Background: The metabolic syndrome and thyroid dysfunctions are the two most prevalent endocrine illnesses, and they significantly overlap. Due to their strong associations with morbidity and mortality, both have a huge global influence on health care. Insulin resistance (IR) is a primary component of metabolic syndrome (MetS), a collection of disorders related to metabolism. The management and maintenance of cellular energy balance depend on thyroid hormones (TH). Both the central nervous system and TH's direct connection with peripheral target organs serve as mediating mechanisms for these activities. Recently, there has been discussion on the potential link between MetS and its constituent parts and changes in the morphology and function of the thyroid gland. Studies concentrating on TNs' risk factors are required because of the disease's significant morbidity.

Aim: To summarize recent developments in the association of thyroid function with metabolic syndrome (MetS).

Conclusion: Thyroid stimulating hormone, free T3, free T4, and metabolic parameters have a complex relationship that may be influenced by inflammatory markers, age, sex, BMI, insulin resistance, smoking, iodine intake, and other factors.