How Merck buried finasteride’s full impact on hormone signaling
Merck held that finasteride had a simple and selective mechanism. In fact, it disrupts hormonal pathways much more broadly. These pathways support the brain, reproductive system and other organs. Merck’s selective account concealed risks which would surface in the decades after approval of Propecia.
Research review: Alterations to penile and prostatic tissue associated with finasteride and dutasteride treatment
Numerous studies have shown that treatment with finasteride and dutasteride can change the size, tissue composition and function of the penis and prostate. Changes to the penis include: reduced size and weight; reduced erectile response; decreased smooth muscle; increased collagen density; and fibrosis (scarring).
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 at 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 text 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 Board…
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.
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…
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 XI: Videos
Click the video title to view on YouTube where you’ll find a description and comments.
Andrew Huberman, PhD discusses post-finasteride syndrome on the Huberman Lab podcast
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 little-discussed in the literature: the role of the androgen dihydrotestosterone (DHT) in development throughout the lifespan. While we…
Regulators are waking from their slumber
Agencies in France, the United Kingdom, Canada and the United States are strengthening warnings about finasteride risks
A rundown of new bibliographies & research guides
The research base spans many disciplines and goes back almost 50 years. To help researchers get oriented, an on-ramp was added. In the Systems & functions area, a new bibliography was added: Adverse effects on skin, comprising nine case reports. The gynecomastia bibliography has been expanded. The bibliography on the musculoskeletal system has been expanded…
2022 – year in review
Regulators added warnings, the New York Post covered finasteride harms, and two influencers urged followers to avoid the drug.
Recent developments
In June 2022, the FDA required the addition of ‘suicidal ideation and behavior’ to the Propecia (finasteride 1 mg) label. In July, France’s national drug regulator ANSM added materials to help patients better understand the risks of finasteride.
Hair or manhood—choose one?
In ancient Greece, Hippocrates and Aristotle observed that eunuchs did not go bald. Jumping ahead to the early 1940s, American anatomist James B. Hamilton reviewed histories of men with testosterone deficiency and found a pattern: the earlier the age of hormone deficiency, the less balding occurred.
Musculoskeletal adverse events of finasteride
When men take finasteride for hair loss, their attention is directed to the hair and scalp. When adverse events (AEs) occur in other systems and areas of the body, it might not be obvious that finasteride could be the culprit. But the drug alters levels of chemical messengers in the blood as well as peripheral…
This site describes adverse experiences which some may find disturbing. See the Reader advisory.
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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