What role does FT4 play in blood sugar?

FT4 (free thyroxine) is a thyroid hormone that regulates basal metabolic rate and carbohydrate metabolism. It stimulates gluconeogenesis and glycogenolysis in the liver, which can raise blood glucose levels. In hyperthyroidism (high FT4), fasting blood sugar often increases and insulin resistance worsens. Conversely, hypothyroidism (low FT4) can reduce glucose production and increase hypoglycemia risk. The evidence for these effects is strong (human-strong), based on clinical studies and endocrine guidelines. However, FT4 is not a direct blood sugar regulator but acts indirectly via metabolism. MyBody-X does not currently list a specific FT4 test in its product catalog; if you want to assess thyroid function, consult a physician. Interpretation of FT4 in consumer tests is limited because many factors (medications, diet, time of day) affect values. An isolated FT4 without TSH and fT3 is of little diagnostic value. For abnormal blood sugar or thyroid symptoms, medical evaluation is essential.