When healthcare professionals administer thyroid function tests, the value they first look at is TSH or thyroid-stimulating hormone levels. TSH is not a thyroid hormone. Instead, TSH is a hormone produced by the pituitary gland that tells the thyroid, a butterfly-shaped gland in the neck, to secrete thyroid hormones called T3 (triiodothyronine) and T4 (thyroxine). When TSH levels are persistently high, that usually means something is wrong with the thyroid gland. It’s not producing enough thyroid hormone, so the hormone system releases more TSH to increase thyroid hormone production. Healthcare providers call this primary hypothyroidism or underactive thyroid. Thyroid hormones are critical to human life. They affect the entire body: energy use, growth, and body temperature. Without enough thyroid hormones, the body slows down. People feel tired, lethargic, and sensitive to the cold. They gain weight. Their skin dries out, and their hair thins. That’s what TSH feels like for some people. In others, there may be no symptoms of high TSH levels. In rare cases, high TSH may cause hyperthyroidism with polar opposite symptoms.
High TSH is a common health condition that can affect anyone regardless of age, sex, race, or ethnicity.
Early signs of high TSH include fatigue, weight gain, sensitivity to cold, and mood changes.
Serious symptoms of high TSH, such as confusion, cognitive problems, low body temperature, slow breathing, slow reflexes, slow heart rate, and coma, may require immediate medical attention.
High TSH is caused by autoimmune diseases, iodine deficiency, medication side effects, radiation therapy, radioactive iodine therapy, thyroid surgery, pregnancy, and giving birth. You may be at particular risk for developing high TSH symptoms if you are a woman older than 60 or pregnant. Other risk factors include the presence of thyroid antibodies, family history of an underactive thyroid, autoimmune disorders, Type 1 diabetes, or any history of head or neck irradiation. Some babies are born with thyroid dysfunction, a condition called congenital hypothyroidism.
High TSH usually requires a medical diagnosis.
High TSH may or may not require treatment depending on thyroid hormone levels, symptoms, and risk factors. When treated, high TSH symptoms typically resolve within six weeks.
Treatment of high TSH may include levothyroxine if high TSH is associated with hypothyroidism. Read more about hypothyroidism treatments here.
Untreated high TSH could result in complications like goiter, peripheral nerve damage, infertility, birth defects, severe hypothyroidism, myxedema coma, and an increased risk of heart disease.
Use coupons for high TSH treatments like Synthroid (levothyroxine) to save up to 80%.
The most common early signs of high TSH and hypothyroidism are:
Feeling worn down
A sense of being slower than usual
Low energy
Getting cold more easily
Mood changes, especially depression
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High TSH is most commonly associated with underactive thyroid. When thyroid hormones are too low, symptoms affect every part of the body. The most common and recognizable symptoms of high TSH and hypothyroidism are:
Fatigue
Lethargy
Cold sensitivity
Mood changes
Weight gain
Dry skin
Hoarse voice
Less common symptoms include:
Brain fog
Memory problems
Difficulty concentrating or focusing
Depression
Joint pains
Muscle aches and cramps
Weakness
Swelling (fluid retention)
Puffy face
Dry hair
Thinning hair or hair loss
Heavy or prolonged menstrual bleeding
RELATED: Symptoms of thyroid problems: what are the early signs of thyroid issues?
High TSH usually corresponds to hypothyroidism, a medical condition in which the thyroid gland does not produce enough thyroid hormone. Low TSH is usually associated with hyperthyroidism, a thyroid disease involving the overproduction of thyroid hormones. Both thyroid conditions are usually caused by autoimmune disorders. The most common cause of high TSH is an autoimmune disorder called Hashimoto’s disease. The most common cause of low TSH is Grave’s disease. Both involve the immune system attacking healthy tissues in the thyroid, but the effects are exactly the opposite. An underactive thyroid slows down the body and makes people tired, depressed, gain weight, and feel low energy. An overactive thyroid speeds up the body. People feel restless, anxious, energetic, and they usually lose weight.
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RELATED: Hypothyroidism vs. hyperthyroidism: compare causes, symptoms, treatments, & more
If you have symptoms that could be thyroid disease, see a doctor. The only way to definitively diagnose thyroid dysfunction is through thyroid function tests. These are blood tests that measure levels of TSH and thyroid hormones.
A medical history and physical exam are also important in providing clues about a possible cause. The clinician will ask about the symptoms, medications, and any family history of thyroid problems. The clinician may ask about other conditions that are often associated with underactive thyroid, such as high cholesterol.
However, blood tests are the most helpful in diagnosing thyroid disorders. A TSH level is usually the first blood test done. If that is high, then thyroid hormone levels will be tested. The lab tests may also look for anti-thyroid antibodies. The most common cause of hypothyroidism is an autoimmune disorder called Hashimoto’s thyroiditis. The body’s immune system mistakenly attacks healthy thyroid tissues. The blood test will show this by the presence of antibodies against the thyroid.
Many people with TSH levels that are slightly high have normal thyroid hormone levels, a medical condition called subclinical hypothyroidism. Healthcare providers often don’t treat subclinical hypothyroidism but check thyroid function tests again later to see if anything has changed.
RELATED: What causes thyroid symptoms? Related conditions and treatments
When high TSH is associated with low thyroid hormone levels, complications may include:
Thyroid enlargement (goiter)
Peripheral nerve damage
Infertility
Pregnancy problems and birth defects
Increased risk of heart disease
Developmental disabilities (in children)
Myxedema coma, a life-threatening medical crisis with a high mortality rate
Most people with high TSH symptoms will be treated by a primary care physician. In complex cases, a specialist in the body’s endocrine system (hormones) called an endocrinologist may be in charge of treatment.
In people with high TSH levels and normal T4 levels, the standard treatment is to repeat blood tests again in 12 months or so. However, if TSH is very high, thyroid hormone levels are low, or there is a risk of cardiovascular problems or other complications, a healthcare professional will probably start treatment.
The standard treatment for hypothyroidism is thyroid hormone replacement therapy using oral levothyroxine. Taken as a tablet or oral solution, levothyroxine is a human-made version of the thyroid hormone thyroxine (T4). There is no standard dose, so it may take a few weeks before the right dosage is established and symptoms of high TSH resolve. The doctor will administer levothyroxine intravenously for people who cannot take a tablet.
RELATED: 5 things that can mess with your thyroid medication
Some people with high TSH have subclinical hypothyroidism. Although TSH levels are high, thyroid hormone levels are normal. There may be no symptoms, so healthcare professionals may not treat the problem unless the person has very high TSH levels, very high anti-thyroid hormones, or is at risk for cardiovascular problems. Otherwise, healthcare professionals are worried that giving thyroid hormones to people with normal T4 levels might cause other problems, such as osteoporosis.
How many people live with untreated high TSH? About 0.3% of the population has overt hypothyroidism: high TSH, low thyroid hormone, and symptoms of hypothyroidism. About 3.7% of the population has subclinical hypothyroidism: high TSH and normal thyroid hormone levels. Some are treated, some aren’t. That means living with untreated high TSH is pretty common. If that happens, here are some tips for managing high TSH:
First, don’t worry. Most people with subclinical hypothyroidism eventually recover normal TSH levels.
Don’t miss any follow-up visits with healthcare providers or the next blood test scheduled.
Consider keeping a log of any symptoms you might feel over the next few months, particularly symptoms that don’t go away. Share these symptoms with your healthcare team.
Inform the doctor about any changes to your health or the drugs you’re taking.
Symptoms of high TSH are a sign of a serious medical condition called hypothyroidism. If this thyroid dysfunction is allowed to continue, it can cause serious illness or death. The good news is that high TSH and hypothyroidism are treatable. Diagnosis is relatively simple; treatment consists of taking a single pill daily. However, high TSH is not diagnosable outside of a blood test. Only a doctor or other healthcare professionals can order that blood test and start the appropriate treatment.
The relationship between stress and TSH is more complex than it seems. According to research on rats, stress causes the pituitary gland to reduce TSH output. But thyroid hormone levels may also be decreased. However, a study in humans showed that high levels of cortisol, the “stress hormone”, increased levels of TSH but did not affect thyroid hormone levels. Researchers are uncertain if this is something to worry about. Nevertheless, it is always better for health and wellness to manage and reduce stress regardless of your medical conditions.
The standard treatment for high TSH and low thyroid hormone is oral levothyroxine, a synthetic version of the T4 thyroid hormone. Once thyroid medication is started, TSH levels will go down within a few weeks. However, it may take about eight weeks and a series of medication adjustments for TSH levels to return to a normal range.
Mood changes and mood swings are common symptoms of hypothyroidism, the condition most closely associated with high TSH. Numerous studies have shown that people with untreated hypothyroidism are more prone to depression and even suicidality, but they may also experience anxiety, worry, nervousness, irritability, or mood swings.
How to understand thyroid panel results, SingleCare
Hypothyroidism: diagnosis and treatment, American Family Physician
What is a TSH test and what do the results mean?, SingleCare
Hypothyroidism treatments and medications, SingleCare
Thyroid hormones: uses, common brands, and safety info, SingleCare
Treatment of hypothyroidism, American Family Physician
Anne Jacobson, MD, MPH, is a board-certified family physician, writer, editor, teacher, and consultant. She is a graduate of University of Wisconsin School of Medicine and Public Health, and trained at West Suburban Family Medicine in Oak Park, Illinois. She later completed a fellowship in community medicine at PCC Community Wellness and a master's in Public Health at the University of Illinois-Chicago. She lives with her family near Chicago.
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