The metabolic syndrome (MS) -known also as "plurimetabolic" syndrome, syndrome of resistance to insulin or X syndrome - is a controversial clinical circumstance that appears with extensive phenotypic variations in people with an endogenous predisposition determined genetically and conditioned by environmental factors.

It is characterized by the presence of insulin resistance and compensating hyperinsulinism associated to disorders of the hydrocarbonate metabolism , elevated readings of arterial pressure, lipid alterations (hypertriglyceridemia), lowering of the cHDL, presence of LDL type B, increase of the free fatty acids and posprandial lipemia) and obesity, with an increase of morbimortality of atherosclerotic origin, although the absolute risk that comes with the metabolic syndrome has not yet been determined accurately in different populations.

Clinically the resistance to the insulin is defined as the incompetence of a determined concentration of insulin to control the glucose and, although is the pathophysiological base of the diabetes, would not bring together all the etiologic aspects in the MS.

It is a complex cell abnormality that fundamentally affects the adipose tissue, the liver and the skeletal muscle.