What role does SHBG play in fatigue?

SHBG (sex hormone-binding globulin) is a carrier protein that binds testosterone and estradiol, regulating their free, bioactive fractions. Elevated SHBG can reduce free testosterone, which in men is linked to fatigue, low libido, and reduced energy. However, the evidence for a direct causal role of SHBG in fatigue is limited: SHBG levels are influenced by insulin resistance, liver function, thyroid status, and diet. High SHBG (e.g., in hyperthyroidism or liver disease) may indirectly contribute to fatigue via low free hormone availability. Conversely, low SHBG (e.g., in obesity or insulin resistance) is associated with metabolic disturbances that can also cause tiredness. The MyBody-X Body-Balance Check includes SHBG as part of a hormonal panel, but interpretation requires the full context (total/free testosterone, prolactin, albumin). Fatigue is multifactorial – poor sleep, stress, nutrient deficiencies, or psychological factors are often more impactful. A single SHBG value alone does not explain fatigue. Evidence: mechanistic; no strong clinical data supporting SHBG as a standalone fatigue marker.