Research responses

Below are responses by the Finasteride Watch editor to peer-reviewed research on harms of finasteride and dutasteride.

Some responses have also been posted on PubPeer:


  • Reckoning with underreporting—response to Lauck et al, 2024

    We do not know if the medical records used in this study are sensitive to sexual dysfunction in healthy men, and especially in men taking these drugs for hair loss. Since the study includes men taking 5-ARIs, the results do not shed light on why sexual dysfunction might persist after stopping these drugs.


  • Against armchair medicine: a retort to skeptical physicians

    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.


  • 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…


  • 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…


  • 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.


  • 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.


  • Meta-analysis launders safety data from old pharma trials; blames patients for drug harms

    Despite serious methodological shortcomings—including the preposterous use of on-drug safety data as a proxy for a post-drug condition—the authors nevertheless blame the post-drug syndrome on patient shortcomings. Zhang et al. have yoked bad logic to biased data in order to deflect attention away from drug harms.


  • Context matters: a rebuttal to yet another analysis of adverse events of finasteride

    This post responds to a recent research letter: Disproportional signal of sexual dysfunction reports associated with finasteride use in young men with androgenetic alopecia: a pharmacovigilance analysis of VigiBase.


  • A tweeted rebuttal to yet another analysis of finasteride adverse events

    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…


  • Tapped by Merck for litigation defense, a physician-researcher sowed doubts about finasteride harms

    A 2018 article disclosed that Dr. Kevin McVary had been retained as an expert for Merck’s defense in litigation regarding persistent adverse effects (AEs) of finasteride.1 Dr. McVary has also been relatively active as a contributor of three conference abstracts, an original article, an expert review, a quote in a media story and a symposium presentation…


  • Responding to a literature of doubt: limitations of three studies of adverse events of finasteride and dutasteride

    A fourth study has been published in the ‘literature of doubt’. Read the rebuttal. Background on the co-author of Baas et al, 2018 with a disclosed conflict of interest is here. Three studies analyzing adverse event (AE) data related to finasteride and dutasteride were published from 2018–2020 (the “AE papers”).1–3 The first to appear, by Baas…


  • ‘Safe and well-tolerated’: Arguments used to discredit reports of persistent adverse effects

    Summary It cannot simultaneously be true that finasteride is considered “safe” as a treatment for male pattern hair loss and that the drug causes severe and permanent sexual dysfunction in some men. Since 2011, dozens of papers have investigated its adverse effects, with some concluding that finasteride is safe for treating hair loss despite complaints…