using finasteride for hair loss; the authors note stimulated reporting may contribute
• Other large database studies have found no significant association between finasteride and depression after controlling for hair loss-related distress itself (which is independently associated with reduced quality of life)

The challenge in this research area: men with AGA already have higher baseline rates of depression and anxiety related to hair loss distress, making it difficult to isolate a drug-specific effect in observational studies.

Who Is Most at Risk?

Men with a personal or family history of depression, anxiety disorders, or mood disturbances are at higher baseline risk for depression regardless of finasteride. These men should have an explicit discussion with their physician about finasteride’s potential neuropsychological risks before starting. The decision to use finasteride in this population should be an informed, individualized one.

Warning Signs: When to Seek Help

• New onset or worsening depression, sadness, or hopelessness after starting finasteride
• Emotional blunting or anhedonia (inability to feel pleasure)
• Suicidal thoughts, seek emergency care immediately (988 Suicide & Crisis Lifeline: call or text 988)
• Significant anxiety, panic, or mood changes temporally associated with starting finasteride

Do not stop finasteride abruptly without consulting your physician if you are experiencing significant mood changes. A physician can help evaluate the cause and manage discontinuation appropriately.

Key Evidence Landmarks

Publication/Event	Year	Design	Key Finding
Melcangi RC et al. neurosteroid studies	2013-2017	Controlled laboratory/clinical cohort	Reduced allopregnanolone (a GABA-A positive modulator with anxiolytic/antidepressant properties) in serum and CSF of finasteride-exposed individuals; provides plausible neurobiological mechanism for mood effects
MHRA Drug Safety Update	2017	Regulatory advice	UK advice to stop finasteride 1 mg if depression develops
Dyson TE et al. (J Urol)	2020	Sequence symmetry analysis, US Veterans Health Administration administrative data	Starting a 5-alpha-reductase inhibitor was not associated with an increased risk of depression; contrasts with registry data
Nguyen DD et al. (JAMA Dermatol)	2021	Pharmacovigilance case-noncase study (WHO VigiBase)	Disproportionate reporting of suicidality and psychological adverse events in patients under 45 using finasteride for alopecia; authors note stimulated reporting may contribute
EMA Article 31 review	2025	Regulatory review	Confirmed suicidal ideation as a side effect of finasteride tablets; frequency unknown; patient card added to 1 mg packs

Evidence Quality Assessment

• Depression as an adverse effect: Regulatory acknowledgment (FDA, EMA labeling) that it can occur; biologically plausible via neurosteroid mechanism; moderate-strength signal from case series and registry data
• Frequency: Not established in general-population studies; selection bias is a major limitation in most high-signal studies
• Suicidal ideation: Present in case series and registry data; EMA label includes it; no prospective population RCT confirms incidence vs. placebo
• Mechanism: Neurosteroid hypothesis (reduced allopregnanolone) is plausible and supported by in-vitro and cohort data, but not confirmed by intervention trial

See also: Post-Finasteride Syndrome | Full side effects hub

Sources

• European Medicines Agency. “Measures to minimise risk of suicidal thoughts with finasteride and dutasteride medicines.” 8 May 2025.
• MHRA. “Finasteride: rare reports of depression and suicidal thoughts.” Drug Safety Update, 24 May 2017.
• Nguyen DD, et al. “Investigation of Suicidality and Psychological Adverse Events in Patients Treated With Finasteride.” JAMA Dermatol. 2021;157(1):35-42.
• Melcangi RC, et al. “Neuroactive steroid levels and psychiatric and andrological features.” J Steroid Biochem Mol Biol. 2017;171:229-235.
• Melcangi RC, et al. “Neuroactive steroid levels are modified in cerebrospinal fluid and plasma of post-finasteride patients showing persistent sexual side effects and anxious/depressive symptomatology.” J Sex Med. 2013;10(10):2598-2603.