The thyroid gland and its many associated hormones can be thought of as the “traffic center” for your endocrine system. Thyroid hormones are important in their own right, especially for regulating metabolism. But healthy thyroid function is also critical to the balance of your other hormones. When something is out of whack elsewhere in your endocrine system, the thyroid gland will work hard to compensate.
The Facts about Thyroid
- Being low thyroid frequently goes hand in hand with imbalances in other hormones.
- There is a symbiotic relationship between thyroid and other hormones. Treating other hormones without checking thyroid is not an effective way to balance hormones.
- Many symptoms of low thyroid overlap with symptoms of other hormone imbalances, including fatigue, weight gain, irritability, depression, anxiety, insomnia, and brain fog.
T3 and T4
T4 is the thyroid hormone that your thyroid gland produces directly. After T4 is secreted by the thyroid gland, it flows through the pituitary. When the pituitary senses that the body doesn’t have enough T4, it releases thyroid stimulating hormone (or TSH). TSH then stimulates the thyroid to produce more T4. Proper functioning of this feedback loop is the first piece of the thyroid puzzle.
But there’s more. T4 is not the thyroid hormone that your body actually uses—or at least not the primary one. T4 has to be broken down into another thyroid hormone called T3; and then T3 is broken down into yet another thyroid hormone called T3 free. T3 free is the thyroid hormone your body actually uses. You can have all the T4 in the world; but if it isn’t converted to T3 free, you may as well have none at all.
One of the reasons thyroid levels decline with age is because the thyroid and pituitary start to slow down. However, as the body ages, it also becomes less efficient at converting T4 to T3 free.
Why Low Thyroid Falls Through the Cracks
Low thyroid is frequently undiagnosed or treated incorrectly in adults because most healthcare practitioners follow outdated protocols. Here’s what they’re missing:
- T4 only accounts for about 20% of thyroid function in the body.
- T4’s primary function is to be broken down into T3, and then T3 free.
- T3 free accounts for 80% of thyroid function in the body.
- As the thyroid ages, it produces less T4. However, there are also chemical changes taking place in the body that inhibit T4’s breakdown into T3 free.
- Most healthcare practitioners only measure T4 levels and the feedback loop between TSH and T4. They miss 80% of thyroid function by not testing for T3, and its functional form, T3 free.
- When the same healthcare practitioners do treat for low thyroid, they prescribe synthetic T4. They may achieve adequate levels of T4 with this approach; but if the body isn’t breaking the T4 down into T3 free, the end result will be suboptimal.
- What most healthcare practitioners consider a normal level for thyroid isn’t usually high enough. For thyroid, the upper end of lab-tested ranges is usually healthiest.
Unfortunately, all of the above results in many people being inadequately tested and treated for low thyroid, if they’re being tested and treated at all.
Treatment for Low Thyroid
Has your primary care physician checked your thyroid and said it’s fine? It may not be. This is why we always check T3 free. If T3 free is low, our doctors will provide the treatment that was needed all along, using bioidentical thyroid that contains both T4 and T3, in a dose that will get levels to the upper end of lab- tested ranges. There are many facets to better aging. Thyroid is one of them.