Why Hypothyroidism Often Goes Undiagnosed:
Many people suffer from symptoms of an underactive thyroid but are not diagnosed with hypothyroidism. Often, individuals visit their doctor with a range of diffuse, low-thyroid symptoms. However, when their thyroid blood test results fall within the normal reference ranges, they are told their thyroid function is fine, and their symptoms are often attributed to other causes, including psychological issues like depression or stress.
The underlying issue is that the normal reference ranges for thyroid blood tests are very broad. This means that even individuals with genuine symptoms of hypothyroidism can easily fall within the “normal” ranges and go undiagnosed.
Dr. Ray Peat, a leading thyroid expert, dedicated his research to helping countless individuals overcome thyroid and hormonal issues. He highlighted the critical need for a more accurate method of assessing thyroid health. Dr. Peat emphasized interpreting thyroid lab results with optimal values rather than relying on broad reference ranges. He also recommended monitoring metabolism at home by tracking pulse rate, temperature, and other signs of low thyroid function.
For a comprehensive guide on testing and understanding thyroid health, my book, Test Your Thyroid Function, explores these concepts in detail, building on Dr. Peat’s approach to effective thyroid assessment.
Thyroid Blood Tests:
Doctors assess thyroid health through blood tests, typically measuring Thyroid-Stimulating Hormone (TSH) along with thyroid hormones T4 and T3. While these tests provide valuable insights, it’s essential to understand their limitations.
the TSH blood test:
The TSH test is usually the first test a doctor orders to evaluate thyroid function. When thyroid function declines, TSH levels rise, indicating hypothyroidism. However, determining the exact TSH threshold for diagnosing hypothyroidism can be challenging. In many countries, TSH levels up to 4 or even 5 are deemed normal. Dr. Ray Peat, however, suggested that low thyroid symptoms often appear when TSH exceeds 2. He recommended keeping TSH below 1, ideally around 0.4, for optimal thyroid health.
Notably, TSH can also be suppressed by stress hormones like cortisol, so individuals under stress may have a deceptively low TSH. Ironically, people with hypothyroidism often overproduce cortisol, putting them at risk of a low TSH reading, even if they have an underactive thyroid. Unfortunately, the impact of stress hormones on TSH is rarely considered by doctors when evaluating thyroid health.
T4 and T3 blood test:
T4 and T3 are the two primary hormones secreted by the human thyroid gland, measurable in the blood. T4 serves as a storage hormone that converts into T3, the active thyroid hormone responsible for increasing cellular metabolic activity. In the bloodstream, the majority of T4 and T3 are protein-bound, with only a small portion existing as “free” hormones. While some doctors measure these “free” levels, Dr. Peat argued that they are not the most reliable indicators of thyroid function. Instead, he emphasized the importance of measuring total T4 and T3 levels, which account for both bound and unbound hormones.
Reverse T3 Blood Test:
The reverse T3 (rT3) test is another valuable measure. Reverse T3, an inactive thyroid hormone, often rises under stress. Dr. Peat highlighted the importance of rT3 testing, particularly when low thyroid symptoms persist despite normal T4 and T3 levels. Despite its significance, doctors are often reluctant to order the rT3 test. For more on rT3 see the blog post Anti-Thyroid Effect of Reverse T3.
How much can thyroid blood test reveal about thyroid function:
Dr. Peat emphasized that thyroid blood tests are most informative when interpreted against optimal, rather than broad, reference ranges. However, T3 blood levels don’t always accurately reflect cellular thyroid function, as factors such as stress, diet, and the influence of other hormones affect T3 activity at the cellular level. This complexity makes it challenging to assess thyroid health solely through blood tests. Therefore, it is essential to incorporate additional thyroid testing methods alongside blood tests to gain a comprehensive understanding of thyroid function. For a more in-depth look into thyroid blood tests, including thyroid antibody testing and Hashimoto’s thyroiditis, I highly recommend my book, Test Your Thyroid Function. This resource provides you with the knowledge needed to confidently and precisely interpret your own thyroid blood test results.
Pulse, temperature and symptoms assessment:
Dr. Peat recommended a multifaceted approach to thyroid assessment, combining blood tests with pulse, temperature, and low thyroid symptom tracking for a more accurate picture of thyroid health.
Pulse and temperature of a person with good thyroid function:
By tracking body temperature and pulse rate, you can gain insight into how thyroid hormones are functioning at the cellular level. If your temperature is consistently below 98.6°F (37°C) and your pulse is consistently under 80- 85 beats per minute during the day, this may indicate low thyroid function.
Recognizing the Symptoms of Low Thyroid Function:
To accurately assess thyroid health, it’s also essential to evaluate the range of symptoms an individual may experience. Like pulse rate and body temperature, symptoms provide insight into how well the thyroid is functioning at the cellular level, where hormones directly affect energy production.
With hypothyroidism, cellular energy production decreases, leaving every cell in a low-energy state. This leads to widespread symptoms as organs and tissues struggle to perform optimally. Common symptoms of low thyroid function (hypothyroidism) include:
- Persistent fatigue
- Weight gain or weight loss
- Sensitivity to cold
- Muscle weakness and pain
- Hair loss
- Digestive issues
- Dry and thin skin
- menstrual problems
- fertility issues
- Low mood or Depression
- brain fog
- And much more
If you’d like to explore the various symptoms associated with hypothyroidism and learn how to track your thyroid health at home using pulse rate and body temperature, I strongly recommend my book, Test Your Thyroid Function. This book offers valuable insights for anyone already diagnosed with a thyroid condition or for those who suspect their symptoms may be linked to low thyroid function and a sluggish metabolic rate.
