Side Effects of 5-Alpha Reductase Inhibitors: A Comprehensive Review

May 2013 in “ Sexual medicine reviews ”

Landon Trost, Theodore R. Saitz, Wayne J.G. Hellstrom

TLDR 5-alpha reductase inhibitors slightly increase the risk of sexual and mood side effects, and breast growth in men.

The 2013 review analyzed the side effects of 5-alpha reductase inhibitors (5ARIs), such as finasteride and dutasteride, which are used to treat benign prostatic hyperplasia and androgenetic alopecia. The analysis included data from 62,827 patients and found slightly higher rates of adverse effects like decreased libido (1.5%), erectile dysfunction (ED) (1.6%), ejaculatory dysfunction (EjD) (3.4%), and gynecomastia (1.3%) compared to placebo. The review also noted concerns about the actual prevalence of these side effects and the possibility of persistent symptoms after stopping the medication. It concluded that while 5ARIs are associated with a small increase in the risk of sexual dysfunction, mood disorders, and gynecomastia, more research is needed to determine the true prevalence and persistence of these side effects.

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37 / 37 results

research Persistent Sexual Side Effects of Finasteride: Could They Be Permanent?

112 citations , November 2012 in “The Journal of Sexual Medicine”

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Rats had lasting erectile problems after stopping a certain medication.

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research Persistent Sexual Side Effects of Finasteride for Male Pattern Hair Loss

185 citations , June 2011 in “The Journal of Sexual Medicine”

Finasteride for hair loss can cause long-lasting sexual side effects like low libido and erectile dysfunction.

research Finasteride-Induced Secondary Infertility Associated with Sperm DNA Damage

36 citations , May 2011 in “Fertility and Sterility”

Finasteride use may cause sperm damage and infertility, stopping it can improve sperm health.

research Adverse Side Effects of 5α-Reductase Inhibitors Therapy: Persistent Diminished Libido, Erectile Dysfunction, and Depression in a Subset of Patients

223 citations , March 2011 in “The Journal of Sexual Medicine”

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Knowing about finasteride's sexual side effects increases reported dysfunction.

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23 citations , July 2007 in “Archives of Andrology”

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research The Effect of 5α-Reductase Inhibition with Dutasteride and Finasteride on Semen Parameters and Serum Hormones in Healthy Men

195 citations , May 2007 in “The Journal of Clinical Endocrinology and Metabolism”

Dutasteride and finasteride may reduce sperm count and volume but don't affect movement or shape; effects are reversible after stopping.

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Finasteride for hair loss has minimal impact on sexual function.

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research Marked Suppression of Dihydrotestosterone in Men with Benign Prostatic Hyperplasia by Dutasteride, a Dual 5α-Reductase Inhibitor

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Dutasteride more effectively lowers DHT levels in men with enlarged prostates than finasteride.

research Finasteride-Associated Male Infertility

34 citations , January 2004 in “Revista do Hospital das Clínicas”

Finasteride may worsen infertility in men with existing issues, but stopping it can improve sperm health.

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research Depression Related to Finasteride Administration for Androgenetic Alopecia

88 citations , October 2002 in “Journal of Dermatology”

Finasteride for hair loss may cause depression, affecting sleep and relationships.

research The Effects of Transdermal Dihydrotestosterone in the Aging Male: A Prospective, Randomized, Double-Blind Study

110 citations , April 2002 in “The Journal of clinical endocrinology and metabolism/Journal of clinical endocrinology & metabolism”

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research Evaluation of Sexual Function in Subjects Taking Finasteride for the Treatment of Androgenetic Alopecia

36 citations , September 2001 in “Journal of The European Academy of Dermatology and Venereology”

Finasteride doesn't reduce sexual function in people with hair loss.

research Chronic Treatment with Finasteride Daily Does Not Affect Spermatogenesis or Semen Production in Young Men

104 citations , October 2000 in “The Journal of Urology”

Finasteride doesn't harm male fertility or sperm quality, but may slightly reduce ejaculate volume.

research Dihydrotestosterone and the Concept of 5-Alpha-Reductase Inhibition in Human Benign Prostatic Hyperplasia

184 citations , January 2000 in “European Urology”

Blocking the enzyme that turns testosterone into DHT can safely and effectively treat enlarged prostate.

research Finasteride in the treatment of men with frontal male pattern hair loss

187 citations , June 1999 in “Journal of The American Academy of Dermatology”

Finasteride effectively treats frontal hair loss with few side effects.

research Finasteride in the treatment of men with androgenetic alopecia

581 citations , October 1998 in “Journal of The American Academy of Dermatology”

Finasteride safely and effectively treats male pattern hair loss, but may cause reversible sexual issues and harm male fetuses.

research Effects of the 5α-Reductase Inhibitor Finasteride on Serum Levels of Gonadal, Adrenal, and Hypophyseal Hormones and its Clinical Significance: A Prospective Clinical Study

56 citations , April 1998 in “Steroids”

Finasteride reduces hair loss and treats BPH without major hormone changes, but may cause sexual dysfunction.

research The Effect of Finasteride on the Risk of Acute Urinary Retention and the Need for Surgical Treatment among Men with Benign Prostatic Hyperplasia

1054 citations , February 1998 in “The New England Journal of Medicine”

Finasteride reduces urinary issues and surgery need in men with enlarged prostates by over 50%.

research The Efficacy of Terazosin, Finasteride, or Both in Benign Prostatic Hyperplasia

728 citations , August 1996 in “The New England Journal of Medicine”

Terazosin and finasteride effectively treat BPH, but combining them adds no extra benefit.

research The Effect of Finasteride in Men with Benign Prostatic Hyperplasia

1040 citations , October 1992 in “The New England Journal of Medicine”

Finasteride effectively treats BPH but may increase sexual dysfunction risk.

8 / 8 results

research Sexual Problems of Men With Androgenic Alopecia Treated With 5-Alpha Reductase Inhibitors

10 citations , April 2019 in “Sexual medicine reviews”

Men using hair loss drugs like finasteride may experience sexual side effects like erectile dysfunction, but it's unclear who will be affected and when. Treating depression and sexual symptoms is suggested, as these men often have higher rates of both. More research is needed to understand why these side effects occur.

research Adverse Side Effects of 5α-Reductase Inhibitors Therapy: Persistent Diminished Libido, Erectile Dysfunction, and Depression in a Subset of Patients

223 citations , March 2011 in “The Journal of Sexual Medicine”

Some patients taking finasteride or dutasteride may have ongoing sexual problems and depression even after stopping the medication.

research Finasteride in the Treatment of Androgenetic Alopecia

62 citations , April 2004 in “Expert Opinion on Pharmacotherapy”

Finasteride effectively treats male pattern baldness, improving hair growth and density.