Weighing the risks of taking finasteride

The points below are based on firsthand reports, adverse event reports to FDA, published research, doctors’ perspectives, the FDA-approved drug label and personal experience. These points concern finasteride as a treatment for hair loss in younger men.

Key points

  1. Finasteride lowers availability of the androgen dihydrotestosterone, or DHT, by inhibiting an enzyme. Read more about how finasteride works here.
  2. Some men who took finasteride and then discontinued the drug have reported severe adverse effects which do not respond to treatment, do not resolve over time, and may be irreversible. See firsthand experiences and adverse event data.
  3. The drug label approved by the U.S. Food & Drug Administration includes reports of sexual adverse effects that “continued after stopping the medication.” A recent systematic review included 11 studies which described men experiencing irreversible sexual adverse effects after stopping finasteride. A clinical trial sponsored by Merck reported that one man’s sexual adverse experiences on finasteride did not resolve with continued treatment (Overstreet et al., 1999).
  4. Beyond loss of sexual function and sexual desire, men have reported psychological, cognitive, sensory and physical symptoms as well as sleep problems that continue after stopping finasteride (“persistent adverse effects“).
  5. There is no way to assess your risk of getting persistent adverse effects.
  6. There is no effective treatment for persistent adverse effects.
  7. Men have reported persistent adverse effects after taking as little as one pill of finasteride.
  8. There is no published evidence that that taking finasteride at a lower dose or lower frequency would reduce the risk of persistent adverse effects.
  9. A paper found that among younger men, longer duration on finasteride was the strongest predictor of developing erectile dysfunction that continues after stopping the drug (Kiguradze et al., 2017).
  10. Regarding semen, sperm and fertility:
    • There have been reports to FDA of malformed embryos and spontaneous abortion following paternal exposure to finasteride (Zakhem et al., 2019). The review, published in the Journal of the American Academy of Dermatology, noted: “spontaneous abortion…may be a risk associated [with] finasteride use.”
    • At a higher dose of 5 mg, after 26 weeks men who took finasteride had reduced sperm count, concentration, motility (movement) and semen volume. 52 weeks into treatment, three of these four parameters improved; sperm motility did not improve. 24 weeks after stopping treatment, sperm motility remained significantly lower than before starting finasteride treatment. (Amory et al., 2007).
    • A 2013 study concluded: “Finasteride should be…used with caution in men who desire fertility.” (Samplaski et al., 2013)
    • In June 2021, FDA added a new adverse event to the Postmarketing Experience section of the Propecia (finasteride 1 mg) label: hematospermia, or blood in semen.
  11. Based on patterns observed in firsthand reports (anecdotal evidence):
    • If you have a diagnosis of, or predisposition to, depression, bipolar disorder, an anxiety disorder or obsessive-compulsive disorder, you may be at higher risk of adverse effects.1
    • If you have previously taken any of the following, you may be at higher risk of persistent adverse effects: SSRI/SNRI antidepressants, finasteride, dutasteride, saw palmetto or Accutane/isotretinoin.
    • If you decide to take finasteride, stopping and restarting the drug could increase your risk of persistent adverse effects.
  12. In 2021, an international group of doctors and researchers published diagnostic criteria for post-finasteride syndrome (Healy et al., 2021).

1 This does not mean persistent adverse effects have a purely psychological origin; rather, that those with psychiatric diagnoses or predispositions may be more susceptible to adverse effects emerging from treatment with finasteride. See research on psychological adverse events here.

More information

References

Belknap SM, Aslam I, Kiguradze T, et al. Adverse Event Reporting in Clinical Trials of Finasteride for Androgenic Alopecia: A Meta-analysis. JAMA Dermatol. 2015. DOIPubMed

Diviccaro S, Melcangi RC, Giatti S. Post-finasteride syndrome: An emerging clinical problem. Neurobiol Stress. 2019. DOIPubMed

Healy D, Bahrick A, Bak M, et al. Diagnostic Criteria for Enduring Sexual Dysfunction after Treatment with Antidepressants, Finasteride and Isotretinoin. Int J Risk Saf Med. 2021 Oct 26. DOIPubMed

Howell S, Song W, Pastuszak A, Khera M. Differential Gene Expression in Post-Finasteride Syndrome Patients. J Sex Med. 2021 Sep. DOIPubMed

Khera M, Than JK, Anaissie J, et al. Penile vascular abnormalities in young men with persistent side effects after finasteride use for the treatment of androgenic alopecia. Transl Androl Urol. 2020. DOIPubMed

Kiguradze T, Temps WH, Yarnold PR, et al. Persistent erectile dysfunction in men exposed to the 5α-reductase inhibitors, finasteride, or dutasteride. PeerJ. 2017. DOIPubMed

Saengmearnuparp T, Lojanapiwat B, Chattipakorn N, Chattipakorn S. The connection of 5-alpha reductase inhibitors to the development of depression. Biomed Pharmacother. 2021 Aug 31. DOIPubMedFull text via ScienceDirect

See more papers on persistent adverse effects of finasteride and ‘post-finasteride syndrome’.