Which hormones are typically low in hypothyroidism?

In hypothyroidism, the thyroid gland is underactive and does not produce sufficient amounts of thyroid hormones, specifically triiodothyronine (T3) and thyroxine (T4). These hormones are crucial for regulating metabolism, energy levels, and overall metabolic processes in the body. When a patient has hypothyroidism, the levels of T3 and T4 are typically low because the thyroid is unable to produce them sufficiently.

The body usually responds to low levels of T3 and T4 by increasing the production of thyroid-stimulating hormone (TSH) from the pituitary gland in an attempt to stimulate the thyroid gland to produce more hormones. Therefore, while TSH might be elevated in hypothyroidism, both T3 and T4 will remain low.

This understanding highlights why the hormones T3 and T4 are specifically referenced as being low in the context of hypothyroidism. Other hormone levels mentioned in the other choices do not directly relate to the dysfunction of the thyroid in the same way as T3 and T4.