Table of ContentsView AllTable of ContentsFunctionsCauses of Abnormal LevelsAssociated ConditionsTSH Test

Table of ContentsView All

View All

Table of Contents

Functions

Causes of Abnormal Levels

Associated Conditions

TSH Test

Thyroid-stimulating hormone (TSH) is a hormone that prompts yourthyroid glandto produce the thyroid hormonestriiodothyronine (T3)andthyroxine (T4). Thehypothalamus, located in the brain, constantly monitors your blood for levels of thyroid hormones, and if it detects too little, it triggers thepituitary gland, also located in the brain, to release TSH.

This system of communication keeps your thyroid hormone levels within the optimal range. If you have enough or too much T3 or T4, the pituitary gland slows down the production of TSH, which signals your thyroid to produce less T3 and T4.

Lars Neumann / iStock / Getty Images

Thyroid stimulating hormone is released from the pituitary gland

Thyroid Hormone Functions

T3 and T4 work together, along with other hormones in your body to regulate many vital functions, including:

Thyroid hormones literally have an impact on every cell in your body, so when their levels are not within normal ranges, that can have a major impact on your health.

How Your Thyroid Works

Causes of Abnormal TSH Levels

Several different things can cause your TSH levels to be abnormal.

Some conditions that can affect your thyroid gland include:

Other factors associated with TSH abnormalities include:

Iodineis essential for the proper production and function of the thyroid hormones. Your body cannot produce iodine, though, so you have to get it through your diet or nutritional supplements. Some natural sources of iodine are:Fish and other seafoodDairy productsGrainsIodized salt

Iodineis essential for the proper production and function of the thyroid hormones. Your body cannot produce iodine, though, so you have to get it through your diet or nutritional supplements. Some natural sources of iodine are:

High TSH levels are associated with low levels of thyroid hormones, and low TSH levels are associated with high levels of thyroid hormones.

When levels are slightly abnormal and without symptoms, it’s classified as a subclinical thyroid disorder.Some people diagnosed with a subclinical thyroid disorder eventually go on to develop full-blown thyroid disease.

A condition called thyroiditis is a type of inflammation of the thyroid gland that interferes with hormone production. It can be associated with either high levels or low levels of TSH.

Hyperthyroidism and Graves' disease are associated with low levels of TSH and high thyroid function.Hypothyroidism and Hashimoto’s disease are associated with high levels of TSH and low thyroid function.

Hyperthyroidism

Also called overactive thyroid, this condition accelerates your metabolism.

Symptoms include:

Treating Hyperthyroidism

Graves’ Disease

In this autoimmune condition, the immune system’s attack on the thyroid gland causes it to malfunction and produce excess hormones. The symptoms are generally the same as those of hyperthyroidism.

In addition, Graves’ is often associated with:

Graves’ ophthalmopathy develops due to the autoimmune process. It can give your eyes a bulging appearance because it causes increased pressure around the eyes. It can also cause eye sensitivity and decreased vision.

What Is Graves' Disease?

Hypothyroidism

Also called underactive thyroid, this condition slows the metabolism and can lead to:

Treating Hypothyroidism

Hashimoto’s Disease

Sometimes calledHashimoto’s thyroiditis, this is an autoimmune disease in which the immune system attacks healthy thyroid tissues. Symptoms are similar to those of hypothyroidism but may be more severe.

Some women experience a drop in thyroid function after giving birth, which is calledpostpartum thyroiditis. This is typically a temporary condition, with the function returning to normal over time.

TSH Testing Interpretations

TSH is an important marker for determining whether someone has thyroid disease.

TSH Test Result InterpretationsmU/LDIAGNOSIS4.7-10Subclinical hypothyroidismOver 10Hypothyroidism0.1-0.5Subclinical hyperthyroidismBelow 0.1HyperthyroidismSometimes, a healthcare provider will order tests for TSH, free T3, and free T4 together, possibly with other tests to get a more complete picture of how well your thyroid gland is functioning.Understanding Thyroid Test ResultsA Word From VerywellIf you have symptoms that may be suggestive of a thyroid disorder, it’s important for you to get an appointment with your healthcare provider. These disorders are common and treatable, so there’s no reason for you to continue dealing with unpleasant—and potentially dangerous—symptoms.Can You Have Hypothyroidism With Normal TSH Levels?

Sometimes, a healthcare provider will order tests for TSH, free T3, and free T4 together, possibly with other tests to get a more complete picture of how well your thyroid gland is functioning.

Understanding Thyroid Test Results

A Word From Verywell

If you have symptoms that may be suggestive of a thyroid disorder, it’s important for you to get an appointment with your healthcare provider. These disorders are common and treatable, so there’s no reason for you to continue dealing with unpleasant—and potentially dangerous—symptoms.

Can You Have Hypothyroidism With Normal TSH Levels?

7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.University of Michigan: Michigan Medicine.Thyroid hormone production and function.Cleveland Clinic.Thyroid disease.National Institutes of Health, Office of Dietary Supplements.Iodine: Fact sheet for consumers.Sheehan MT.Biochemical testing of the thyroid: TSH is the best and, oftentimes, only test needed - A review for primary care.Clin Med Res. 2016;14(2):83-92. doi:10.3121/cmr.2016.1309National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Hyperthyroidism.Bahn RS.Graves' ophthalmopathy.N Engl J Med. 2010;362(8):726–738. doi:10.1056/NEJMra0905750National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Hypothyroidism. Updated September 2, 2020.Additional ReadingBahn RA, Burch HB, Cooper DS, Garber JR, Greenlee MC, et al.Hyperthyroidism management guidelines.Endocr Pract. (No.3)457.Garber JR, Cobin RH, Gharib H, Hennessey JV, Klein I, et al.ATA/AACE guidelines for hypothyroidism in adults.Endocr Pract. (No.6)989.National Center for Biotechnology Information, U.S. National Library of Medicine.How does the thyroid gland work?

7 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.University of Michigan: Michigan Medicine.Thyroid hormone production and function.Cleveland Clinic.Thyroid disease.National Institutes of Health, Office of Dietary Supplements.Iodine: Fact sheet for consumers.Sheehan MT.Biochemical testing of the thyroid: TSH is the best and, oftentimes, only test needed - A review for primary care.Clin Med Res. 2016;14(2):83-92. doi:10.3121/cmr.2016.1309National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Hyperthyroidism.Bahn RS.Graves' ophthalmopathy.N Engl J Med. 2010;362(8):726–738. doi:10.1056/NEJMra0905750National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Hypothyroidism. Updated September 2, 2020.Additional ReadingBahn RA, Burch HB, Cooper DS, Garber JR, Greenlee MC, et al.Hyperthyroidism management guidelines.Endocr Pract. (No.3)457.Garber JR, Cobin RH, Gharib H, Hennessey JV, Klein I, et al.ATA/AACE guidelines for hypothyroidism in adults.Endocr Pract. (No.6)989.National Center for Biotechnology Information, U.S. National Library of Medicine.How does the thyroid gland work?

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

University of Michigan: Michigan Medicine.Thyroid hormone production and function.Cleveland Clinic.Thyroid disease.National Institutes of Health, Office of Dietary Supplements.Iodine: Fact sheet for consumers.Sheehan MT.Biochemical testing of the thyroid: TSH is the best and, oftentimes, only test needed - A review for primary care.Clin Med Res. 2016;14(2):83-92. doi:10.3121/cmr.2016.1309National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Hyperthyroidism.Bahn RS.Graves' ophthalmopathy.N Engl J Med. 2010;362(8):726–738. doi:10.1056/NEJMra0905750National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Hypothyroidism. Updated September 2, 2020.

University of Michigan: Michigan Medicine.Thyroid hormone production and function.

Cleveland Clinic.Thyroid disease.

National Institutes of Health, Office of Dietary Supplements.Iodine: Fact sheet for consumers.

Sheehan MT.Biochemical testing of the thyroid: TSH is the best and, oftentimes, only test needed - A review for primary care.Clin Med Res. 2016;14(2):83-92. doi:10.3121/cmr.2016.1309

National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Hyperthyroidism.

Bahn RS.Graves' ophthalmopathy.N Engl J Med. 2010;362(8):726–738. doi:10.1056/NEJMra0905750

National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Hypothyroidism. Updated September 2, 2020.

Bahn RA, Burch HB, Cooper DS, Garber JR, Greenlee MC, et al.Hyperthyroidism management guidelines.Endocr Pract. (No.3)457.Garber JR, Cobin RH, Gharib H, Hennessey JV, Klein I, et al.ATA/AACE guidelines for hypothyroidism in adults.Endocr Pract. (No.6)989.National Center for Biotechnology Information, U.S. National Library of Medicine.How does the thyroid gland work?

Bahn RA, Burch HB, Cooper DS, Garber JR, Greenlee MC, et al.Hyperthyroidism management guidelines.Endocr Pract. (No.3)457.

Garber JR, Cobin RH, Gharib H, Hennessey JV, Klein I, et al.ATA/AACE guidelines for hypothyroidism in adults.Endocr Pract. (No.6)989.

National Center for Biotechnology Information, U.S. National Library of Medicine.How does the thyroid gland work?

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