From the Guidelines
Exogenous testosterone does not have a direct, well-established effect on lowering Sex Hormone Binding Globulin (SHBG) levels as its primary mechanism of action, according to the most recent and highest quality studies available, which primarily focus on its impact on fertility and testosterone deficiency rather than SHBG levels directly. The provided evidence 1 discusses the effects of exogenous testosterone on fertility, testosterone deficiency, and the management of infertility in men, but it does not directly address the impact of exogenous testosterone on SHBG levels.
When considering the management of testosterone deficiency and infertility, it's crucial to understand the effects of exogenous testosterone on the body's natural hormone production and balance. Exogenous testosterone administration provides negative feedback to the hypothalamus and pituitary gland, which can result in inhibition of gonadotropin secretion, affecting spermatogenesis 1. For men interested in current or future fertility, testosterone monotherapy should not be prescribed due to its inhibitory effects on spermatogenesis 1.
The use of aromatase inhibitors, human chorionic gonadotropin, selective estrogen receptor modulators, or a combination thereof may be considered for infertile men with low serum testosterone, as these treatments aim to promote endogenous testosterone production and improve spermatogenesis 1. However, the direct effect of exogenous testosterone on SHBG levels is not a primary concern in these guidelines, which focus more on the management of testosterone deficiency and infertility.
In clinical practice, monitoring hormone levels, including total testosterone, free testosterone, and other relevant markers, is essential for ensuring proper hormone balance in patients undergoing testosterone therapy. However, the specific impact of exogenous testosterone on SHBG levels is not clearly outlined in the provided evidence, suggesting that this aspect may not be a primary consideration in the management of testosterone deficiency and male infertility.
Given the information available and prioritizing morbidity, mortality, and quality of life, the focus should remain on the appropriate management of testosterone deficiency and infertility, considering the effects of exogenous testosterone on natural hormone production and fertility potential, rather than its direct impact on SHBG levels.
From the Research
Effect of Exogenous Testosterone on SHBG
- The study 2 found that exogenous testosterone administration leads to a decrease in serum Sex Hormone-Binding Globulin (SHBG) levels, with a mean decrease of 62.18% +/- 8.85% from basal values.
- This decrease in SHBG levels is used as an indicator of androgen sensitivity in prepubertal subjects.
- In contrast, the study 3 found that clomiphene citrate therapy, which is used to treat male hypogonadism, leads to an increase in SHBG levels, in addition to increases in total testosterone, free testosterone, and other hormones.
- The study 4 investigated the pharmacokinetics of sublingual testosterone in healthy premenopausal women and found that SHBG levels influence the free and total levels of testosterone, but did not directly address the effect of exogenous testosterone on SHBG levels.
- The studies 5 and 6 focused on the treatment of male hypogonadism with human chorionic gonadotropin (hCG) and clomiphene citrate, and did not provide direct evidence on the effect of exogenous testosterone on SHBG levels.
Summary of Findings
- Exogenous testosterone administration has been shown to decrease SHBG levels in one study 2.
- Other studies have found increases in SHBG levels with clomiphene citrate therapy 3, but did not directly address the effect of exogenous testosterone on SHBG levels.
- The evidence suggests that exogenous testosterone may lower SHBG levels, but more research is needed to confirm this finding.