What is the normal range for TSH levels in healthy adults?

The normal range for thyroid-stimulating hormone (TSH) levels in healthy adults is accurately represented by the range of 0.4 to 4.0 milli-international units per liter. TSH is a crucial hormone produced by the pituitary gland that stimulates the thyroid gland to produce thyroid hormones (T3 and T4), which are essential for regulating metabolism, energy production, and overall growth and development.

This range is widely accepted and is supported by various clinical guidelines. Values below 0.4 may indicate hyperthyroidism, where there is an overproduction of thyroid hormones, while values exceeding 4.0 could suggest hypothyroidism, where there is insufficient thyroid hormone production. It is important for clinicians to interpret TSH levels in the context of individual patient factors, including symptoms and possible underlying conditions, to ensure accurate diagnosis and management of thyroid disorders.