Post-Finasteride Syndrome: Real or Imagined?

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Sources of Funding: None


Post-finasteride syndrome (PFS) has recently been recognized as a medical disorder comprising a cluster of sexual, physical, and psychological/neurologic symptoms associated with 5-alpha reductase inhibitor (5ARI) use with purported persistent symptoms despite cessation of drug usage. The aim of this study was to help quantify reports, create a demographic of patient reports, and assess the cluster of symptoms to correlate consistency of the PFS complaints.


We collected the entire dataset of 3,295 Food and Drug Administration Adverse Event Reporting System (FAERS) cases that were submitted from April 2011 to October 2014 on all 5ARIs. We then evaluated the single-dose 5ARI monotherapies and analyzed these cases for symptoms and side effects associated with different doses.


2,048 monotherapy cases using 5ARIs were identified with 1581 being finasteride 1mg, 240 5mg, and 226 of unreported doses. Overall there was an increase event reporting as time progressed with the majority of these involving the 1mg dose. Finasteride was associated with many sexual side effects: decreased libido, ejaculatory disorder, erectile dysfunction, testicular atrophy, orgasmic disorders, hypogonadism, and overall increased sexual complaints. Other common complaints were dermatologic in nature (dry skin or thinning of skin) as well as changes in metabolism (weight gain, elevated glucose, and elevated lipids). Psychological/neurologic conditions of self-harm (suicide), slow cognition, psychological pathologies, emotional anhedonia, insomnia and overall psychological symptoms were prevalent with finasteride use. One mg of finasteride demonstrated more adverse events than the 5mg in the following areas: sexual dysfunction, libido decrease, ejaculation disorders, erectile dysfunction, testicular atrophy, hypogonadism, skin abnormalities, metabolic abnormalities, self-harm, slow cognition, depression, anxiety, emotional anhedonia, and insomnia. Dutasteride was never reported to cause a PFS-like symptom.


FAERS data suggests that finasteride is associated with a diverse collection of symptoms, particularly in the 1 mg dosage. Dutasteride was not implicated for PFS, resulting in only one AE report. Whether or not PFS is real or imagined is not discernable within this context and database.

Michael Butcher
Wesley Baas
Aye Lwin
Bradley Holland
Michelle Herberts
Joseph Clemons
Kristin Delfino
Stanley E Althof
Tobias S Kohler
Kevin T McVary
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