Thyroid Basics: How it Works and What to Test
Do you have (or suspect that you have) low thyroid function?
Are you tired of feeling sluggish and foggy, only to be told that your thyroid tests “look normal”?
You are not alone! Thyroid health is one of the most common reasons patients seek my care - and for good reason! Optimal thyroid function is an essential component of your health and well-being.
Your thyroid gland is part of your hormone system (also referred to as your endocrine system). The thyroid gland is shaped like a butterfly and is located inside your neck over your windpipe.
Thyroid hormones play a major role in regulating many bodily functions, including:
Metabolism
Weight
Energy
Mood
Temperature control
Bowel function
Cognitive function
Heart health
Skin integrity
Muscle development
LOW VS HIGH THYROID
It is far more common to have low thyroid than high thyroid levels.
When you have a low-functioning thyroid, it is called hypothyroidism.
Symptoms of hypothyroidism include:
fatigue
dry skin
weight gain
constipation
“brain fog”
depression
A less common condition is hyperthyroidism, when your thyroid is over-active. Symptoms of hyperthyroidism include:
weight loss
“bulging” eyes
hot flashes
rapid or racing heartbeat
anxiety
UNDERSTANDING THYROID TESTING
TSH = Thyroid Stimulating Hormone
Many of my patients misunderstand this test. It’s an “oppositte” test, and it’s confusing!
TSH is made by your brain, not by your thyroid. Your brain makes TSH when it senses that your body needs more thyroid hormone. The TSH made by the brain sends a signal to the thyroid to make more thyroid hormones.
When thyroid hormone levels in your body are low, the brain makes TSH "turn on" your thyroid.
High TSH = body needs more thyroid hormone
Low TSH = body does not need more thyroid hormone
The TSH is important, but you need to test beyond the TSH to get a full picture of thyroid function.
While many conventional practitioners only test the TSH to evaluate thyroid function, relying on the TSH alone does not give you a complete picture of thyroid function and may miss a certain percentage of people with low thyroid hormone. This is why I routinely see new patients with classic symptoms of low thyroid who have been told repeatedly that their thyroid testing is “normal,” but when we test a more comprehensive thyroid panel, a picture of low thyroid function is unveiled.
T4 and T3 Hormones
Your thyroid makes different types of thyroid hormones. The two most important are T4 and T3.
Here’s what you need to know about T4 and T3 hormones:
You make much more T4 than T3
free T4 hormone gets converted in your tissues to free T3 hormone
T3 is far more active than T4
(the lab tests shown here are taken from a patient of mine who had this issue)
Why does this matter?
If you have a normal TSH but a low free T3 hormone, you will have all of the symptoms of low thyroid (hypothyroid) even though your doctor tells you your thyroid function is “fine”!
BOTTOM LINE:
Test beyond the TSH.
Know your levels of free T3 hormone.
Speak up! Ask for the tests that you need.
My standard thyroid laboratory testing typically includes:
TSH
Free T4 and T3 hormones
Anti-thyroid Antibodies
Additional testing often ordered includes:
Reverse T3 (which “hides” T3 and prevents it from doing its work)
Levels of nutrients important to thyroid health, including zinc, selenium, iodine, and more
Levels of toxins such as mercury, which can interfere with thyroid health
Now that you know the "Thyroid Basics” are you ready to learn more about your thyroid health?
As a board-certified Integrative & Functional Medicine physician, I can help you “think outside of the box” and dig deeper with a variety of laboratory testing to help uncover the underlying root causes of your symptoms and create a plan personalized for you that goes beyond the prescription pad to incorporate diet/lifestyle change, nutritional supplements, holistic therapies, health coaching and more! Contact us to schedule an appointment or learn more.