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High thyroid-stimulating hormone (TSH) levels are associated with hypothyroidism, and one of the signs of hypothyroidism is weight gain
High thyroid-stimulating hormone (TSH) levels are associated with hypothyroidism, and one of the signs of hypothyroidism is weight gain.
What is TSH?
TSH is a glycoprotein that controls the production of two main thyroid hormones: thyroxine (T4) and triiodothyronine (T3). TSH is produced by the pituitary gland, which is part of the brain and plays an important role in performing major vital body functions.
T3 and T4 exert their actions by binding to their receptors located on the cells in the thyroid gland, which is a small butterfly-shaped gland located in front of the trachea. Upon stimulation by TSH, the thyroid gland secretes hormones in circulation, and they perform various actions such as regulating the body weight, temperature, and muscle strength.
The main functions of T3 and T4 are controlling and maintaining metabolic rate and heart health, muscle control, brain development, gut movement, and bone health. Moreover, the brain constantly monitors the levels of thyroid hormones in the blood, and if the amount is too low, it releases TSH to increase the level of thyroid hormones in the blood. When T3 and T4 levels are high, the pituitary gland produces less TSH.
The major drive for TSH production is when the body is low on T3 and/or T4:
- High TSH levels indicate low levels of thyroid hormone activity. Inadequate thyroid hormone production leads to hypothyroidism.
- Low TSH levels indicate high levels of thyroid hormone activity, most likely due to too much thyroid hormone production or hyperthyroidism, which is suppressing TSH
What are the signs and symptoms of high TSH or hypothyroidism?
High levels of TSH indicate that thyroid functions are abnormal and thyroid hormones are not being produced enough, a condition called hypothyroidism. This condition slows metabolism and can lead to following signs and symptoms:
- Weight gain
- Fatigue
- Low energy levels
- Mental fog
- Frequently being cold
- Hair loss
- Irregular menstrual cycles and fertility problems
- Muscle pain and cramps
- Slow pulse
- Low blood pressure
What are the signs and symptoms of low TSH or hyperthyroidism?
Hyperthyroidism is associated with low levels of thyroid-stimulating hormone and causes following signs and symptoms:
- Anxiety
- Weight loss
- Tremors in the hands
- Increased heart rate
- Puffiness
- Bulging of the eyes
- Difficulty sleeping
- Increased appetite
- Sweating
- Heat sensitivity
- Irritability
- Diarrhea
- Insomnia
What are the functions of thyroid hormones?
Thyroid hormones affect almost every cell of the body. T3 and T4 function together to regulate a series of vital functions, which include:
- Metabolic rate
- Weight loss or gain
- Heart rate
- Body temperature
- Digestion
- Muscle control
- Respiratory rate
- Bone health
- Brain development
- Cellular production of energy
- Menstrual cycle
- Growth and development in children
Which conditions cause abnormal TSH levels?
Conditions that can lead to abnormal levels of thyroid-stimulating hormone include:
- Post-pregnancy hypothyroidism
- Pernicious anemia
- Type I diabetes mellitus
- Primary adrenal insufficiency (Addison's disease)
- Turner syndrome
- Autoimmune disease that affects the thyroid gland
- Some cases of lupus
- Rheumatoid arthritis
- Sjogren’s syndrome
- Aging
- Radiation treatments for cancer
- Thyroidectomy (removal or separation of all or part of the thyroid gland)
- Non-functioning thyroid gland at birth
- Iodine deficiency
- Taking medications high in iodine
