If you have been feeling fatigued, dealing with brain fog, or gaining weight, you may need a TSH blood test to check your thyroid function. A TSH test is the blood test that is ordered to evaluate how well your thyroid works.

There are several different thyroid tests, but the most common and the first test done is the thyroid stimulating hormone (TSH) test and possibly the thyroxine (T4) test. The TSH test measures how much thyroid-stimulating hormone (TSH) is in your blood.
TSH is produced in the pituitary gland and communicates to the thyroid gland to produce thyroxine (T4). The T4 test measures the amount of thyroxine in your blood. Thyroxine is the primary hormone produced by the thyroid gland.
The thyroid gland is one of the endocrine system’s glands; this network of glands produces hormones that act like messengers regulating all the functions in your body. High or low thyroid levels can disrupt this message and throw the whole system out of whack.
The TSH Test
The TSH test is used to evaluate thyroid function and to diagnose thyroid disorders, such as Hypothyroidism (underactive thyroid) and Hyperthyroidism (overactive thyroid).
How Are TSH levels monitored?
TSH levels are typically monitored through a blood test. If TSH levels are abnormal, further testing may be needed to determine the cause.
When having a TSH blood test, you should wait until after the blood draw to take your thyroid medications for the day if you are taking them. This timing is vital for accurate testing since your hormones level off 13 hours after taking them.

Interpreting Thyroid Test Results
The laboratory will compare your thyroid test results to a reference range. The reference range is based on values considered normal for a healthy person. Then, your doctor will diagnose your condition using the test results, symptoms, and other factors.
What are normal TSH levels?
Normal TSH levels vary depending on the individual’s age and stage of development. In adults, the normal range is generally considered to be 0.4-4.0 mIU/L.
However, the normal range may vary slightly depending on the laboratory that performs the test. Also, remember that those ranges differ from one doctor to another. For example, one doctor will start treatment when TSH levels are at 5.0, whereas another will only consider starting treatment once those levels have reached 8.0 or higher.
Holistic and functional medicine doctors usually go by a much narrower acceptable range, with the high end being 2.0 or 2.5, so usually, those patients have better symptom control.
What are high TSH levels?
High TSH levels (>4.0 mIU/L) may indicate hypothyroidism, associated with symptoms such as fatigue, weight gain, and depression.
The thyroid hormone controls your metabolism and regulates every function of the body. Your body’s functions slow down if you don’t have enough thyroid hormone.
In addition to the symptoms named above, there are several common low thyroid symptoms:
- Increased sensitivity to cold
- Constipation
- Dry skin
- Weight gain
- Puffy face
- Hoarseness
- Muscle weakness
- Elevated blood cholesterol level
- Muscle aches
- Pain, stiffness, or swelling in your joints
What are low TSH levels?
Low TSH levels (<0.4 mIU/L) may indicate hyperthyroidism associated with anxiety, weight loss, and palpitations.
Common Hyperthyroidism Symptoms
Hyperthyroidism many times mimics other health problems making diagnosis difficult. Common symptoms include:
- Losing weight without trying
- Fast heartbeat, a condition called tachycardia
- Menstrual cycle changes
- Arrhythmia, also known as irregular heartbeat
- Anxiety, irritability, or nervousness
- Tremor, usually of the hands
- Heart palpitations or heart pounding
- Increased hunger
- Sweating
- Heat sensitivity
- Sleep problems
- Goiter or enlarged thyroid gland
- Brittle, fine hair
- Frequent bowel movements
- Thinning skin
- Fatigue
- Muscle weakness
- Warm, moist skin
What can cause high or low TSH levels?
There are many possible causes of high or low TSH levels. Some common causes include autoimmune diseases (such as Hashimoto’s Thyroiditis or Graves’ disease), certain medications (such as lithium or corticosteroids), and pregnancy.
Factors That Can Affect Thyroid Test Results
Certain medications, medical conditions, and pregnancy can affect thyroid test results. If you are taking any medications, have any medical conditions, or are pregnant, be sure to let your doctor know before having a thyroid test.
Biotin– Biotin can falsely give high T4 and T3 levels and low levels of TSH on lab results. As a result, Biotin supplements can skew the results to show hyperthyroidism. Therefore, it’s recommended by The American Thyroid Association that patients stop taking biotin for at least two days before a TSH test.
This pause is requested due to case reports of people taking biotin and having low TSH, high T4, high T3, and elevated TSH-receptor antibodies showing up on lab results.
Supplements containing estrogenic compounds- Supplements with estrogenic additives, such as soy, can result in falsely elevated TSH readings. Soy is a common food sensitivity for those with Hashimoto’s disease.

Medications that interfere with thyroid test results
Some medicines available by prescription or over the counter can affect thyroid function, causing either hypo or hyperthyroidism. In addition, some drugs and foods contain iodine, so patients with thyroid disease who still have their thyroids should exercise caution if using those medications.
Over-the-counter cough and cold medicines often have iodine or other stimulants that can raise blood pressure and increase heart rate.
Supplements containing kelp or seaweed may contain enough iodine to trigger thyroid disease in susceptible individuals.
In addition, commonly used supplements and medications, including iron, calcium, estrogen, statins, and proton pump inhibitors, may cause issues with the absorption of thyroid hormones and binding with plasma proteins. As a result, some patients require an adjustment of their thyroid hormones.
Medications Linked to Hypothyroidism
- Amiodarone
- Bexarotene
- Lithium
- Sulfonamides
- Interferon
- Anticonvulsants
- Iodine
- Glucocorticoids (steroids)
- Ethionamide
- Proton pump inhibitors
- Sunitinib, including other tyrosine kinase inhibitors
- Angiogenesis inhibitors like lenalidomide
- Oral cholecystographic agents for scanning the gallbladder
- Medications that treat seizure disorders such as epilepsy can also disrupt thyroid function. These medications include: Dilantin-may displace thyroid hormone binding. Valproic acid or carbamazepine- may increase the development of hypothyroidism.
Medications Linked to Hyperthyroidism
- Interferon
- Amiodarone
- Iodine
Also, in the beginning, thyroid symptoms are often vague and non-specific. In addition, symptoms can mimic several other health issues, making diagnosis difficult. These symptoms include mental health issues like depression, anxiety, and mood swings.
Richard Asher, an eminent British endocrinologist, reviewed the relationship between psychosis and hypothyroidism in 1949 and added the terminology “myxedema madness” to the thyroid literature.
Myxedema indicates severe hypothyroidism. So, yes, there is a long history of low thyroid hormones making a person feel like they’re crazy!

Thyroid Testing: Diagnosing Thyroid Disease
Standard thyroid tests include:
- TSH
- Total T3-(triiodothyronone)
- Free T3-(free triiodothyronine)
- Free T3/reverse T3 ratio
- Total T4
- Free T4
Testing for Autoimmune Disease:
Thyroid autoimmune disease is when the body’s immune system attacks the thyroid gland. This attack causes several problems, including an overactive thyroid (hyperthyroidism) or an underactive thyroid (hypothyroidism).
What are the symptoms of thyroid autoimmune disease?
The symptoms of autoimmune thyroid disease can vary depending on whether the thyroid is overactive or underactive.
If the thyroid is overactive, symptoms may include:
-Weight loss
-Anxiety
-Insomnia
-Irritability
-Muscle weakness
-Fatigue
If the thyroid is underactive, symptoms may include:
-Weight gain
-Fatigue
-Depression
-Constipation
-Dry skin
-Hair loss
Additional Diagnostic Tests for Thyroid Autoimmune Disease:
Thyroid autoimmune disease is usually diagnosed based on symptoms, a physical examination, and blood tests to check for levels of thyroid hormones and antibodies.
These are the standard thyroid antibodies tests-
- TPOAb- (thyroid peroxidase antibodies)
- TgAb- (thyroglobulin antibodies)
- TSI- (thyroid-stimulating immunoglobulin antibodies)
Your doctor may also request a thyroid scan to evaluate how well your thyroid is functioning.
What Causes Thyroid Autoimmune Disease?
The exact cause of autoimmune thyroid disease is unknown. However, it’s thought to be caused by a combination of genetic and environmental factors.
Many holistic and functional medicine doctors believe that the rise in autoimmune diseases is linked to three ongoing factors: stress, poor diet, and environmental toxins.
I have written a post that shares the 17 toxins that are extremely harmful to our thyroid function. You can read it here: https://knowyourthyroid.com/improving-your-thyroid-gland-function-17-toxins-to-avoid/
Here are the issues these tests may reveal.
THE FOUR BASIC TYPES OF THYROID DISEASE:
1. Hashimoto’s disease: Hashimoto’s disease is an autoimmune disorder that destroys the thyroid gland. This damage leads to decreased thyroid hormone levels, which can cause various symptoms, including fatigue, weight gain, constipation, and depression. Hashimoto’s disease is the usual cause of hypothyroidism in the United States.
2. Graves’ disease: Graves’ disease is an autoimmune disorder that causes the overproduction of thyroid hormone. Excess thyroid hormone causes symptoms including weight loss, anxiety, irritability, and bulging eyes. Graves’ disease is typically the cause of hyperthyroidism in the United States.
3. Thyroiditis: Thyroiditis is an inflammation of the thyroid gland. This swelling can be caused by various things, including an infection, a goiter, or Graves’ disease. In addition, Thyroiditis can temporarily increase or decrease hormone levels, depending on the type of Thyroiditis.
4. Thyroid cancer: Thyroid cancer can occur in or on the thyroid gland. Thyroid cancer is a common endocrine cancer, with the most common thyroid cancer being a lump in the neck. Other symptoms can include hoarseness, difficulty swallowing, and shortness of breath.
Treating Thyroid Disease
Treatment for autoimmune thyroid disease depends on whether the thyroid is overactive or underactive. If the thyroid is overactive, treatment may involve taking immunosuppressive drugs to reduce thyroid hormone levels. RadioActive Iodine therapy or surgery may also be an option.
If the thyroid is underactive, treatment may include taking thyroid hormone replacement therapy.
If the cause is a medication, the offending medication may be discontinued or the dose adjusted.

Hormone Replacement Choices:
Levothyroxine/T4-
The standard of care treatment for low thyroid levels is Levothyroxine.
Synthroid-
The brand-name version of the synthetic compound T4 (Levothyroxine) is used to treat hypothyroidism.
Tirosint (hypoallergenic, liquid capsules)-
Tirosint, the brand-name, liquid form of Levothyroxine, contains no dyes, gluten, alcohol, lactose, or sugar. It is created for those who have allergies to dyes or fillers commonly used in levothyroxine tablets.
Liothyronine/T3-
T3 is the usable form of thyroid hormone. Patients who struggle to convert T4 to T3 find adding T3 helps ease many symptoms.
Cytomel-
The brand name for Liothyronine.
Compounded Hormones-
These replacement hormones are custom-made to the patient’s specific needs. However, they are not usually covered by insurance.
Natural Desiccated Thyroid (NDT)-
Armour Thyroid, Np Thyroid, Nature-Throid, and WP Thyroid are common natural thyroid hormones.
These hormones are made using porcine thyroid and are popular with holistic, alternative, integrative, and functional medicine physicians.
Many patients find they have better symptom control with NDT. This result is commonly achieved for patients with RAI or surgically removed thyroid or who have difficulty converting T4 hormones to T3 hormones.
Studies have shown that at least 50% of patients taking NDT, regardless of the cause, have better symptom control.

Doctor Choices
Yes, the doctor you see for your thyroid issues can make all the difference.
Conventional Doctors-
These are the doctors at clinics and hospitals. They only run specific insurance-covered tests and only prescribe CDC-approved medications.
Endocrinologist-
These are the specialists you see if your disease requires more treatment than your primary care physician can provide. Keep in mind these doctors also treat diabetics, so they may have limited knowledge when it comes to thyroid disease.
Ophthalmologist–
These are eye specialists. You may see one if you have Graves’ disease affecting your eyes.
Primary care physician–
Your primary doctor if you have one. Specific insurance plans require you to have a primary care doctor. These are usually general practitioners.
Internist-
These doctors provide care for adults. They are similar to primary care doctors.
Family practice physician–
A combination of internists and pediatricians as they care for adults and children.
Holistic or Functional Medicine Doctors
These doctors take a different approach to healthcare. For example, many doctors in the following categories focus on healing the body and clearing toxins disrupting your hormone receptors and messengers.
Naturopathic physician-
These doctors use natural medicine along with conventional diagnoses and treatments. They address the causes, work on prevention, and teach healthy living.
Functional medicine physician–
These doctors focus on getting your body to work together; the endocrine, immune, and digestive systems.
Paleo physician–
These doctors follow our ancestor’s diet. It consists of whole meat, fish, eggs, vegetables, fruits, nuts, and seeds—no processed food. Nutrition is the main focus for healing.
Holistic medicine physician- These doctors treat the person’s physical, mental, spiritual, and emotional needs. In addition, they focus on improved nutrition and avoiding chemicals that harm the body.
As you can see, there are several choices for finding a healthcare provider to meet your needs. First, you want to find a doctor who practices healthcare the way you want to live.
That being said, I know many who have thyroid disease have problems finding a healthcare provider who understands the symptoms and how to treat them.
According to Mary Shomon, a thyroid patient advocate, many conventional doctors view thyroid disease as an “easy to test, easy to treat, take a pill, and you’re better” condition. However, this attitude has many who continue to suffer from symptoms seeking alternative medicine options.
ADDITIONAL FACTORS TO MANAGE ONGOING SYMPTOMS

Manage Stress
Stress is listed as one of three main contributors, along with diet and environmental toxins, to the rise in thyroid autoimmune diseases. So take time to relax, walk, read, and do whatever you can to lessen the daily stress we all are under.
Optimize your hormone levels
Work with your provider to optimize your TSH, free T4, and free T3 levels, and not just in the normal range. They need to be optimal for you so most, if not all, of your symptoms, are controlled. Remember that these adjustments to my care plan only happened with my functional medicine doctor.
For example, my TSH is 0.023 IU/ml and is flagged by the laboratory as low. The lab lists their reference ranges as 0.045- 5.330.
My free T4 is 1.07, with a reference range of 0.61-2.00, and my free T3 is 3.1, with a reference range of 2.5-3.9, which is excellent. However, if my TSH levels get higher, it throws off the free T4 and T3 levels, and I have symptoms.
As I mentioned, some patients lose the T4 to T3 conversion capability, leaving them with uncomfortable symptoms. Conventional providers often raise the amount of Levothyroxine you take to ease your symptoms, not realizing the lack of conversion causing the problems.
When I switched from Synthroid to natural thyroid hormones, the constant feeling of being cold disappeared; I was happier and wasn’t so tired. I benefited from adding T3 immediately!
Address Nutritional Deficiencies:
Add supplements to address nutritional deficiencies. Your diet alone won’t be able to meet those needs.
My functional medicine doctor advised me to follow a thyroid-supporting diet like The Hypothyroidism Solution, which shares which foods help your thyroid function better and the ones that hinder its function.
They also provide a cookbook that analyzes each meal’s nutritional analysis and why the ingredients are essential to healing. This program also shares how to detox your home, including yourself, clearing out the toxins that have created the toxic overload your body is struggling with. You also receive information on the vitamins and minerals you should take daily to support your thyroid and help it to heal.
If you are entering perimenopause or menopause, you should check out The Thyroid Factor; this program focuses on balancing all your hormones, including your thyroid. Similar to The Hypothyroidism Solution, The Thyroid Factor addresses the thyroid imbalances and all the hormone imbalances accompanying menopause.
I have also switched from my laundry detergent to Laundry Magnets, reducing the chemicals that contact my skin. This switch has helped lessen the itchiness and dryness of my skin and ease my partner’s congestion from COPD. They are pretty amazing!
Are You Struggling To Find A Provider?
If you have difficulty finding a local healthcare provider who listens and provides proper testing and care, you can order lab tests online.
Several laboratories offer testing online, with many offering consultations with qualified providers who provide thorough treatment plans based on your test results. Thyroid patients who have used online testing have reported excellent results from their treatment plans.
There are many options for finding a healthcare provider who offers the care you need and are comfortable with. For example, I saw several doctors before finding the functional medicine doctor who listened to my symptoms and then set up a treatment plan to control them and heal my body without statins or antidepressants!
Take care,
Corri
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References
https://www.webmd.com/diabetes/endocrine-system-facts
https://en.wikipedia.org/wiki/Richard_Asher
https://www.endocrineweb.com/thyroid-what-are-t3-t4-tsh
https://www.rxlist.com/synthroid-side-effects-drug-center
https://www.goodrx.com/liothyronine/what-is
https://www.medpagetoday.com/endocrinology/thyroid/60471
https://www.canadadrugstore.com/medications-erfa-versus-armour-thyroid-tables/
https://www.mayoclinic.org/diseases-conditions/hyperthyroidism/symptoms-causes/syc-20373659