• Study of depression from prostate drugs loses the signal by including past users

    Response to: Hagberg KW, Divan HA, Nickel JC, Jick SS. Risk of incident antidepressant-treated depression associated with use of 5α-reductase inhibitors compared with use of α-blockers in men with benign prostatic hyperplasia: a population-based study using the Clinical Practice Research Datalink. Pharmacotherapy. 2017. doi:10.1002/phar.1925 SUMMARY: Hagberg et al, 2017 fails to assess the risk of…

  • Study of ED risk loses the signal by including past users of finasteride

    There is a major limitation: the analysis included past and recent users of 5ARIs, as well as current users. Past users are defined as those who stopped taking a 5ARI at least 91 days before getting diagnosed or treated for ED. Recent users are those who last took the drug 31-90 days before diagnosis or…

  • Mind the gaps: remarks on the evidence base

    This post makes a few not-so-obvious points about the sprawling literature on finasteride and 5-alpha syndrome. If you are new to this literature, consider starting with a brief history of the research and a guide for researchers. Those pages describe what is in the literature, but it is also important to discern what is not…

  • 2023 – year in review

    Fitness influencers and physicians raised alarms about risks of finasteride for hair loss this year, reaching millions of people through tweets, videos and podcasts. On the regulatory front, in France boxed warnings were added to finasteride packaging. Health Canada added a warning about suicidality while the UK regulator launched a safety review. Forty-four relevant research…

  • Most popular pages in 2023

    This year traffic jumped more than 70% over 2022. Here’s a rundown of the 10 most popular pages in 2023.

  • Finasteride appears on Prescrire’s latest ‘Drugs to Avoid’ list

    Prescrire, an independent patient safety organization based in France, has updated its Drugs to Avoid guide. Finasteride appears in the 2024 edition, and has also been included in past editions. The guide notes: Finasteride 1 mg, a 5-alpha reductase inhibitor, has very modest efficacy in androgenic alopecia in men: it increases hair density on the…

  • Stanford urologist discusses risks of finasteride on Huberman Lab podcast

    On November 6, Dr. Andrew Huberman spoke to guest Dr. Michael Eisenberg, a urologist and professor at Stanford Health Care in California. In one segment, they discussed post-finasteride syndrome.

  • Rebuttals to denialists

    Physicians have used flimsy arguments to cast doubt on 5-alpha syndrome. They overlook social context, misread literature, omit inconvenient facts and disparage patients. Rebuttals for each of these arguments are provided.

  • Temperature check on recent literature

    5-alpha syndrome (post-finasteride syndrome) is appearing more regularly in the medical literature. Recent articles show slightly more openness to the syndrome as legitimate, especially in the fields of andrology and sexual medicine. But they continue to recycle old arguments that pin the problem on the patient, such as pre-existing psychological and sexual disorders, a nocebo…

  • Response to Campbell et al on finasteride-associated suicide and depression in men treated for hypogonadism and impotence

    The clear and concerning results in this abstract are statistically significant RORs for suicidal and self-injurious behaviors, anxiety disorders and depressed mood disorders in the finasteride-only group. The suggestion that combination therapy could “decrease” risk or have a “protective” role is unwarranted because the risk ratios are derived from unrelated sets of cases. This study…

  • Urology professor Dr. Ted Schaeffer on Attia Drive: Post-finasteride syndrome is real, drug-related and can be permanent

    Dr. Schaeffer, Chair of Urology at Feinberg School of Medicine, does not recommend finasteride for any man. The prostate cancer expert says he knows people who have post-finasteride syndrome “permanently.” Dr. Edward Schaeffer recently spoke about post-finasteride syndrome on The Peter Attia Drive Podcast, in an episode on prostate health. Dr. Schaeffer is Chair of…

  • Response to Dr. Ralph Trüeb’s writings on post-finasteride syndrome

    A drug-induced syndrome is all in the mind, a Swiss doctor wrote. Editors of the journals had past ties to the drug maker. Men turn to finasteride to try to save their hair, but they might end up with a severe and lasting disability.1 There are countless stories online, usually anonymous because of the embarrassing…

  • Appendix: response to Trüeb

    This appendix accompanies the article: Response to Dr. Ralph Trüeb’s writings on post-finasteride syndrome. Table of competing interests ← back to main article Engagements with Merck re: Propecia Skin Appendage Disorders (journal) (1) International Journal of Trichology (2) Experimental Dermatology (journal) Hair Growth and Disorders textbook (2008) Cited by Trüeb Ralph Trüeb, MD Member, Editorial…

  • Seeking a medical sign of genital numbness

    Some post-5ARI patients experience genital numbness. This symptom can be assessed, but the tests are not easily accessible. This post gives an overview of medical tests which could yield signs of genital numbness and other abnormalities.

  • 2023 – mid-year update

    Drug regulators in France and Canada announced new warnings. A popular podcast discussed post-finasteride syndrome, while men’s fitness influencers urged followers to avoid finasteride.

  • The lost men: how Merck, GSK papered over bad outcomes in trials

    A re-examination of clinical trials of finasteride and dutasteride reveals warning signs of long-term harms to surface later.

  • The lost men – appendix

    A summary of men who had unresolved and severe adverse events in clinical trials of finasteride and dutasteride.

  • From LSD to Zoloft, drugs can leave lasting damage

    SUMMARY: Post-drug disorders are not side effects that linger, but lasting changes that may be severe and irreversible. These disorders are linked to prescribed drugs as well as recreational drugs, and can arise after one dose, long-term use, or abuse. This post covers post-drug disorders linked to use of alcohol, hallucinogens, antidepressants, benzodiazepenes, isotretinoin (also…

  • Men’s fitness influencers are raising alarms about finasteride risks

    Fitness influencers draw in an audience of younger men who want to be stronger, better-performing, and in some cases more attractive. Some guys worry that hair loss will dim their prospects for dating, sex and relationships—or even professional success. In the era of Instagram, body-hacking and telehealth companies such as Hims and Keeps, young men’s…

  • Firsthand experiences – Volume XIII: User reviews

    The websites Drugs.com and Ask a Patient collect reviews of drugs. Here are selected reviews of finasteride, taken by men for hair loss conditions. The dates range from 2008 to 2023.

  • Firsthand experiences – Volume XII: Dutasteride

    Along with finasteride and saw palmetto, dutasteride has been linked a post-drug disorder in some men. This post contains firsthand reports of lasting dysfunctions after taking dutasteride, and stopping the drug.

  • Firsthand experiences – Volume XI: Videos

    Click the video title to view on YouTube where you’ll find a description and comments.

  • Firsthand experiences – Volume X: Saw palmetto & nettle

    Men turn to saw palmetto, a plant-based supplement, because prescription drugs may be unavailable or too costly. Some see the palm supplement as having a lower risk of side effects. Regulators say it is safe, but online, it is not difficult to find reports of men with adverse experiences after using saw palmetto which resemble…

  • Andrew Huberman, PhD discusses post-finasteride syndrome on the Huberman Lab podcast

    Note: In November 2023, Dr. Huberman discussed the risks of finasteride with Dr. Michael Eisenberg. Read the transcript Today’s episode of the popular Huberman Lab Podcast is titled “The Science of Healthy Hair, Hair Loss and How to Regrow Hair.” It includes a five-minute discussion of post-finasteride syndrome. Huberman raises an issue that has been…

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Places to start

  • Thinking about taking finasteride for hair loss? See Weighing the risks.
  • This post compiles research on changes in penile tissue and function associated with finasteride and dutasteride treatment.
  • For a historical perspective, see the timeline which starts with a study in Dominican Republic in the early 1970s.
  • The research bibliography gathers hundreds of papers on adverse effects of finasteride and other 5-alpha reductase inhibitors. See also Research by system & function.


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Harvesters by Pieter Breughel the Elder, 1565 (via Met Museum Open Access)