A must-read if you suspect/know your thyroid is behind your fatigue, being cold constantly, dry skin + hair loss, irregular menstrual cycle, or unexplained weight gain.

The thyroid’s main job + how it goes awry

The thyroid is a little butterfly-shaped gland that sits nestled at base of your throat. Its most important job (though it has several) is to control your metabolism (the rate at which you burn energy), which is why the most frequently reported symptoms of low thyroid function are fatigue and befuddling weight gain (weight gain that seems to have no clear cause).

Most (~90%) of hypothyroidism or “low thyroid” function is an autoimmune condition called Hashimoto’s, where the immune system gets confused and starts attacking the tissues of your thyroid gland because it thinks it’s an invader or pathogen. This is what’s going on with all autoimmunity, the type of autoimmune condition you have is determined by which cells your immune system is mistakenly attacking (unfortunately people with autoimmunity often develop more than one flavor).

When your body attacks your thyroid gland, it damages and destroys the tissue there, making it harder for it to produce the hormones that regulate metabolism, T4 and T3 (stay with me). Your brain picks up on this and starts shouting louder and louder at the thyroid to PLEASE MAKE MORE.

But of course, it’s a brain, so that “shouting” happens via the brain secreting more and more and more of the regulatory hormone TSH. This is the number most frequently checked on bloodwork, and it tells us that there’s an issue, but not much more about the specifics. This is why I almost always like to see a full thyroid panel when someone comes to me with suspected or confirmed thyroid issues. So: if TSH is high, that means that the brain has clocked that there are not enough thyroid hormones in circulation, which is almost always due to the tissues of the thyroid gland being damaged or destroyed via an autoimmune attack.

“If TSH is high, that means that the brain has clocked that there are not enough thyroid hormones in circulation, which is (almost always) due to the tissues of the thyroid gland being damaged or destroyed via an autoimmune attack. ”

Other potential causes of “low thyroid”

Though the majority of “low thyroid” is due to Hashimoto’s, there are a couple other things that can be happening there that would cause TSH to be high. The thyroid gland could be totally fine, chuggin’ along, producing T4 and T3 like it’s supposed to, and you can still have symptoms that look like autoimmune thyroiditis. What’s happening here? Likely, something is affecting the T4 to T3 conversion. The thyroid gland itself produces mostly T4, which has to be converted into its “active” form, T3, in order to be used by each and every one of your cells. Several things can mess this up, but we’re going to talk about the two most important ones (imo): poor T4 —> T3 conversion and reverse T3 shunting.

Poor T4 (what the thyroid gland makes) to T3 (active, useable form) conversion is often thought to be due to an iodine deficiency, and I am here to tell you that this is usually not the case in the industrialized world. Unless you never eat seafood, use exclusively non-iodized salt, and never take a multivitamin, you’re probably getting enough iodine, and taking an iodine supplement can frequently make the autoimmune attack WORSE rather than better. It does not take much iodine to avoid deficiency - you should be getting 200mcg per day MAX from all sources combined. A much more likely deficiency that can lead to poor T4-T3 conversion is selenium. While most of us get enough iodine, many of us do NOT get enough selenium. Good news is, it’s a pretty easy fix - 2 or 3 brazil nuts daily has the perfect amount.

The second phenomenon that affects how much of the useable T3 you have available is chronic high stress. If cortisol is high enough for long enough, it starts to change how your body handles thyroid hormone: instead of going from T4 to T3 and being used, it converts T4 into reverse T3, which is effectively unusable and just so wildly unhelpful. You get the symptoms associated with low thyroid function, even though your thyroid gland might be doing okay. Reverse T3 is rarely tested on conventional bloodwork, so it just looks like your brain is yelling at your thyroid for no apparent reason. The solution to this is to lower your stress as much as is available to you, and take lots of Ashwagandha (order some here). Ashwagandha is a spectacular soothing nerve tonic, that also has been shown to mildly improve the T4 to T3 conversion, which will help you feel better sooner.

Thyroid shit is complicated, way more so than I can communicate in an article. It is becoming way more common than it used to (we don’t yet know why, but I have my theories) and you’re at a higher risk of developing it (and all autoimmunity) if you’re female. I’ve helped dozens of folks address their hypothyroidism and reclaim their energy and quality of life - check out Taylor’s testimony below. If you’d like to learn more about working with me and becoming a client, head here or click below.

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HYPOTHYROIDISM: What's happening in your body + bloodwork explained

A must-read if you suspect/know your thyroid is behind your fatigue, being cold constantly, dry skin + hair loss, irregular menstrual cycle, or unexplained weight gain.

The thyroid’s main job + how it goes awry

Other potential causes of “low thyroid”

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