What you likely do know
The thyroid is an endocrine gland – it is an organ that produces hormones. The thyroid produces thyroid hormones, T4 (thyroxine) and T3 (triiodothyronine), that control metabolism.
Hypothyroidism means there isn’t enough thyroid hormone. Hypothyroid is NOT fun. It causes you to feel tired, unmotivated, depressed, cold, and to gain weight and lose hair. It may also cause a slow pulse, constipation and morning headaches.
Hyperthyroidism means there is too much thyroid hormone. You’d think that the opposite of all that depressing hypothyroidism would feel great… but no. Hyperthyroid can cause you to feel anxious, agitated, sleepless, sweaty and lose weight in an unhealthy way. It may also cause a speeding pulse and make working under pressure feel impossible.
Conclusion – thyroid hormones should stay in a perfect little goldilocks range for optimal emotional and physical health.
What you might not know about your thyroid
1. TSH is NOT a thyroid hormone
Ordering TSH is the standard of care for thyroid symptoms and it is usually the only thyroid marker that will be initially run or approved to be covered by insurance.
The problem? TSH is NOT a thyroid hormone. TSH is Thyroid Stimulating Hormone, the hormone produced by the pituitary to stimulate the thyroid.
Think of the thyroid as a car and its hormonal output as speed. In this case, the pituitary is the driver. However, unlike most drivers, the pituitary doesn’t have access to a gas pedal and a brake, it only has the gas. TSH is the gas pedal. If the speed is too slow, the driver steps on the gas to force the car to go faster. If the speed is too fast, the driver steps off the gas to let the car slow down. The same is true in the body – if there isn’t enough thyroid hormone (T4 and T3) in your blood, the pituitary “steps on the gas” and produces more TSH to tell the thyroid to “go faster” and produce more hormone. If there is too much thyroid hormone in your blood, your pituitary steps off the gas, produces less TSH and lets the thyroid take a break.
TSH acts as reverse indicator for the thyroid. The assumption is that high TSH means hypothyroid and low TSH means hyperthyroid. I say assumption because TSH only tells us if the driver is speeding up or slowing down, but gives us no direct information about the speed of the car. We need to actually measure a thyroid hormone to understand what the thyroid is doing.
T4 is the best lab marker for insight into the thyroid’s function, but it isn’t the only thyroid hormone.
2. Your thyroid symptoms may not be your thyroid’s fault
I specifically define hypothyroid as a lack of thyroid hormones instead of as a lack of thyroid function. If your T4 is normal, your thyroid is doing its job. You still may have hypothyroid symptoms from a lack of T3, but a lack of T3 is NOT the thyroid’s fault.
The thyroid produces T4, but T4 isn’t your active thyroid hormone, T3 is. Your thyroid does produce some T3, but the large majority of your T3 hormone is converted from T4 in the liver (and some in the gut). If your thyroid is doing its job producing adequate T4, but your liver isn’t doing its job converting T4 to T3, you will still have hypothyroid symptoms because you are missing the potent, active form of your thyroid hormone.
And the liver isn’t the only thing that impacts your T3 levels.
3. Stress can cause hypothyroid symptoms
If you are experiencing high levels of stress (read – are a human in the 21st century), “burning the candle at both ends” and are in danger of burning out (looking at you, millennial burnout generation), your adrenals are working even harder than you are. This season of high stress is manageable thanks to cortisol, the “can do” adrenal hormone, but if this goes on too long, you are in danger of adrenal exhaustion. The body will give some important cues along the way to take a break, vacation, or stop saying yes to so many things by giving you illness, fatigue, and anxiety. But if you still press on at this unsustainable pace, the thyroid will act as a break to protect the adrenals. When levels of cortisol get too high, instead of making T3, your active thyroid hormone, you make reverse T3, an inert, useless thyroid hormone. This will cause severe hypothyroid symptoms. In an effort to prevent adrenal exhaustion, your body will use the thyroid to make you so tired, so cold and so depressed that you have no choice but to stay in bed and take that break your body is dying for!
Your symptoms are messengers. Don’t shoot the messenger.
But what happens when instead of listening to your body and taking the adrenal and life preserving break you so desperately need, you go to your doctor to see if they can fix your symptoms? They do some lab work and find that your TSH is high (because you aren’t producing enough T3) so they prescribe synthetic thyroid hormones. With your thyroid pills (often cited to be the most commonly prescribed antidepressant) you now have your energy and motivation back, so you are free to resume your unsustainably stressful lifestyle, endanger your adrenals further, and have lifetime sentence of thyroid medication – when, oh wait, you never. had. a. thyroid. problem.
Far too often the thyroid is blamed for adrenal fatigue.
You must look at T3 levels to avoid blaming adrenal problems on the thyroid!
This is why I always recommend the following to my clients as minimum labs needed to understand the real cause of hypothyroid symptoms:
TSH, thyroid stimulating hormone (pituitary hormone)
Free T4, thyroxine (thyroid hormone, tells us if your thyroid is doing its job)
Free T3, triiodothyronine (active thyroid hormone, tells us if your liver is doing its job)
Reverse T3 (inactive thyroid hormone, tells us if your adrenals are causing a problem)
I sincerely hope you are not dealing with hypothyroid symptoms, but that if you are, this information empowers you to dig deeper before blaming your thyroid!