Thyroid hormones affect every cell and all the organs of the body. Too much thyroid hormone speeds things up, and too little thyroid hormone slows things down. They:
- Control the rate at which your body burns calories (your metabolism). This affects whether you gain or lose weight.
- Can slow down or speed up your heartbeat.
- Can raise or lower your body temperature.
- Change how quickly food moves through your digestive tract.
- Affect muscle strength.
- Control how quickly your body replaces dying cells.
Thyroid hormones are made by the thyroid gland. The thyroid gland makes and releases two thyroid hormones: thyroxine (T4) and triiodothyronine (T3).
The thyroid gland and the pituitary gland work together. The pituitary gland (located near the base of the brain) makes, stores, and releases thyroid-stimulating hormone (TSH). When TSH is secreted by the pituitary gland, it causes the thyroid gland to release more T3 and T4. A high TSH level means there isn't enough thyroid hormone. A low TSH level means there is too much.
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Current as of: July 7, 2025
Current as of: July 7, 2025