An overactive thyroid is also known as hyperthyroidism or thyrotoxicosis.
Free T4 (free thyroxine) is the active form of thyroxine, released from the thyroid gland in the neck. Its role is to control metabolism - the release of energy from all cells of the body. A lack of thyroxine leads to, for example, tiredness and weight gain, whereas an excess will lead to weight loss, rapid heart rate and anxiety. It is generally believed that this level (FT4) is the most reliable indicator of thyroid status - i.e. whether the gland is over-active (hyperthyroidism) or underactive (hypothyroidism).
TSH (thyroid-stimulating hormone) is a hormone manufactured in the pituitary gland (found in the brain). It s role is to stimulate thyroxine production in the thyroid gland (found in the neck).
what causes hyperthyroidism
Having too much of these hormones can cause unpleasant and potentially dangerous problems that may need treatment for symptoms of hyperthyroidism
- Weight loss with increased appetite
- Warm/clammy skin
- Shortness/loss of breath
- Feeling warm and sweating excessively
- Feeling hyperactive
- Rapid heartbeat
- Raised libido
- Irregular bowel movements
- Thin hair
- Fertility problems