What happens to the TSH levels and TH levels when a person has hypothyroidism?

In hypothyroidism, the levels of thyroid hormones (T3 and T4) are low due to an underactive thyroid gland. In response to this deficiency, the pituitary gland produces more thyroid-stimulating hormone (TSH) to stimulate the thyroid to produce more hormones. Consequently, TSH levels are elevated in individuals with hypothyroidism. This combination of low thyroid hormone levels and high TSH is a key indicator of the condition.