Hypothyroidism Prognosis: What to Expect

Generally, the outlook for hypothyroidism is good with proper medical treatment, particularly if it is started early. Most people begin to see a resolution of their symptoms within two weeks of starting medication to treat the condition. However, medication must be continued throughout life.

Hypothyroidism may be due to an autoimmune condition (in which your immune system mistakenly attacks your tissues), such as Hashimoto's thyroiditis, or other processes affecting your thyroid gland that are not autoimmune-related.

Healthcare provider examines person with hypothyroidism

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Thyroid hormone, which is low in hypothyroidism, is integral in the processes of temperature regulation and metabolism in the body. Therefore, a deficiency may impact your ability to stay warm or maintain energy.

As a result, feeling cold or fatigued is a common non-specific symptom that may appear early on before diagnosis. Other common symptoms you might experience include constipation, slight weight gain, and muscle cramps or weakness.

This article will discuss the prognosis for hypothyroidism, how it affects life expectancy, possible complications, and treatment.

Hypothyroidism Prognosis

There is no cure for hypothyroidism. Treatment requires lifelong medication and lifestyle modifications. The prognosis for hypothyroidism is generally good when medication is started early. However, your proper dosage may take some time to figure out, and the dosage may need to be adjusted over time. 

If untreated, hypothyroidism carries a high morbidity (illness) and mortality rate. Untreated hypothyroidism carries an increased risk of medical complications such as intellectual disability, depression, and myxedema coma (coma with low body temperature). Hypothyroidism may induce or exacerbate cardiovascular problems. 

Does Hypothyroidism Affect Life Expectancy?

With proper treatment, a person with hypothyroidism usually has a normal life expectancy, with little or no decrease in quality of life. Hypothyroidism generally carries a greater life expectancy than hyperthyroidism (overactive thyroid).

One study found a 3.5-year difference in life expectancy between those with low-normal thyroid function and high-normal thyroid function in those without cardiovascular disease. However, this data has limitations, such as the lack of racial diversity in the study’s research participants.

Complications of Hypothyroidism

Complications of hypothyroidism usually develop as a result of a lack of treatment. Myxedema coma is the most severe complication of hypothyroidism. It is a life-threatening condition from untreated, undertreated, or undiagnosed hypothyroidism that can lead to coma and organ failure. 

 Other complications include:

  • Goiter (enlargement of the thyroid gland)
  • Peripheral neuropathy (nerve damage)
  • Carpal tunnel syndrome (numbness and tingling in the hands caused by nerve compression)
  • Anemia (reduced red blood cell production in the bone marrow)
  • Muscle disease (myopathy)
  • Infertility
  • Dementia
  • Heart problems
  • Depression

Hypothyroidism Treatment

Hypothyroidism occurs when your thyroid gland doesn’t make enough of the thyroid hormones, triiodothyronine (T3) and thyroxine (T4). Treatment requires that you replace the thyroid hormone you are missing.

T4 makes up the majority of the thyroid hormone in your blood—about 95%. Therefore the most common medical treatment is levothyroxine sodium (brand names include Synthroid, Levoxyl, and Levothroid)—a synthetic version of T4.

If you are low in T3, your healthcare provider may prescribe liothyronine, a synthetic version of T3. Liotrix—a synthetic combination of T4 and T3—is prescribed to those with low levels of both T3 and T4 thyroid hormones.

There is no standard dosage of thyroid hormone. Your healthcare provider will determine the best dosage for you based on the following factors:

  • The physical state of your thyroid gland
  • Thyroid-stimulating hormone (TSH) levels
  • Your diet: Some foods, such as soy-based foods, cruciferous vegetables (such as broccoli, kale, cabbage, and Brussels sprouts), processed or sugary foods, and foods high in gluten (like bread and pasta) may interfere with your body’s ability to absorb thyroid hormone and should therefore be eaten with caution, or avoided altogether in more severe cases of hypothyroidism. 
  • Medications: Oral contraceptives, statins (used to improve cholesterol and reduce cardiovascular risks), and certain anti-seizure medications may interact with your thyroid medications.

What to Expect

People rarely experience hypothyroidism in the same way. One person may have little to no symptoms, while another may experience fatigue, weight gain, intolerance to cold, a puffy face, or thinning hair, prompting them to see a healthcare provider.

After you are diagnosed, your healthcare provider will prescribe thyroid replacement therapy (TRT) and help determine the best dose for you, given your overall health profile.

Levothyroxine—the most commonly prescribed form of TRT—comes in tablets of varying dosages that are taken by mouth. It is important to take the exact amount prescribed. Taking too much may result in symptoms of hyperthyroidism. 

Common side effects of thyroid replacement therapy include:

  • Headache
  • Changes in weight
  • Heat sensitivity
  • Changes in appetite
  • Changes in menstruation
  • Vomiting
  • Diarrhea
  • Hair loss
  • Joint pain
  • Leg cramps
  • Skin rash (may be a sign of an allergic reaction)

If you have a history of heart attack, diabetes, or high blood pressure, check with your healthcare provider to see if TRT is suitable for you. 


The prognosis for hypothyroidism is generally good when medication is started early. However, untreated hypothyroidism carries high risk of medical complications, including coma and death. Hypothyroidism can be treated by replacing thyroid hormone via oral medication.

A Word From Verywell

Hypothyroidism is a highly treatable health condition that usually carries a promising outlook with proper treatment. Finding the correct dose of medication for you may take some time, but once you do, you can expect to start feeling better within a couple of weeks. If you do not, seek immediate medical attention from your healthcare provider.

Frequently Asked Questions

  • Is hypothyroidism permanently curable?

    There is no cure for hypothyroidism, and treatment requires lifelong medication and lifestyle modifications.

  • What are early warning signs of thyroid problems?

    The earliest signs of a thyroid problem may be fatigue, weight gain despite no change in your eating patterns, and feeling sluggish. 

  • When is hypothyroidism life-threatening?

    Hypothyroidism is generally non-life threatening with treatment. However, without treatment, myxedema coma (a serious and life-threatening complication of chronic hypothyroidism characterized by severely low thyroid hormone levels in the blood) can result in coma, organ failure, and death.

  • What happens if you don't treat hypothyroidism?

    Untreated hypothyroidism leads to the progression of the disease and increases the risk of severe medical complications like heart disease, dementia, peripheral nerve damage, infertility, and myxedema coma. 

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Gesing A. The thyroid gland and the process of aging. Thyroid Res. 2015;8(Suppl 1):A8. doi:10.1186/1756-6614-8-S1-A8

  2. Bano A, Dhana K, Chaker L, et al. Association of thyroid function with life expectancy with and without cardiovascular disease: the Rotterdam Study. JAMA Intern Med. 2017;177(11):1650. doi:10.1001/jamainternmed.2017.4836

  3. John Hopkins Lupus Center. Thyroid medications

  4. MedlinePlus. Levothyroxine.

  5. Dortas SD Junior, De Araujo FM, Souza CR, et al. Drug rash induced by levothyroxine and oral desensitization. World Allergy Organ J. 2015;8(Suppl 1):A21. doi:10.1186/1939-4551-8-S1-A21

By Shamard Charles, MD, MPH
Shamard Charles, MD, MPH is a public health physician and journalist. He has held positions with major news networks like NBC reporting on health policy, public health initiatives, diversity in medicine, and new developments in health care research and medical treatments.