Can SHBG help with Sport?

SHBG (sex hormone-binding globulin) modulates the bioavailability of free testosterone and estradiol. Lower SHBG can increase free testosterone, which may theoretically support muscle growth and recovery. However, direct evidence that manipulating SHBG improves sports performance is weak and inconsistent. SHBG levels are influenced by diet (e.g., carbohydrate intake), body fat, insulin resistance, and genetic variants (e.g., in the SHBG gene). Very low SHBG may signal metabolic issues like insulin resistance. Consumer DNA tests often report SHBG-related SNPs, but effect sizes are small and not actionable for most athletes. Without medical supervision, attempting to alter SHBG is not recommended. Evidence: human-moderate (observational studies), not strong interventional. Caveat: lifestyle and training matter more than SHBG alone.