How are SHBG and fertility related?

SHBG (sex hormone-binding globulin) binds testosterone and estradiol, controlling their free, active fractions. Low SHBG is linked to insulin resistance and PCOS, impairing female fertility. In men, high SHBG can reduce free testosterone, potentially affecting libido and sperm production. Evidence is observational and moderate; no large RCTs confirm causality. Direct-to-consumer blood or genetic tests may report SHBG-related variants, but effect sizes are small and not clinically predictive. Lifestyle factors (diet, exercise, body weight) have a stronger impact on SHBG levels than common genetic markers. Do not interpret SHBG results in isolation—consult a reproductive specialist for a full hormone panel and clinical assessment.