Hormones, Age, and Erectile Dysfunction: Should Routine Testing Be Part of the Initial Evaluation?

Background/Objectives: The aim of this study was to investigate the relationship between age, the severity of erectile dysfunction (ED), and the various hormones that may influence erectile function. Methods: A multicenter cross-sectional study was conducted between January 2015 and December 2023. The study assessed age, sexual function using the IIEF-15 questionnaire, and the levels of total testosterone (TT), free testosterone (FT), FSH, LH, estradiol, prolactin (PRL), and SHBG. Results: A total of 411 patients were included in the study. The mean age of the patients was 63.19 years. The vast majority (91.73%) exhibited some degree of ED. The severity of ED increases with age, ranging from 56.26 years for patients without ED to 73.12 years for those with severe ED. A statistically significant negative correlation was observed between IIEF and age, while a positive correlation was observed between IIEF and serum levels of TT and FT (p < 0.05). Age was significantly correlated with all evaluated hormones (p < 0.01), except estradiol and prolactin. Total testosterone levels progressively decreased with the increase in the severity of erectile dysfunction, from a median of 7.05 ng/mL in patients with normal erectile function to 3.56 ng/mL in those with severe symptoms, remaining above the normal minimum threshold across all groups, whereas free testosterone (FT) levels also declined progressively. All erectile dysfunction groups had median FT levels below the normal minimum threshold. FSH, LH, and SHBG showed an increase with each progressive severity of erectile dysfunction. The multivariate linear regression revealed that IIEF scores are significantly associated with age, TT, and FT levels, while FSH did not present a statistically significant association in this model. Conclusions: Age shows a significant statistical correlation with both the severity of erectile dysfunction and the levels of total testosterone, free testosterone, LH, FSH, and SHBG. Total and free testosterone levels are significantly associated with the severity of erectile dysfunction, with free testosterone median values remaining above the normal minimum threshold in all patients with erectile dysfunction. Therefore, free testosterone should be considered a routine test, alongside total testosterone. In contrast, LH, estradiol, SHBG, and prolactin do not demonstrate any statistical correlation with erectile dysfunction and should not be recommended as routine investigations.