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HomeHealth articlespost finasteride syndromeWhat Is Post Finasteride Syndrome ?

Post Finasteride Syndrome - An Overview

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Post-finasteride syndrome (PFS) is an array of adverse side effects that persist for at least three months after discontinuing the Finasteride drug.

Medically reviewed by

Dr. Dhananjay Tiwari

Published At March 27, 2023
Reviewed AtDecember 29, 2023


Adverse side effects from pharmacological drugs are, unfortunately, quite common. Therefore, this article focuses on the adverse events of Finasteride drug even after ceasing drug usage. Finasteride is a class of medication used to treat male pattern hair loss (gradually thinning of scalp hair, resulting in receding hairline or top of the head bolding) and in high doses in case of benign prostatic hyperplasia (enlarged prostate glands), in which finasteride used to relieve symptoms of frequent and difficult urination.

What Is The Mechanism of Action of Finasteride?

The mechanism of action of Finasteride is by lowering dihydrotestosterone levels, a male sex steroid. Finasteride inhibits the enzyme called 5alpha reductase, which plays a key role in the activation of neuroactive steroids such as progesterone and testosterone, which can further metabolize into dihydrotestosterone and dihydro-progesterone. Increased dihydrotestosterone levels cause the prostate to grow and hair loss in males. Thus Finasteride works by lowering the level of this steroid in the blood.

What Is Post-Finasteride Syndrome?

PFS is a rare condition that men experience after taking Finasteride (Proscar, Propecia). Patients of PFS suffer from persistent sexual, physical, and mental health adverse side effects that continue even after stopping the medication. Studies suggest it tends to occur in susceptible people, even if it is used in small doses, and for a short time, symptoms may persist for a long period. Based on currently available data, careful and individual assessment is required for using Finasteride drugs in a person with a history of infertility, sexual dysfunction, and depression. Nevertheless, it is pertinent to highlight that larger adequate cohort studies are not done, and many of these studies are devoid of long follow up of the patients suffering from PFS and the specific symptoms.

What Are the Symptoms of PFS in Males?

Symptoms of PFS include persistent sexual, physical, and neuropsychiatric adverse reactions. Mainly sexual functions are the most affected domains. Sexual functions are an integral part of men's lives, and dysfunction reduces the quality of life and interpersonal relationships with partners. At the same time, psychological disorders may worsen a person's social and personal life.

1) Finasteride and Sexual Adverse Effects:

  • The decline in sex drive.

  • Loss or no reaction to the sexual stimulations.

  • Erectile dysfunction.

  • Loss of pleasure or no feeling of orgasm.

  • Decrease in ejaculated volume and force.

  • Poor semen quality and infertility.

  • Penile sensitivity reduction.

  • Penis shrinkage.

  • Testicular atrophy (hypogonadism).

  • An abnormal curve in the penis (Peyronie's disease).

  • Testicular pain.

  • Gynecomastia (Enlarged breast).

2) Finasteride and Physical Adverse Effects:

  • Muscle stiffness.

  • Chronic fatigue.

  • Muscle cramps.

  • Tremors.

  • Skin rash.

  • Metabolic abnormalities.

3) Finasteride and Psychiatric Adverse Effects:

Preclinical studies have demonstrated a persistent alteration in neuroactive steroid level, a key regulator of nervous functions in patients taking Finasteride drugs even after cessation. Li et al. showed that Finasteride treatment also inhibits open-field behaviors and reduces the contents of dopamine and related metabolites in the central nervous system. In addition, Devoto et al. showed that Finasteride treatment also impairs the signaling of dopamine. Thus dysregulation of the dopamine system created by Finasteride may give rise to major depressive disorders and other symptoms such as,

  • Mental cloudiness (forgetfulness).

  • Slow thinking.

  • Depression.

  • Suicidal thoughts.

  • Emotional detachment.

  • Elevated anxiety.

  • Panic attacks.

  • Insomnia.

  • Slurred speech.

What Are the Finasteride Adverse Effects on Women?

FDA (food and drug administration) has approved Finasteride as a treatment of alopecia only in men. However, this drug is also increasingly used in women to treat hair loss patterns.

Wu et al., Shum et al., Valsecchi et al., and Yeon et al. showed adverse effects in females as follows;

  • Abortion induction.

  • Spontaneous abortion.

  • Maternal drug affecting the fetus.

  • Uterine cervix stenosis.

  • Menstruation irregularity.

  • Menorrhagia.

  • Endometrial hypertrophy.

  • Phalangeal agenesis.

  • Fatigue.

  • Arthritis.

  • Decreased libido.

  • Gastrointestinal discomfort.

Finasteride treatment in pregnancy is forbidden. Therefore, careful contraception is strongly recommended during finasteride treatment.

When to Get Help?

Consider that sexual adverse side effects are very common while taking Finasteride, but if these symptoms persist despite cessation for more than three months, this could be a sign of PFS.

Inform your healthcare provider of the symptoms you are suffering.

How Is the PFS Diagnosed?

Genetic determinants and molecular mechanisms behind Finasteride's adverse effects are poorly explored in patient and animal models. PFS symptoms, especially sexual and psychiatric, are mainly based on the patient's self-reporting. Thus diagnosis is mainly based on the history of Finasteride drug intake and the patient’s experienced symptoms.

How Is PFS Treated?

Unfortunately, no definitive treatment is still available for PFS. Discussing your symptoms with your health care provider is helpful as he may give you symptomatic relief therapy for a few symptoms.

Preventive Tips:

Prevention is always better than cure, especially in conditions like this, where so little is known about the causative mechanism of the condition. Therefore, lack of definitive treatment modalities is there. Avoiding the use of this drug in persons inclined towards mental disorders and sexual dysfunction is the key to the prevention of PFS.


It is important to note that the incident and prevalence of persistent Finasteride-related adverse reactions have never been proven and that the scientific community still needs to be fully recognized by PFS. Despite having characteristic and homogenous symptoms, the literature does not allow confirming PFS as a nosological ( the medical science branch that handles the classification of diseases) entity. Hence, it is essential to create practical advocacy regarding the patient's eligibility for the treatment with Finasteride and counsel these persons on possible risks and alternative drugs for treating their conditions and how you should proceed in case of side effects. Today there is no known cure or effective management for PFS, but medical societies are recently decerning the burden and scope of the problem.

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Dr. Dhananjay Tiwari
Dr. Dhananjay Tiwari

General Practitioner


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