Men who previously took finasteride and dutasteride have reported sexual dysfunction, anxiety, depression, cognitive problems and other dysfunctions which have continued long after stopping the drug. This paper proposes an explanation for how these dysfunctions may develop.
This post responds to a recent research letter: Nguyen DD, et al. Disproportional signal of sexual dysfunction reports associated with finasteride use in young men with androgenetic alopecia: A pharmacovigilance analysis of VigiBase. J Am Acad Dermatol. 2022. doi:10.1016/j.jaad.2022.03.037 A recent paper by Nguyen et al. in the Journal of the American Academy of Dermatology analyzes sexual adverse … Read more
A thread originally posted on Twitter is reproduced below. For an in-depth version, see the essay Context matters. See also a critique of three previous papers with similar designs, findings and conclusions. Twitter thread Nguyen et al, 2022 is the fourth analysis of adverse events of finasteride to appear since 2018. All four studies play … Read more
Although finasteride came on the market in the 1990s, the science that led to its development began two decades earlier. The rationale for the drug emerged from a study of a unique group of people in a remote village in the Dominican Republic called Las Salinas. Locals there have long known about children who follow … Read more
Highlights Estimated Propecia revenue from 1999–2015: $5.2 billion Rough estimate of operating profit from Propecia: $4.2 billion Merck received FDA approval for Propecia (finasteride 1 mg/day) in December 1997. Sales in the first year of marketing were reported to be $76 million. The peak years were 2010–2011, when Merck reported $447 million in Propecia sales … Read more
Since 1994, Merck has been aware of unresolved sexual dysfunction in men who stopped taking finasteride
Six months after discontinuing a Phase 3 finasteride trial, a man’s sexual adverse experience was unresolved. There were also 16 men whose drug-related sexual adverse experiences were unresolved at the conclusion of the trial.
Filings from lawsuits alleging persistent adverse effects of Propecia and Proscar in various jurisdictions in the United States and Canada, dating from 2011 to 2021.
The Merck files, part 2: Merck responds to regulatory concerns about persistent adverse effects of Propecia
These documents from 2006–2009 concern Merck’s response to postmarketing reports of persistent erectile dysfunction, male infertility and depressive disorders, among other adverse events, associated with use of finasteride. In 2006, the Swedish Medical Products Agency asked Merck for an analysis of all adverse events affecting the male reproductive system which persisted after stopping Propecia. In … Read more
Merck first developed finasteride for benign prostatic hyperplasia, a condition typically found in men aged 55 and older. After receiving approval for the application in 1992 and bringing the drug to market as Proscar, Merck decided to seek approval of finasteride for male pattern hair loss—to be branded as Propecia. In a 1994 memo below, … Read more
Selected documents from Propecia litigation were released by court order in 2021. This series walks through these documents, revealing Merck’s strategy for discounting safety concerns arising from clinical trials and adverse event reports. The collection is divided into three parts: 1. An inside look at the development of Propecia (1994–2001) 2. Merck responds to regulatory … Read more
Those who have lasting dysfunctions after taking finasteride or dutasteride are not the only ones whose lives have been altered for the worse because of a medical treatment. This post summarizes diseases and conditions that may arise from medical treatments: five in dermatology, four in psychiatry and one in general medicine. ↓ Jump to the … Read more
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 finasteride 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 symptom / clinical presentation.
- Firsthand experiences of finasteride — Volume IV: FOIA edition
- Adverse events reported to FDA, 2018–2020
- A history of changes to the Propecia label
- ‘Safe and well-tolerated’: Arguments used to discredit reports of persistent adverse effects
- Commentary: Finding the occasion to talk about persistent adverse effects of finasteride
- Research: Adverse effects of finasteride on semen, sperm and fertility
- Research on lasting dysfunctions after taking finasteride or dutasteride
5-AR deficiency Adverse effects Adverse event reports Animal studies Antidepressants Anxiety Bibliography Bibliometrics Business Clinical trials Commentary Conflict of interest Cosmetic dermatology Denial and skepticism Dermatologists Dermatology Doctor views Documents Drug label Etiopathology Europe FDA Firsthand reports Fluoroquinolones FOIA requests History Iatrogenic harm Litigation Merck Merck files PD-5ARI Penile abnormalities Persistent adverse effects Pharmacovigilance Post-finasteride syndrome Propecia Psychiatry Psychological adverse effects Recoveries Research Revenue Sexual adverse effects Sexual dysfunction SSRIs Vigibase