Estrogens in Men: Clinical Implications for Sexual Function and the Treatment of Testosterone Deficiency

ABSTRACT Introduction The role of estrogens in male sexual function and the pathogenesis of testosterone deficiency remain controversial and poorly understood. Aims To review the distribution of estrogens in normal and testosterone deficient men, their potential role in sexual function, and the clinical implications of elevated estrogens during testosterone therapy. Methods A comprehensive, broad-based literature review was conducted on the role of estrogens in male sexual function and testosterone deficiency. Results Estrogens elicit a variety of physiological responses in men and may contribute to modulation of sexual function. In the absence of testosterone deficiency, elevations in estrogens do not appear to be harmful and estrogens may help maintain some, but not all, sexual function in castrated men. While the therapeutic use of estrogens at pharmacologic doses has been used to suppress serum testosterone, naturally occurring elevations of estrogens do not appear to be a cause of low testosterone. During testosterone replacement, estrogens may rise and occasionally reach elevated levels. There is a lack of evidence that treatment of elevated estrogen levels during testosterone replacement has benefit in terms of male sexuality. Conclusions Further research on the importance of estrogens in male sexual function is needed. Current evidence does not support a role of naturally occurring estrogen elevations in testosterone deficiency or the treatment of elevated estrogens during testosterone therapy.