Is LDL useful for fatigue?

LDL (low-density lipoprotein) is a well-established risk marker for cardiovascular disease, but it is not a direct indicator of fatigue. Current evidence does not support using LDL as a standalone biomarker for exhaustion or tiredness. Fatigue is typically multifactorial, involving sleep, stress, nutritional deficiencies (iron, B12, vitamin D), thyroid function, and inflammation. While elevated LDL can be part of metabolic syndrome—which may indirectly correlate with fatigue—the evidence is weak and mechanistic. Genetic variants like APOA5 rs662799 affect triglycerides, not LDL directly, and have small effect sizes. Therefore, measuring LDL alone is not useful for fatigue assessment. A comprehensive workup including iron status, vitamin levels, thyroid panel, and inflammatory markers is recommended. Evidence level: unclear/mixed due to lack of direct studies linking LDL to fatigue.