What role does SHBG play in weight loss?

SHBG (Sex Hormone-Binding Globulin) regulates the bioavailability of testosterone and estradiol. Low SHBG levels are associated with insulin resistance, metabolic syndrome, and obesity. Weight loss—especially through caloric restriction and exercise—can increase SHBG, which may improve insulin sensitivity. However, the evidence is largely observational; no robust RCTs demonstrate a causal role of SHBG in weight loss. Genetic variants in the SHBG gene have only small effects on SHBG levels. DNA tests claiming to personalize diet or exercise based on SHBG variants overstate the clinical relevance. The benefit of such tests is not supported by large intervention studies. SHBG is better viewed as a biomarker of metabolic health rather than a direct target for weight loss. Safety note: Men with low SHBG and symptoms of low testosterone should seek medical evaluation for possible hormone therapy—DNA tests are not a substitute for clinical assessment.