Thyroid Panel

Thyroid-stimulating hormone — the standard screening test. But TSH only tells your brain's request for thyroid hormone, not how much your body actually has available. "Normal" range is debated; many functional practitioners use 0.5-2.5 as optimal.

Thyroid peroxidase and thyroglobulin antibodies detect Hashimoto's thyroiditis — the most common cause of hypothyroidism in women. Antibodies can be elevated 7-10 years before TSH becomes abnormal.

The unbound, available form of thyroxine — the storage hormone your thyroid produces. Low Free T4 with normal TSH can indicate early thyroid failure or poor production.

Total triiodothyronine — measures all T3 in your blood (bound and unbound). Useful for assessing overall T3 production and identifying T4-to-T3 conversion problems.

The most potent thyroid hormone and the form your cells actually use. Low Free T3 with normal TSH and T4 is extremely common in women and causes classic hypothyroid symptoms that get dismissed.

An inactive form of T3 that blocks thyroid hormone receptors. Produced in excess during chronic stress, inflammation, dieting, or illness. High Reverse T3 explains why you feel hypothyroid despite "normal" labs.

Essential for the enzyme that converts T4 to active T3. Selenium deficiency impairs thyroid function and is also critical for reducing thyroid antibodies in Hashimoto's.

The building block of thyroid hormones — your thyroid literally can't make T4 or T3 without it. Iodine deficiency has been increasing due to dietary changes and is a reversible cause of hypothyroidism.