The Effect of 5-α Reductase Inhibitor on Male Reproductive Function

madman

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Abstract

Introduction


5α-reductase inhibitor (5-ARI) such as finasteride or dutasteride has been approved to treat benign prostatic hyperplasia and androgenic alopecia (male pattern hair loss), which blocks the conversion of testosterone to dihydrotestosterone. With expanding usage among young men, concerns exist regarding potential negative influence of this hormonal agent on male reproductive function.


Objective

We investigated the effect of 5-ARI usage on the sexual and reproductive function in men of reproductive age.


Methods

This study included healthy males of reproductive age who visited single fertility center. We compared the sexual and reproductive function between those who take 5-ARI for androgenic alopecia (n=40) and no medication group (n=48). Erectile function was surveyed using IIEF-5 questionnaire. In addition to basic fertility evaluation, semen parameters, and serum reproductive hormone were compared between groups. Semen samples were collected with abstinence period of more than 48 hours. Patients with chronic medical disease, previous scrotal surgery, or exposure to gonadotoxic agents were excluded.


Results

The mean duration of 5-ARI intake was 54.2 months and there was no significant difference in IIEF-5 score between the two groups (5-ARI group vs. control group). There was no significant difference in semen parameters; sperm concentration ([101.5 ± 68.7]×10^6/mL vs. [97.5 ± 65.5]×10^6/mL, p=0.783), sperm motility (39.8% ± 9.0% vs. 42.0% ± 8.5%, p=0.224), sperm progressive motility (37.4% ± 9.4% vs. 39.0% ± 9.0%, p=0.404), sperm morphology (normal forms: 4.5% ± 1.4% vs. 4.8% ± 1.1%, p=0.308), except smaller semen volume in 5-ARI group (2.3 ± 0.9 mL vs. 3.4 ± 1.4 mL, p<0.001). Serum testosterone and FSH were higher in 5-ARI group. Two patients experienced adverse events while taking 5-ARI.


Conclusions

Our study suggests that administration of 5-ARI does not significantly affect male reproductive function. However, a prudent approach is recommended in men with oligospermia or ejaculatory dysfunction.
 

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Understanding Your Hormones

Estradiol (E2)

A form of estrogen produced from testosterone. Important for bone health, mood, and libido. Too high can cause side effects; too low can affect well-being.

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Dihydrotestosterone is a potent androgen derived from testosterone. Affects hair growth, prostate health, and masculinization effects.

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The biologically active form of testosterone not bound to proteins. Directly available for cellular uptake and biological effects.

Scientific Reference

Lakshman KM, Kaplan B, Travison TG, Basaria S, Knapp PE, Singh AB, LaValley MP, Mazer NA, Bhasin S. The effects of injected testosterone dose and age on the conversion of testosterone to estradiol and dihydrotestosterone in young and older men. J Clin Endocrinol Metab. 2010 Aug;95(8):3955-64.

DOI: 10.1210/jc.2010-0102 | PMID: 20534765 | PMCID: PMC2913038

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