What is the significance of a Sex Hormone Binding Globulin (SHBG) level of 53 nanomoles per liter (nmol/L), within the reference range of 18-130 nmol/L?

From the Guidelines

Your Sex Hormone Binding Globulin (SHBG) level of 53 nmol/L is within the normal reference range of 18-130 nmol/L, indicating healthy hormone transport function. No specific treatment or intervention is needed for this result. SHBG is a protein produced primarily by the liver that binds to sex hormones like testosterone and estrogen in the bloodstream, regulating their bioavailability to tissues. Normal SHBG levels suggest your body is appropriately managing the transport and delivery of these hormones. Various factors can influence SHBG levels, including liver function, thyroid hormones, insulin levels, and certain medications, as noted in the context of obesity-related decreases in testosterone being frequently attributable to low concentrations of sex hormone-binding globulin 1. If you're monitoring SHBG as part of hormone therapy or for a specific condition, continue your current management plan as this result doesn't indicate any need for adjustment. Regular follow-up with your healthcare provider is recommended if you're being treated for any hormone-related conditions, even with this normal result. In the context of hypogonadism, particularly in men with obesity, assessing SHBG levels is crucial, alongside total and free testosterone levels, to understand the underlying cause of low testosterone, as guided by the practical use of pharmacotherapy for obesity 1. However, given your SHBG level is within the normal range, there's no immediate indication for testosterone replacement therapy or other interventions based solely on this result. It's essential to consider symptoms and other hormone levels, such as total and free testosterone, as part of a comprehensive evaluation for hypogonadism, especially in men with obesity, where low SHBG can lead to low total testosterone but normal free testosterone levels 1. Monitoring and management should be individualized, focusing on overall hormone balance and health status rather than SHBG levels alone.

From the Research

Sex Hormone Binding Globulin (SHBG) Levels

• The provided SHBG level is 53 nmol/L, which falls within the reference range of 18-130 nmol/L.
• According to the study 2, SHBG levels are influenced by thyroid hormones and can be used as a marker of thyroid hormone effect at the peripheral tissue level.
• The study 3 found that SHBG levels are usually elevated in thyrotoxicosis and can be used as an index of thyroid hormone action.

Relationship with Thyroid Hormones

• The study 2 found that SHBG levels are elevated in overt hyperthyroidism and decreased in manifest hypothyroidism.
• The study 3 found that basal serum SHBG values are correlated with free T4 index (FT4I) values, and that SHBG levels increase in response to T3 administration in individuals with normal tissue responsiveness.

Clinical Significance

• The study 4 found that SHBG concentrations vary widely in younger and older men, and that this variability can impact the interpretation of test results for hormones that bind to SHBG, such as testosterone.
• The study 5 found that SHBG levels are associated with disease severity and prognosis in men with chronic heart failure, and that high SHBG levels are associated with an increased risk of cardiac death.

SHBG Levels in Different Populations

• The study 4 found that mean SHBG levels are significantly higher in older men (36.6±15.8 nmol/L) compared to younger men (27.7±13.3 nmol/L).
• The study 5 found that the median SHBG level in men with chronic heart failure is 34.5 nmol/L, and that high SHBG levels are associated with an increased risk of cardiac death.