Evidence check: SHBG in the context of Sport

SHBG (sex hormone-binding globulin) is a carrier protein for testosterone and estradiol. In sports, SHBG is often discussed as a marker of hormonal balance and insulin sensitivity. Low SHBG levels are associated with metabolic syndrome, obesity, and insulin resistance—factors that can impair recovery and performance. Endurance training and a high-fiber, low-sugar diet tend to increase SHBG, while intense resistance training and high carbohydrate intake may lower it. However, the evidence is heterogeneous: many studies are small or limited to specific populations (e.g., men with metabolic syndrome). A direct causal link between SHBG and athletic performance has not been established. Moreover, SHBG is influenced by many factors (thyroid hormones, cortisol, liver function, genetics), so a single measurement without clinical context has limited value. For athletes, SHBG testing is only useful when accompanied by symptoms such as loss of libido, fatigue, or unexplained performance decline—and interpretation should be done by an endocrinologist. MyBody-X offers SHBG as part of metabolic panels but highlights these limitations. Evidence: mechanistic, moderate.