If you are considering taking finasteride, see: Weighing the risks of taking finasteride for hair loss
A growing body of evidence has shown that in some men, taking and discontinuing finasteride has led to sexual, neuropsychiatric and other dysfunctions which may last for years after discontinuation and may be irreversible.1-5 A 2019 systematic review reported that 11 of 14 studies on reversibility described patients experiencing “irreversible adverse effects” after discontinuing finasteride.6 Studies have linked the use of finasteride and dutasteride to penile abnormalities. In 2021, an international group of doctors and researchers published diagnostic criteria for post-finasteride syndrome.7
Sexual dysfunction associated with previous use of finasteride or dutasteride may include numb penis, loss of libido, low volume of semen and altered consistency of semen.
Some men appear initially to tolerate finasteride or dutasteride, with adverse effects arising weeks, months or years after starting the drug. After discontinuation, dysfunctions may remain, worsen or resolve. There have been reports of persistent symptoms being triggered by as little as 0.25 mg of finasteride (one-quarter of the standard dose) (see Firsthand reports).
Based on patterns in firsthand experiences, the course may be understood in terms of three phases: post-withdrawal, adaptation and stabilization:
|Phase (time frames approximate)||Description|
|0–3 months after discontinuation||Post-withdrawal. May be an unstable period as the body attempts to recover, with symptoms arising and changing erratically.|
|3–12 months after discontinuation||Adaptation. During this phase, dysfunctions may remain, reduce in severity or resolve.|
|One year after discontinuation and beyond||Stabilization. Dysfunctions remaining after 12 months following discontinuation may be long-lasting and resistant to treatment.|
This figure shows three outcomes: recovery, partial recovery and no recovery:
Although this condition appears to be a post-drug disorder rather than persistent side effects, adverse events reported to FDA provide insight into dysfunctions associated with finasteride. Following are the 28 most common AEs of finasteride in men age 18–40, received by FDA 2018–2020, sorted into categories. These AEs have not been confirmed to be persistent, but likely reflect more serious cases because they were reported to FDA by healthcare providers or consumers.
|Category||AE terms||% of all AEs|
|Sexual anatomy & function||Erectile Dysfunction; Sexual Dysfunction; Organic Sexual Dysfunction; Loss Of Libido; Libido Decreased; Testicular Pain; Genital Hypoaesthesia [penile numbness]; Penile Size Reduced; Penis Disorder; Ejaculation Disorder||21.3%|
|Neuropsychiatric||Depression; Depressed Mood; Anxiety; Suicidal Ideation; Feeling Abnormal; Panic Attack; Anhedonia||15.7%|
|Energy & musculoskeletal||Fatigue; Asthenia; Muscle Atrophy; Arthralgia||5.4%|
|Memory, cognition & attention||Amnesia; Cognitive Disorder; Disturbance In Attention||3.6%|
|Sensory & vestibular||Tinnitus; Dizziness; Vision Blurred||2.9%|
Criteria: Received by FDA: 2018–2020; Sex: Male; Age: 18–40; Suspected product: Finasteride only; Reason for use: Alopecia, Androgenetic Alopecia and other hair loss conditions only (excluding Hair Transplant); Concomitant Products: None.
There is no known effective treatment for lasting dysfunctions after discontinuing finasteride.
Pathophysiology of PFS has not been determined, but recent research has focused on the following hypotheses:
- Altered levels of neuroactive steroids and brain receptor function (e.g., GABA and NDMA)9-12
- Alterations in gene expression2
See also a proposed explanation focusing on tissue injuries, which has not undergone peer review.
3. Kiguradze T, Temps WH, Yarnold PR, Cashy J, Brannigan RE, Nardone B, Micali G, West DP, Belknap SM. Persistent erectile dysfunction in men exposed to the 5α-reductase inhibitors, finasteride, or dutasteride. PeerJ. 2017. doi:10.7717/peerj.3020 • PubMed
5. More papers in Bibliography: Persistent adverse effects & ‘post-finasteride syndrome’
6. Zakhem GA, Goldberg JE, Motosko CC, Cohen BE, Ho RS. Sexual dysfunction in men taking systemic dermatologic medication: A systematic review. J Am Acad Dermatol. 2019. doi:10.1016/j.jaad.2019.03.043 • PubMed
7. 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. doi:10.3233/JRS-210023
8. Merck & Co., Inc. Prescribing information for Propecia.
11. Giatti S, Foglio B, Romano S, et al. Effects of Subchronic Finasteride Treatment and Withdrawal on Neuroactive Steroid Levels and Their Receptors in the Male Rat Brain. Neuroendocrinology. 2016. doi:10.1159/000442982 • PubMed
12. 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. doi:10.1016/j.biopha.2021.112100 • PubMed • Full text via ScienceDirect
13. Montaigne M. A proposed etiopathology of persistent dysfunctions emerging from use and discontinuation of 5-alpha reductase inhibitors: Sequelae of drug-mediated microvasculopathy. doi:10.31219/osf.io/86cnm