Thyroid stimulating hormone (TSH) is produced by the pituitary gland in the brain. It tells the thyroid gland to make and release thyroid hormones into the bloodstream. These thyroid hormones, T3 and T4, help control the speed of your metabolism. When the pituitary gland senses that levels of T3 and T4 are low, it releases more TSH to tell the thyroid to produce more hormones.
What is considered a high TSH level?
In most labs, a normal TSH level ranges between 0.4 and 4.0 mIU/L. A TSH above 4.0 mIU/L is generally considered elevated and indicates hypothyroidism or underactive thyroid. The higher the TSH, the more severe the hypothyroidism. Some key TSH levels include:
- 0.4 to 2.0 mIU/L – Normal
- 2.0 to 4.0 mIU/L – Mild hypothyroidism
- 4.0 to 10 mIU/L – Moderate hypothyroidism
- 10+ mIU/L – Severe hypothyroidism
It’s important to understand that TSH levels can fluctuate and should be interpreted based on an individual’s symptoms and other thyroid blood tests like T4. A TSH above 10 mIU/L, however, usually indicates an underactive thyroid.
Symptoms of high TSH levels
Elevated TSH reflects that the body is signaling the thyroid gland to try harder to produce more thyroid hormones. The higher the TSH, the more likely you’ll experience hypothyroidism symptoms. Common symptoms include:
- Fatigue – Feeling exhausted despite getting adequate sleep. Difficulty getting out of bed in the morning.
- Brain fog – Trouble concentrating, focusing, or remembering things. Feeling spaced out.
- Depression – Feeling down, sad, or hopeless persistently.
- Weight gain – Putting on weight unexpectedly despite eating healthy and exercising.
- Muscle aches – Stiff, sore muscles, particularly in the shoulders and hips.
- Joint pain – Swollen, painful joints. Discomfort moving joints.
- Hair loss – Thinning hair or excessive hair shedding.
- Dry skin – Flaky, itchy skin that doesn’t improve with moisturizer.
- Irregular periods – Abnormal menstrual cycles, heavy or painful periods.
- Constipation – Infrequent, hard, dry bowel movements.
- Sensitivity to cold – Always feeling chilly, even in warm environments.
Keep in mind that you may not experience all of these symptoms. The signs can be quite subtle in the beginning stages of hypothyroidism. Symptoms tend to become more pronounced as the TSH level rises.
What causes high TSH?
There are several potential causes of elevated TSH levels:
- Hashimoto’s thyroiditis – An autoimmune disease where the immune system attacks and damages the thyroid gland. This is the #1 cause of hypothyroidism.
- Thyroid cancer treatment – Surgery, radioactive iodine therapy, or radiation treatments for thyroid cancer can cause hypothyroidism.
- Thyroid injury – Physical injury to the thyroid gland from things like radiation or amiodarone medications.
- Pituitary gland tumors – Tumors in the pituitary gland may overproduce TSH.
- Pituitary gland inflammation – Pituitary inflammation prevents normal TSH production.
- Medications – Drugs that affect thyroid function like lithium, interferon alpha, and interleukin-2.
- Iodine deficiency – Lack of sufficient iodine impairs thyroid hormone production.
Hashimoto’s is the most common cause, accounting for 90% of hypothyroidism cases in the United States. Postpartum thyroiditis after pregnancy is also a frequent cause of elevated TSH in women.
Risk factors
You may have an increased likelihood of high TSH levels or hypothyroidism if you:
- Have a family history of thyroid disease
- Have an autoimmune disorder like type 1 diabetes or celiac disease
- Have been treated for hyperthyroidism in the past
- Had thyroid surgery or radiation therapy to the neck or chest area
- Have been pregnant or delivered a baby in the past 6 months
- Are over age 60
- Have been treated for depression
- Have a goiter or thyroid nodules
Women are at higher risk than men, and risk increases with age. Environmental factors like stress and high iodine intake can also impact thyroid function.
Diagnosing high TSH
If you have symptoms of an underactive thyroid, your doctor will likely check a TSH test along with T4 and T3 levels. They may also test for thyroid antibodies to determine if an autoimmune cause like Hashimoto’s is responsible. Imaging tests like an ultrasound can check the structure of your thyroid gland.
TSH is considered the best initial test for suspected hypothyroidism. If it comes back high, your doctor will usually order additional thyroid function tests. These may include:
- Total T4
- Free T4
- Total T3
- Free T3
- Thyroid peroxidase (TPO) antibodies
- Thyroglobulin antibodies
Evaluating all of these thyroid labs together can help confirm a diagnosis of hypothyroidism. Your doctor may also test cholesterol levels, vitamin D, and anemia to assess whether high TSH is affecting other parts of your health.
How is high TSH treated?
The main treatment for elevated TSH is oral medication to replace thyroid hormone. Options include:
- Levothyroxine (Synthroid, Levoxyl) – Synthetic T4 that brings TSH back to normal.
- Liothyronine (Cytomel) – Synthetic T3 that can be added if T4 alone doesn’t relieve symptoms.
- Desiccated thyroid (Armour, Nature-Throid) – Contains both T4 and T3 derived from porcine thyroid glands.
Most doctors prescribe a daily dose of levothyroxine. The dosage is gradually adjusted based on repeat TSH testing until it reaches an optimal level. It may take several months to determine the proper dosage. Treatment is generally lifelong for hypothyroidism.
TSH Treatment Goals
| Patient Group | TSH Goal |
|---|---|
| Healthy, under age 60 | 0.4 – 2.5 mIU/L |
| Over age 60 | 0.4 – 3.0 mIU/L |
| Pregnant | 0.1 – 2.5 mIU/L (first trimester) 0.2 – 3.0 mIU/L (second/third trimesters) |
In addition to medication, managing high TSH may involve diet changes, thyroid-friendly supplements, stress relief, and regular TSH monitoring. Finding and treating any underlying autoimmune disorder is also recommended.
Complications of untreated high TSH
Leaving elevated TSH untreated over the long-term can lead to various complications:
- Goiter – Enlargement of the thyroid gland as it struggles to produce more hormones.
- Heart disease – Increased cholesterol levels and blood pressure from hypothyroidism.
- Mental impairment – Worsening forgetfulness, confusion, and dementia from low thyroid hormones.
- Infertility – Irregular menses and ovulation difficulties making conception harder.
- Birth defects – Untreated hypothyroidism during pregnancy associated with birth defects.
- Myxedema – Life-threatening form of severe hypothyroidism with symptoms like low temperature, slow heart rate, and coma.
That’s why it’s important to consult a doctor if you have any symptoms or risk factors for thyroid problems. Monitoring TSH and treating high levels can prevent serious hypothyroidism complications.
Tips for managing high TSH
If you’ve been diagnosed with elevated TSH, here are some tips that can help you manage it:
- Take thyroid medication consistently every day, preferably first thing in the morning on an empty stomach.
- Wait 30-60 minutes before eating or drinking anything besides water after your medication.
- Get your TSH rechecked 4-8 weeks after starting treatment or changing your dosage.
- Watch for medication interactions that can affect thyroid function.
- Reduce consumption of foods that suppress thyroid function like soy, cruciferous vegetables, and gluten.
- Enjoy thyroid-healthy foods like fish, berries, nuts, and seeds.
- Consider supplements like selenium, zinc, probiotics, and vitamin D.
- Find ways to manage stress through meditation, yoga, massage, or other relaxation practices.
- Get regular moderate exercise for at least 30 minutes per day.
- Maintain a healthy body weight and avoid crash diets that can impact thyroid function.
Diet Tips for High TSH
Making some dietary modifications can help support your thyroid:
| Foods to Enjoy | Foods to Limit |
|---|---|
| Seafood high in omega-3s like salmon, sardines | Soy products like tofu, edamame |
| Nuts and seeds like walnuts, pumpkin seeds | Cruciferous vegetables – broccoli, cauliflower, cabbage |
| Berries like strawberries, blueberries | Refined grains like white bread, pasta |
| Probiotic foods like yogurt, kefir | Added sugars in sweets, sugary drinks |
| Fiber-rich fruits and vegetables | Processed and fried foods |
| Legumes like lentils, chickpeas | Gluten if sensitive |
Living with high TSH
Managing life with elevated TSH levels often requires some lifestyle adjustments, but doesn’t have to take over your life. Here are some tips for living well:
- Find a good endocrinologist experienced in treating thyroid disorders.
- Join a thyroid disease support group to connect with others facing similar challenges.
- Learn as much as you can about thyroid conditions and optimal treatment approaches.
- Tell your family and close friends about your thyroid disorder so they understand.
- Reduce stress and make time for relaxing, rejuvenating activities.
- Listen to your body – rest and slow down when your energy is low.
- Be patient with the process – it can take time to regulate TSH and feel your best.
Although thyroid problems can be burdensome at times, they are very manageable diseases. Taking your medication regularly, maintaining a healthy lifestyle, and working closely with your healthcare team can help you successfully manage high TSH and feel well.
Conclusion
Elevated TSH levels indicate that the thyroid gland is being stimulated to work harder to produce more hormones. This causes symptoms of hypothyroidism including fatigue, weight gain, hair loss, and sensitivity to cold. There are various potential causes, with Hashimoto’s thyroiditis being the most common. High TSH is diagnosed with a simple blood test and then treated with oral thyroid hormone replacement medication. Managing high TSH requires medication, regular monitoring, and a thyroid-friendly lifestyle. Addressing elevated thyrotropin levels prevents complications and allows patients to feel their best.