An objective view on the post-finasteride syndrome based on 12 studies!

written by Matt Dominance

In this post I´m going to share my thoughts on the likelihood of any Finasteride user experiencing  post-finasteride syndrome or any sexual – /psychological – related side effects during or after discontinuing Finasteride treatment.

This post also gives you some useful suggestions on how to minimize the potential side effects of Finasteride while using it for successful hair loss management long – term.

Out of all 14 studies I was able to find on this topic, there are 4 studies which are suggesting the the occurrence of PFS is real and 8 studies suggesting safety of finasteride with no or minimal side effects of any kind. 

Here is a brief summary I especially liked on this topic coming from the International Journal of Trichology

Post-finasteride syndrome is obviously a problem that has to be dealt with. Low quality studies neither confirm nor refute the condition as a valid entity. 

Therefore, it would be only as inappropriate to dismiss the PFS as nonsensical, as it is to demonize finasteride for the treatment of male pattern hair loss.

The authors found that persistent sexual side effects were only documented in low-quality studies with strong bias selection, while a significant nocebo effect has been documented among patients informed about the possible side effects of finasteride. 

Let´s talk about statistics!

The higher the sample size of observed subjects in any study, the higher the statistical significance the study will have.

Statistical significance is the likelihood that a relationship between two or more variables is caused by something other than chance

Two variables in our case are: 1. Taking oral Finasteride, 2. Experiencing sexual side effects/post-Finasteride syndrome

A statistically significant experiment means that you can be almost sure that the results you observed are reliable and not distorted by selection bias for example.

The smaller the sample size, the less reliable the results are being considered from statistical point of view.

post - Finasteride syndrome probability

Statistical significance can be only present by studies which were done on large enough samples sizes. Sample sizes of 10, 20, 50 or even 100 are still considered to be very insignificant when it comes to statistical evaluation.


What is PFS Foundation?

 PFS foundation website focuses on documentation of individual post-finasteride syndrome cases all over the globe. It has been active since 2012 and documents 16,125 cases of post-finasteride syndrome to this day (28.1.2020). 

Furthermore, they also register 63 known suicides – which supposedly happened as a result of using finasteride.

 Their ultimate goal is to have Finasteride removed from the market completely. 

Are men becoming suicidal as a result of PFS? The truth…

Based on PFS foundation website there have been over 16,000 detected cases of post – finasteride syndrome and 63 known suicides between 2012 and 2020 so far.

Which makes it around 2000 adverse reactions per year and 8 suicides per year.

Finasteride has been approved for hair loss in 1997, which makes it the most frequently prescribed drug for treating hair loss with over 70.000.000 prescriptions between 2007 – 2017 (just in the USA) based on

Don´t you think that if you randomly select 70.000.000 Americans and observe them for 10 years, you will realize that 63 of them may easily try to kill or actually kill themselves anyways because statistically, the occurrence of such event by a sample size of 70.000.000 million is very likely regardless of whether the whole sample have been on Finasteride or not.

Actually, according to CDC´s National Center for Health Statistics the male suicides in the USA have been averaging from approx. 25.000 – 35.000 during 1997 – 2016.


Temporary and persistent sexual side effects. How likely are they to occur?

1-6 Studies suggesting the existence of post-finasteride syndrome. How reliable are they?

Study 1 (2015) 
472 men between 47 and 68 years of age on 5 mg oral finasteride per day for 45 months


Testosterone levels in men treating with Finasteride for BPH (benign prostatic hyperplasia) decreased after taking Finasteride. Erectile dysfunction symptoms were also observed as a result of taking Finasteride. 

Limitations: (selection bias)

Sample size consists of middle-aged and older man with naturally lover testosterone production and thus more prone to erectile dysfunction

Study 2 (2011) 
 71 otherwise healthy men aged 21-46 years experienced sexual-related side effects 3 months after discontinuing the finasteride treatment


Persistent sexual dysfunction associated with the use of finasteride:

Low libido: 94%

Erectile dysfunction: 92% Decreased arousal: 92%

Problems with orgasm: 69%


Very low sample size: 72 men

Study 3 (2012) 
54 men experienced persistent sexual side effects as a result of using Finasteride


Persistent sexual side effects continued longer than 6 years after discontinuing the treatment (by 20% of men in the sample) and by the rest 80% side effects resolved after 14 months after stopping Finasteride on average.


Very low sample size: 54 men, no age information, no previous data about the lifestyle and health condition of the selected sample which could have contributed to sexual side effects

Study 4 (2014) 

8 men (aged 29-43 years) reporting sexual side effects including loss of penis sensitivity over 6 months after discontinuation of finasteride who were interviewed and clinically visited.


Side effects persisted for more than 6 months after discontinuing the treatment


Very low sample size: 8 men

Report 1 (online survey from 2015)

131 generally healthy men participated in an email survey 


Side effects like exual libido, ejaculatory disorders, disorders of the penis and testes, cognitive symptoms, and psychological symptoms were present even 6 months after discontinuing the treatment 


Online survey – not a real clinical study with a proper pre-examination of the observed sample

Study 2 (online reports from 1998-2013)

4910 reports on Finasteride-related adverse event reports for men aged 18-45 were submitted between 1998 – 2013. These men were taking the standardized dose of Finasteride – 1mg per day.


11.8% of the reports (577) experiencing persistent sexual side effects even after discontinuing Fiansteride. 



7-14 Studies suggesting safety of finasteride. How reliable are they?

Study 7 (2012)

3177 Japanese men with androgenetic alopecia participated in this study in order to observe the safety and efficacy of finasteride 1 mg tablet daily from 2006 – 2009


23 out of 3177 men experienced adverse reaction (study doesn´t specify whether these side effects were of sexual nature or not)


No follow-up examination of many patients in this study. 

Study 8 (1998)

In two 1-year trials, 1553 men (18 to 41 years of age) with male pattern hair loss received oral finasteride 1 mg/d or placebo, and 1215 men continued in blinded extension studies for a second year. 


No mentioning of any sexual-related side effects in this study.


No information about the safety of finasteride in this study neither about the potential side effects. Study focused on observing the efficacy of finasteride instead of its safety. 

Study 9 (2000)

212 men, age 18-40 years received finasteride 1 mg daily or placebo for 48 weeks. Study measured anagen hair count at baseline, 24 weeks and 28 weeks.


Study focused on observing the improvements in hair count before and after 48 weeks of finasteride treatment. The treatment was efficacious. 


No information about the safety profile of finasteride use by subjects during these 48 weeks.

Study 10 (2002)

1553 men with MPHL randomly received either finasteride 1 mg/day or placebo for 5 years.


Study wasn´t able to identify new safety concerns during the long.term use of finasteride. Tolerance of finasteride: well.


Study 11 (2004)

414 Japanese men with male pattern hair loss received finasteride 1 mg (n = 139), finasteride 0.2 mg (n = 137), or placebo (n = 38) once daily for 48 weeks.


General tolerance of finasteride treatment was well and study doesn´t report about any adverse effects.


Study 12 (2006)

Men with AGA randomly received finasteride (1 mg/d) or placebo for 192 weeks. 


Study wasn´t able to identify new safety concerns during the long.term use of finasteride. Tolerance of finasteride: well.


The sample size available for analysis decreased with time.

Study 13 (2007)

120 patients, sexually active, randomly received finasteride 5 mg concealed as an “X” compound of proven efficacy for the treatment of BPH” for 1 year

Group 1 (n=52) didn´t receive any information about potential sexual side effects related to this drug.

Group 2 (n=55) received information about potential sexual side effects related to this drug ( erectile dysfunction, decreased libido, problems of ejaculation).


Petients, who received the information about the potential side effects prior to the start of the treatment were more likely to experience sexual side effects (43.6%) as opposed to the group 2 (15.3%) – not knowing about the potential side effects.


Small sample size of each group (52 and 55 subjects respectively).

Study 14 (2003)

During 24 month period  424 men aged 41-60 years received finasteride 1 mg on hair growth/loss 


General tolerance of finasteride treatment was well and study doesn´t report about any adverse effects.


Leave a Reply

Your email address will not be published. Required fields are marked *