Is SHBG useful for fatigue?

SHBG (sex hormone-binding globulin) is sometimes discussed in hormone and metabolic contexts, but direct evidence for its usefulness in fatigue is weak. The provided context does not mention SHBG. In general medicine, SHBG is not a standard biomarker for fatigue. Low SHBG can indicate insulin resistance or metabolic syndrome, which may indirectly relate to tiredness, but no RCTs or clinical guidelines support SHBG testing for fatigue diagnosis. Fatigue has many causes (iron deficiency, thyroid issues, sleep disorders, mental health), and SHBG alone cannot differentiate them. Ordering an SHBG test without a specific clinical indication is not evidence-based. Caveat: Not clinically validated for fatigue. Evidence grade: unclear/marketing.