Myths vs facts: SHBG and Fruchtbarkeit

SHBG (sex hormone-binding globulin) is frequently discussed in fertility contexts, but myths and facts are often mixed. Fact: SHBG binds sex hormones, regulating free testosterone and estradiol. Low SHBG—common in insulin resistance, obesity, and PCOS—can increase free androgens and impair fertility. Myth: High SHBG is always beneficial. In reality, very high SHBG (e.g., in hyperthyroidism or liver disease) can reduce free hormone availability and also disrupt fertility. Myth: SHBG alone determines fertility. Fertility depends on multiple factors (hypothalamic-pituitary-gonadal axis, oocyte/sperm quality). SHBG is a marker, not a direct cause. Caveat: Evidence is observational; individual SHBG levels must be interpreted alongside insulin resistance, thyroid function, and lifestyle. Genetic testing for SHBG variants (e.g., rs1799941) does not provide clinically actionable fertility guidance without accompanying hormone and metabolic workup.