The thyroid sets how fast your body burns fuel. A feedback loop with the brain keeps it in check. See the normal loop first. Then see what happens when the thyroid does too little or too much.
Normal axis
The thyroid axismetabolism control
TSH
T₃ / T₄
📷 Reference image
A real labeled figure. Compare it with the interactive above.
The Thyroid Axis — OpenStax, CC BY 3.0 (via Wikimedia Commons)