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Understanding Thyroid Stimulating Hormone Ranges or TSH. Dr Hagmeyer Video Series

A TSH test measures the amount of thyroid stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland. It prompts the thyroid gland to make and release thyroid hormones into the blood. Blood tests for thyroid function are an important part of the process for diagnosing thyroid disease. Reference range is a critical component, and the validity of the entire TSH test as diagnostic tool depends on it. TSH reference range is what determines — for the vast majority of physicians, whether or not thyroid disease is diagnosed and treated. But what you might not know is that these ranges are not Optimal Thyroid ranges and there is much more to the thyroid story than just looking at TSH and Free T4.

For many women and men who suffer with thyroid symptoms this can be frustrating and is one of the reasons I did this video. In this video, Dr. Hagmeyer explains why proper testing of the Thyroid requires more than just TSH and T4.  

High thyroid-stimulating hormone (TSH) levels based on a TSH test may mean you have hypothyroidism (underactive thyroid), while low TSH levels suggest hyperthyroidism (overactive thyroid). TSH values are described as follows:1

  • Normal: Between 0.4 and 4.0 mU/L
  • High: Over 4.5 mU/L
  • Low: Under 0.4 mu/L

But, there are exceptions to these interpretations as well as variations as to what a “normal” TSH level is. This is because TSH levels can vary by age, male and female sex, and other factors. In the end, the results need to be interpreted alongside other thyroid function tests to make the correct diagnosis.

TSH Testing- I’m So Confused

TSH levels may seem counterintuitive. Why does a high TSH mean you have an underactive thyroid gland? And why do low levels mean it’s overactive?

To answer that, you have to know that TSH marker and thyroid hormones markers are different things. The thyroid hormones are:

  • T3 (triiodothyronine)
  • T4 (thyroxine)

While TSH is the signal coming from the pituitary gland that instructs the thyroid how much or how little hormone it needs to make. The confusion comes in when doctors tell patients that based on their bloodwork their thyroid is “normal”. What your doctor is probably saying is that your TSH is normal. This is not the same as running a comprehensive thyroid panel that looks at both TSH and other thyroid markers. If your doctor only tested your TSH, there is not enough information to say whether or not your thyroid is normal or abnormal. I wrote this article that explains “Why the TSH maker can be misleading”

Order a comprehensive Thyroid Panel for your own well being

High TSH

A high TSH often means that a person has a depressed or low level of thyroid hormones, but this needs to be confirmed by testing the actual thyroid hormone levels.

This is by far the most common form of hypothyroidism, and it occurs because the thyroid gland produces an inadequate amount of thyroid hormones. The pituitary gland senses these low levels and increases the production of TSH. An elevated TSH may also occur with normal thyroid function due to the presence of antibodies, proteins made by the immune system.


A low TSH often means that a person has an elevated level of thyroid hormones, but this needs to be confirmed by testing the actual thyroid hormone levels.

What Are the Early Signs of Thyroid Problems? 2

In People Without Known Thyroid Disease

Low TSH is most often associated with hyperthyroidism. This can be due to a number of causes, ranging from autoimmune disease to lumps in the thyroid gland (toxic nodules) to an abnormally enlarged thyroid gland (goiter).It can also occur during a normal pregnancy as thyroid hormones are affected by “the pregnancy hormone” human chorionic gonadotropin (hCG).

Less often, a lack of TSH produced by the pituitary gland (due to dysfunction) can lead to low levels of thyroid hormone in the blood—a condition known as central hypothyroidism. This is an exception to the general rule that hypothyroidism is associated with a high TSH.

Central hypothyroidism is uncommon and usually associated with a deficiency of other pituitary hormones. This deficiency leads to a number of other symptoms as well.

A number of other factors can affect TSH test results, including:

  • The time of day that the test is done: If you are tested after fasting—for example, before you have eaten anything for the day—your TSH levels may be higher than if you had eaten just before your test.2
  • Illness: Acute or chronic illnesses may put stress on your endocrine system, resulting in a skewed test result.
  • Pregnancy: TSH levels may be lower than the normal range during pregnancy, regardless of whether or not you have a thyroid disorder.
  • Medications: Some medications that are used to treat heart disease and cancer may affect results. Nonsteroidal anti-inflammatory medications, or NSAIDs, like Advil (ibuprofen) can as well.
  • Foods or supplements: Items rich in iodine or derived from kelp may interfere with testing.3 The same is true about biotin supplements.4
  • Changes in sleep habits: A lack of quality sleep has been linked with thyroid imbalances.5

What to Look for in a Hashimoto's Doctor 1

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Our Personal Thyroid Recovery Program Customized to the Individual. NO cookie cutter approaches.

The Personal Program Thyroid Recovery Program is a Natural Treatment for Low Thyroid function, Hypothyroidism, Hyper thyroidism and Hashimoto’s problems. Our office utilizes nutritional supplements, Dietary modifications, Hormone and endocrine support formula, bio-identical hormone replacement and lifestyle guidance.

1. Have Questions about becoming a patient. Learn more here

2.  Free 15 minute personalized Phone consult is a great place to start.

3. Interested in having a comprehensive thyroid panel evaluation done for your own well being? You can order Thyroid testing here and then have your bloodwork drawn wherever you live.

4. Have Thyroid symptoms but your doctor says your thyroid is “Normal” take our online Thyroid Quiz to assess your risk

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