TSH (Thyroid-Stimulating Hormone)
TSH (Thyroid-Stimulating Hormone)
Couldn't load pickup availability
Share
Description
The thyroid gland is a butterfly-shaped organ located around the trachea at the front of the neck, just below the larynx. It produces thyroid hormones, which are essential for regulating the body’s metabolism—essentially, the speed at which our cells function. Thyroid disorders, in the form of either an underactive or overactive thyroid, affect 2-4% of the population and are ten times more common in women. The brain’s hypothalamus helps regulate thyroid function through a feedback mechanism. If there isn’t enough thyroid hormone in the blood, the pituitary gland at the brainstem releases thyroid-stimulating hormone (TSH), prompting the thyroid to produce and release the hormones T4 and T3 into the bloodstream. Any disruption in this feedback loop is likely to cause a thyroid dysfunction.
Blood tests to detect thyroid disorders typically measure levels of TSH along with free T4, and sometimes free T3, in the blood. A TSH test measures the amount of thyroid-stimulating hormone in the blood. There are several reasons to analyze TSH levels, with the primary purpose being to determine if the thyroid is functioning properly. Analyzing free T4 along with TSH provides a clear picture of thyroid function and helps detect potential hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid). In cases where hypo- or hyperthyroidism has been confirmed, a TSH analysis can help determine if the issue originates in the thyroid or the pituitary gland. Additionally, TSH is a sensitive marker to monitor the effectiveness of thyroid hormone replacement therapy (e.g., Levaxin or Euthyrox). Regular TSH tests are often recommended when treating a thyroid condition. If thyroid medication dosage is adjusted, it is advisable to wait 6-8 weeks before retesting TSH levels to accurately assess the medication’s impact, as testing earlier may not reflect its true effect.
High TSH Levels
Elevated TSH levels, combined with low free T4, may indicate an underactive thyroid (hypothyroidism). TSH can also temporarily increase due to physical stress or infections.
Low TSH Levels
Thyroid hormone underproduction is associated with reduced volume in the right hippocampus (1). Low TSH levels, together with high free T4, may indicate an overactive thyroid (hyperthyroidism). Low TSH levels along with low free T4 may indicate pituitary gland dysfunction. TSH levels may also temporarily decrease due to physical stress or infections.
