The Post-Finasteride Syndrome Foundation is dedicated to helping fund research on the characterization, underlying biologic mechanisms and treatments of the post-finasteride syndrome (PFS). A secondary goal is to help increase public awareness of PFS.

Often life-altering, PFS is characterized by devastating sexual, neurological, and physical side effects that persist in men who have taken the 5-alpha reductase type II enzyme inhibitor finasteride.

Finasteride is prescribed for the treatment of hair loss under the brand name Propecia (and generics) and for the treatment of enlarged prostate under the brand name Proscar (and generics).


Post Finasteride Syndrome

Among the most common finasteride side effects being reported to health agencies are loss of libido, erectile dysfunction, orgasm disorders, depression, Peyronie’s disease and abnormal breast enlargement. Unfortunately for some men, such side effects can persist for months or even years after stopping the drug. [more...]


Post Finasteride Syndrome Research

The PFS Foundation’s primary objective is to help establish medical consensus and acceptance of PFS by promoting scientific and clinical research. Research initiatives focus on uncovering underlying biologic mechanisms for the syndrome and its persistent side effects at a molecular level. [more...]


Post Finasteride Syndrome Publications

As media awareness and scientific interest in PFS continues to grow, the PFS Foundation will serve as a central resource for published research on the condition. We aim to facilitate collaborative efforts amongst health care professionals and leading scientists worldwide.  [more...]

Medical Awareness


Available toxicity information from clinical trials of finasteride in men with [androgenic alopecia] is very limited, is of poor quality, and seems to be systematically biased. In a cohort of men prescribed finasteride for routine treatment of AGA, most would have been excluded from the pivotal studies that supported US Food and Drug Administration approval for AGA. Published reports of clinical trials provide insufficient information to establish the safety profile for finasteride in the treatment of AGA.

Adverse Event Reporting in Clinical Trials of Finasteride for Androgenic Alopecia: Steven M. Belknap, MD. JAMA Dermatology, April 1, 2015


A.M. Traish
The argument that the benefits of [finasteride] outweigh the risks is slowly eroding in the face of new emerging scientific evidence from preclinical and clinical studies. The available data demonstrate that such drugs do pose serious adverse effects, especially in a subset of men who may have the predisposition to be affected severely… Physicians need to be aware of the adverse side effects of these drugs and are encouraged to share this information with their patients prior to commencing therapy with finasteride.

A.M. Traish, Prof. of Biochemistry and Urology, Boston University School of Medicine


Christine A Ganzer
In this pilot study, we sought to characterize sexual and nonsexual adverse effects that men reported experiencing at least 3 months after stopping the medication… Responses from 131 generally healthy men (mean age, 24 years) who had taken finasteride for male pattern hair loss was included in the analysis. The most notable finding was that adverse effects persisted in each of the domains, indicating the possible presence of a “post-finasteride syndrome.”

Christine A Ganzer, PhD, Assistant Professor, City University of New York


Post-finasteride syndrome is now a recognized condition, affecting as many as 20 per cent of those taking finasteride… 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 effects of finasteride, while others—the majority—are not affected… Further research is needed on who is susceptible to the persistent, adverse side-effects of finasteride and on the underlying mechanisms of the medication.

Andrew Rynne, MD, Clane General Hospital, Kildare, Ireland


Treatment of young subjects is of increasing concern due to accumulating evidence that daily use of oral finasteride has several severe adverse effects… Since finasteride inhibits T conversion into DHT, which is responsible for most androgen activity, it is plausible that prolonged finasteride use in predisposed individuals could simulate the effects of aging in young men. Since some of the effects of androgen inhibition cannot be reversed once local androgen levels are re-established, it is temping to speculate that patients could still suffer from adverse sexual effects several months or even permanently after finasteride discontinuation.

Carla Di Loreto, Department of Medical and Biological Sciences, School of Medicine, University of Udine, Udine, Italy


Persistent adverse effects of finasteride in younger men include erectile dysfunction, low libido, lack of orgasms, depression, and decreased alcohol consumption. One study has found lower levels of several neurosteroids in this population. Out of the various persistent side effects, erectile dysfunction and decreased alcohol consumption 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.

Michael S. Irwig, MD, Associate Professor of Medicine, Director of Andrology, George Washington University


Donatella Caruso
Observations performed in a subset of patients treated for male pattern hair loss indicate that persistent sexual side effects as well as anxious/depressive symptomatology have been reported even after discontinuation of finasteride treatment.

Donatella Caruso, Associate Professor, Department of Pharmacology and Biomolecular Sciences, University of Milan


Finasteride is a steroid 5-alpha-reductase inhibitor, approved for the treatment of androgenetic alopecia and benign prostate hyperplasia. In some patients the treatment is associated with adverse side effects that could become persistent after therapy discontinuation, resulting in the so-called post-finasteride syndrome (PFS).

Erika Cecchin, PhD, Experimental and Clinical Pharmacology Unit CRO National Cancer Institute, Pordenone, Italy




Our research definitely concludes that PFS is real. For a subset of these men, the damage persists — maybe forever — even after they go off the drug. We don’t fully understand why, but it is as if something shuts off biologically, and stays that way.

A.M. Traish, Prof. of Biochemistry and Urology, Boston University School of Medicine


Irwin Goldstein
We are becoming more and more aware of persistent sexual health problems occurring as a result of the use of 5-alpha reductase inhibitors, finasteride, and dutasteride, in a subset of patients. What is even more alarming is that in addition to persistent sexual issues, there are persistent central cognitive issues and concerns of persistent depression.

Irwin Goldstein, MD, Editor-in-Chief of the Journal of Sexual Medicine