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Post-finasteride syndrome


Post-finasteride syndrome is now a recognised condition, affecting as many as 20 per cent of those taking finasteride or who have ever taken this drug for whatever reason — benign prostatic hyperplasia, prostate cancer or male pattern baldness. The sexual side-effects of finasteride may be persistent or permanent.1

The persistent sexual side-effects of finasteride may manifest after varying periods of taking the drug, or not until the drug is discontinued. It is not known why some men are susceptible to the potential adverse affects of finasteride, while others — the majority — are not affected.

Persistent adverse effects of finasteride in younger men include erectile dysfunction, low libido, lack of orgasms and depression. One study has found lower levels of several neurosteroids in this population. Out of the various, persistent side-effects, erectile dysfunction and alcohol consumption issues have been the most studied in animal models. Further research is needed on who is susceptible to the persistent, adverse side-effects of finasteride and on the underlying mechanisms of the medication.2

Fourteen young men have presented with post-finasteride syndrome and in addition to the adverse events reported above, common symptoms have included:

  • Nocturnal urinary frequency that does not respond to anti-spasmodic therapy.
  • Penile numbness, most particularly in the area of the fraenulum.
  • ‘Brain fog’ and difficulty in concentrating.
  • Misshapen penis, sometimes described as Peyronie’s disease. In my view, it is more Peyronie’s-like and is probably due to the laying-down of fibrous plaques along the tunica albuginea in a disorganised fashion.
  • Severe depression and despair. Research is ongoing but it would now appear that there is a significant increased risk of suicide within this population.3
  • Mondor’s disease of the penis, although one cannot be sure if this is finasteride-related.
  • Chronic fatigue syndrome and muscular wasting.

Biological mechanism

finasteride is a 5 alpha reductase inhibitor. It prevents the conversion of testosterone into dihydrotestosterone (DHT). Dihydrotestosterone is the active form of testosterone. Testosterone on its own is inactive. Dihydrotestosterone is found in many parts of the body, including the hair follicles, where it plays a causative role in the development of natural male pattern baldness. It is also found in many brain cells, as part of the brain chemistry playing a role in neurotransmission.

It is rare for any medication to permanently interfere with delicate brain function, such as sensitivity to pleasure or desire or thought processes. However, it now appears that finasteride may have this capacity in a subset of men. To a far lesser extent, SSRIs also have this potential, albeit in a less spectacular way.4 Interfering with brain chemistry is something not to be undertaken lightly.

Management and prevention

Unfortunately, on the question of the management or treatment of the syndrome, there is very little to reference. Research is ongoing, thanks mainly to the sterling work of the Post Finasteride Foundation, which was established in 2011.

Until the underlying biological mechanism of the syndrome is understood, it is difficult to see from where a cure will come to help the thousands of men across the world who are suffering from the issues that this disease can cause.

However, there are some ways that doctors might help patients with post-finasteride syndrome:

  • A good listening ear. Acknowledge that the disease exists and that it has many and varied presentations, including symptoms like penis disfigurement, genital shrinkage and nocturnal urinary frequency.
  • As best you can, try to explain our limited understanding of the syndrome. Never suggest that it is ‘psychological’ or that it is ‘all in your head’.
  • Do not refer to a psychiatrist or psychotherapist, as this may be interpreted as your non-acceptance of post-finasteride syndrome as a real entity.
  • Do not refer to an endocrinologist as they, of necessity, will be no wiser than you.
  • Slightly raise testosterone levels and lower oestrogen levels by the judicious use of testosterone gel and tamoxifen. Here, I use an empirical approach, as I have found that hormonal assay has nothing to offer.
  • Treat erectile dysfunction in the usual way, although post-finasteride syndrome erectile dysfunction is often sildenafil- and tadalafil-resistant.


Since the treatment of post-finasteride syndrome is all but non-existent, it therefore behoves us as doctors to concentrate on prevention.

Here, the key has to be awareness. If men were being told about the effects of finasteride, then it could be argued that very few, if any of them, would be prepared to run the risk for the sake of temporarily growing some hair on their heads. If men were told that up to 20 per cent of those who take finasteride develop sexual side-effects and that these side-effects may be life-long after discontinuing the drug, then that information alone could stop this condition in its tracks.

At the beginning of this article, post-finasteride syndrome was described as ‘iatrogenic’, or doctor-made, and there is a strong argument to support this.

It can be argued that if it were not for doctors prescribing finasteride for natural male pattern baldness, then there would be no post-finasteride syndrome in young men.

We might still find it in older men being treated with finasteride, but at least fit, healthy young men would be spared the devastation that this condition can beget.

It is true that many young men, desperate to find a solution for their natural balding, are going online and purchasing it from online pharmacies. Thus, you might say, at least in these cases, doctors are exonerated. But that is not quite true. All legal online pharmacies are doctor-dependent and have registered medical practitioners in the background, approving prescriptions for whatever it is the client thinks they need.

In these cases, of course the chances of the client being properly warned of the dangers of finasteride are much reduced, since there is little, if any, interface between doctor and patient with online pharmacies.

At the end of the day, it is up to all medical professionals — including doctors, pharmaceutical manufacturers, governments and regulatory authorities — to prevent post-finasteride syndrome by the simple expedient of making it unavailable.

We need to do this urgently because a cure for this disease may still be a very long way off.

  1. Irwig MD et al. Journal of Sexual Medicine. Vol. 9 Issue 11. Pg 2927-2932.
  2. Irwig MD. Sex Med Rev 2014: 24-35.
  3. Clinical Study of Post-finasteride Syndrome Launched at University of Milano-Bicocca and University of Milano Research Aims to Determine why PFS Patients Develop Neurological and Psychological Dysfunction. JSM Vol. 2 issue 4. February 18, 2014.
  4. Journal of Clinical Psychiatry, Vol 59 (Suppl 4), 1998, 48-54.


To help keep yourself updated on developments in research of Post-finasteride syndrome, please see

Case study

Damian is a 29-year-old, single software engineer. He is a non-smoker and light weekend drinker. He takes regular exercise, eats sensibly, looks after his health and is in good physical shape. Three years ago he was prescribed finasteride for his male pattern baldness. He took this drug from May 2009 until September 2011.

While taking it, he noticed no ill effects and it seemed to work very well for him in halting the progress of his balding and even starting the growth of new hair. He was on no other medication.

Having been on the medication for two years and four months, Damian decided he would like to give himself a break and stopped the drug abruptly in September 2011. Within a week of his stopping Proscar, he began to notice some significant symptoms. In the main, these were:

  • Difficulty in achieving or sustaining an erection.
  • Loss of interest in sexual matters — loss of libido.
  • Nocturnal urinary frequency causing sleep deprivation.
  • Penile numbness, particularly in an area behind the fraenulum.
  • Total loss of sensation during ejaculation — sexual anhedonia.

At first, Damian did not make any connection between these symptoms and his having previously taken finasteride. He had been advised about possible sexual side-effects experienced by less than 1 per cent of men while taking the drug and that these symptoms disappeared on discontinuing it. Nobody, however, had mentioned to him of the possibility of side-effects appearing only after discontinuing this hair-loss medication. Indeed, such a concept ran contrary to most people’s notion of drugs’ side-effects.

It was only after exhaustive online research and on finding a website dedicated to post-finasteride syndrome that it began to dawn on Damian that this was indeed what he had.

During this research, my name came up as someone who might know something about his condition and that is why he contacted and consulted with me.

Definition of post-finasteride syndrome

Post-finasteride syndrome can be defined as: “An iatrogenic disease of brain chemistry brought about by an esoteric response to the 5 alpha reductase inhibitor finasteride and characterised by one or many persistent or permanent sexual, physical and intellectual dysfunctions.”


  1. Marty on April 16, 2015 at 10:20 pm

    Thank you Dr Rynne for your efforts to communicate the tragic facts of finasteride. This drug should never be prescribed for cosmetic reasons. There are doctors in Ireland prescribing this drug, claiming it is safe even though they have been made aware that it has seriously damaged the health and lives of many men.
    There is no defence for continuing to irresponsibly prescribe finasteride.

  2. Santiago on March 26, 2015 at 2:21 pm

    Thanks for writing this article, the people affected with this horrible syndrome know how devastating condition is, it is very good news to hear that PFS awareness is increasing and doctors are starting to recognize this as very serious a disease.

    I am crying right now, after years of fighting finally the medical community is focusing on this syndrome.

    Awareness and research is needed to prevent any more needless deaths, or decimation of otherwise happy, productive lives.

    Thank you for speaking up.

    Please keep up the good work.

  3. Santiago on March 26, 2015 at 2:20 pm

    Thanks for writing this article, the people affected with this horrible syndrome know how devastating condition is, it is very good news to hear that PFS awareness is increasing and doctors are starting to recognize this as very serious a disease.

    I am crying right now, after years of fighting finally the medical community is focusing on this syndrome.

    Awareness and research is needed to prevent any more needless deaths, or decimation of otherwise happy, productive lives.

    Thank you for speaking up.

    Please keep up the good work.

  4. Luke on February 19, 2015 at 8:38 am

    This is an excellent article. Though I’m not sure how effective testosterone therapy has been for many men with PFS.
    This is worth reading, as dealing with inflammation seems anecdotally to have helped many men.

  5. Luke on February 19, 2015 at 8:37 am

    This is an excellent article. Though I’m not sure how effective testosterone therapy has been for many men with PFS.

    This is worth reading, as dealing with inflammation seems anecdotally to have helped many men:

  6. Luke on February 19, 2015 at 8:36 am

    This is an excellent article. Though I’m not sure how effective testosterone therapy has been for many men with PFS.

    This is worth reading, as dealing with inflammation seems anecdotally to have helped many men:

  7. Brendan on February 12, 2015 at 3:30 am

    Dr. Bruhin,

    Of course men with PFS should be encouraged to seek psychotherapy as a support system, but not as a first option. The issue here is that many doctors do not know how to treat this condition, or are not familiar with it, and often do not believe the men who have experienced this condition. Then, they refer men to a psychologist/psychiatrist without addressing the specific physical issues occurring.

    I, among others I have been in contact with PFS, have been met with skepticism by urologists who have prescribed Finasteride for years. Pscyhotherapy of course should be encouraged for some men, but other men need solutions and courses of treatment. I believe the medical community is failing with this condition, and am hoping it will improve.

    I wanted to point out a section of this article where Dr. Rynne believes PFS to be a “doctor-made” condition, and I agree with what is said. But PFS is truly a pharmaceutical company-made condition. The fact that Propecia was marketed as a hair loss medication, even though Finasteride has been used for years to treat men aging men with benign prostatic hyperplasia, speaks to the grave irresponsibility of a pharmaceutical giant like Merck, and even more-so, the FDA for approving it. To block 5 alpha reductase enzyme and DHT by 60% in a “hair loss medication” is an absurd notion.

    The multiple label changes Propecia has endured in recent years, to include more side effects, and the fact that this condition may persist even after stopping the medication show the irresponsibility of Merck and the FDA. Drugs need longer testing periods before being approved but are rushed onto the market because financial incentive is more powerful than citizens health.

  8. Dr. Matthew Bruhin on February 11, 2015 at 9:59 pm

    This is a fantastic article, however I would strongly disagree with the doctor’s recommendation NOT to refer to a psychotherapist. There are several very good clinician’s (including myself), who have helped many men with PFS. Many men become suicidal, severely anxious, develop relational problems, or even OCD like symptoms. Having support and clinical help isn’t dismissive, it could save a life! I encourage many men to look into finding therapy as a supportive function as they battle this disorder. There is hope out there and it requires diligence and patience to recover! Hang in there guys we will beat this!

  9. Brendan on February 11, 2015 at 6:05 am

    Dr Rynne, thank you for this informative/helpful piece on PFS. The more awareness we can raise about the condition, the better for the medical community and for those suffering from PFS.

    This condition has drastically altered my life, not only sexually and physically, but mentally as well. Inhibiting 5 alpha reductase for a Cosmetic Purpose is outrageously irresponsible of the medical profession, pharmaceutical industry, etc. It is telling that you cite the figure of 20% of men experiencing PFS, when the labels on finasteride changed multiple times to include more side effects. The label indicates still only 2% of men are effected.

    The most irresponsible fact is that this medication did not specify that this condition could be ongoing, even after stopping the medication, until 2012. I went on finasteride in 2007. If I had known this condition was possibly permanent I never would have taken this pill.

    i believe that finasteride has the ability to change a man’s genetic expression permanently through inhibiting 5 alpha reductase. Side effects appeared the second day on the medication for me, improved while on the medication at points, but worsened and became life altering after stopping the medication.

    I have heard about men micro-dosing themselves with finasteride to combat PFS, taking a very small amount once every several days. Does anyone know anything about this?

    For anyone with PFS, the best advice I can give is to eat very healthy, organic, no preservatives, and raw foods mainly. Also, I take herbal supplements day and at night. The best ally against PFS I have found is through consistent exercise, cardio and strength training. This does not change the sexual side effects at all, but helps with the “brain fog.”

    Thank you again Dr. Rynne. Please keep doing what you can to inform the medical community of this condition.

  10. Mark on January 29, 2015 at 9:11 am

    The drug is insidious. I began taking it in my mid 20s, and noticed no effects for the first couple years (I even joked that men who blamed their ED on Propecia were just looking for a scapegoat). But very gradually, almost imperceptibly, I began to lose my libido and develop ED. By the time I was 30, I realized it had gotten pretty severe and stopped taking the drug. It has been almost 3 years, and there has been almost no improvement. I’m healthy, active, and fit, but that part of my life is destroyed. For a young man hoping to maintain a healthy sexual relationship and build a family, sometimes it feels like so much has been destroyed. I regret the day I started taking the drug, and I resent a company that markets a powerful, poorly understood, hormone-altering drug to young men for many years before admitting to the devastating, life-altering side effects.

  11. James Branson on January 28, 2015 at 7:36 pm

    Thanks for Dr. Rynne for his continued work on raising awareness of PFS, The medical community seems to be filled with lame-brain pseudo-intellectual PFS-denying, “I have science you have anecdotes” nonsense.

  12. Philip Jennings on January 28, 2015 at 12:18 am

    I cannot thank Dr. Rynne enough for speaking out against the dangers of finasteride. Now if we can just get Merck to admit to its “mistake,” all will be well. Until then, be sure to keep up on post-finasteride syndrome clinical research at

  13. Matt on January 27, 2015 at 10:20 pm

    Thank you for speaking up about the horrific dangers of this drug.
    I was a healthy person and very sexually active before using Propecia: since discontinuation I have been suffering from severe hypogonadism and erectile dysfunction. This drug has ruined my life and the life of too many people

  14. John on January 27, 2015 at 8:25 pm

    I took Finasteride for hair loss it destroyed my life. It beyond belief that this drug is given out so easily. If I had taking illgeal drugs I would not have done as much damage to my health.

  15. Ben King on January 26, 2015 at 11:16 am

    Excellent article that is certain to have a positive effect in “PFS World”. Many thanks.

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