What is a thyroid-stimulating hormone (TSH) test?
Thyroid-stimulating hormone (TSH) test is a laboratory blood test that measures how well the thyroid gland is working. The thyroid gland is a small butterfly-shaped gland near your throat. The hormones made by the thyroid play an important role in regulating your weight, body temperature, muscle strength, and mood.
The pituitary gland in your brain is where TSH comes from. When thyroid levels in your body are low, the pituitary gland makes more TSH to tell your thyroid to produce more hormone. The opposite happens when thyroid levels in the body are high. So measuring the TSH shows how well the thyroid gland is working.
What happens when thyroid stimulation hormone is high?
When TSH is high, it means that your thyroid gland is not making enough thyroid hormone. This is called hypothyroidism. Symptoms of high TSH or hypothyroidism include:
- Depression
- Fatigue
- Slow heart rate
- Puffy face
- Feeling cold
- Hair loss
- Constipation
- Dry skin and hair
- Infertility
- Irregular menses
- Heavy menses
- Joint and muscle pain
What causes TSH levels to rise?
TSH levels rise when the thyroid gland is not making enough thyroxine. This triggers the pituitary gland to increase production of TSH in an attempt to tell the thyroid gland to make more thyroxine.
Conditions that can cause the TSH to rise include:
- Hashimoto’s thyroiditis - an autoimmune inflammation of the thyroid
- Hormonal changes
- Certain medications
- Injury to the thyroid (such as from radiation treatments)
- Partial or complete removal of the thyroid gland
- Pituitary tumors
What is the normal range of TSH in females?
Normal TSH levels in females are 0.5 - 5.0 mIU/L. During menstrual cycles, pregnancy, or menopause, TSH levels might be a little lower than expected because of fluctuating estrogen levels.
What are early warning signs of thyroid problems?
Early warning signs of thyroid problems include:
- Bowel changes - either constipation or diarrhea
- Mood changes - easy to anger/anxious or depressed
- Weight changes
- Skin problems - dry or oily skin
- Sensitivity to temperature changes
- Vision changes - dry eyes, watery eyes, bulging eyes
- Hair thinning or hair loss
- Memory problems
- Lumps or nodules in the thyroid
How is high TSH treated?
High TSH or hypothyroidism is treated with a medication that replaces thyroid hormone. Levothyroxine is the medication that is usually used to replace thyroid hormone. In some cases, your healthcare provider may also prescribe triiodothyronine. The TSH level will be monitored with labs as the medication dose is adjusted. This is how your healthcare provider will know the correct dose for you.
