Your Thyroid: The what, why, where, and how it controls your hormones


Gang, let’s be honest. Hormones are pretty much in control of your entire being, from your cardiac health to your digestive system and everything in between. But they’re not just running around, having a laugh, and seeing how bad they can make you feel. They’re actually taking orders from a command center, a gland that’s almost at the very top of the Endocrine tree. Welcome to your Thyroid gland.

Your Thyroid’s in charge

As regular Hormona may know, your hormones are chemical messengers that relay information to and from your cells. They travel your entire body, ensuring your cells are working well, and that your body is functioning at optimal levels by passing on that information. But where are they getting it?

All of your hormones, regardless of which system they’re involved in, be it reproduction, digestion, or metabolism, take their orders from higher up the chain of command also known as your Endocrine system. At the very top, the big boss, is your Hypothalamus gland. Next in command is your Pituitary gland, and both are located in your brain.

But the gland that’s actually in charge on the ground, so to speak, is your Thyroid. It takes orders passed from your Pituitary and Hypothalamus and turns them into hormones that can affect the physical changes requested, before passing info back up the chain.

It’s located at the base of your neck, nestled in the little dip in your collarbone. And from there, your Thyroid controls everything your body does. Frankly, it’s an amazing gland that multitasks like an absolute boss.

How does your Thyroid work?

And here’s how it does that. In order for any of this work to happen, you first need to enjoy some Iodine-rich foods. And you need to do that because the hormones your Thyroid produces need Iodine to exist. The thing is, we don’t actually produce it, so eating it is the next best way to get it.

Conveniently delicious Iodine-rich foodstuffs include:

  • Chicken
  • Milk
  • Eggs
  • Seaweed
  • Liver
  • Canned tuna

Once you’ve added sufficient Iodine to your body, the magic can begin. While your Thyroid is in charge on the ground, as we mentioned, it’s taking orders from the glands in your brain. Those orders take the form of Thyrotropin-Releasing-Hormone, or TRH from your Hypothalamus, which kick-starts the production of Thyroid-Stimulating-Hormone, TSH, in your Pituitary gland. And it’s the TSH in your blood that your Thyroid responds to.

This is where that delicious Iodine comes in. On receiving those orders, your Thyroid uses the Iodine to produce its two master hormones. They are: Thyroxine, AKA T4, and Triiodothyronine, or T3. It doesn’t produce them at an equal rate, however. The ratio is actually 80% T4 to 20% T3. Which sounds odd, but there is a reason for it. And it’s a doozy.

Thyroid hormones

Now, T4 and T3 are essentially the skeleton keys that unlock all of your cells. They can pass information to and from any part of your body. And while they’re both hormones produced and distributed by your Thyroid gland, they are very much not the same.

The best way to think about it is this: T4 is the great communicator. It can talk to and take info from anywhere in your body. But it has one slight flaw. It cannot affect any physical changes. So if your cells aren’t working as hard as they should be, T4 can tell your Thyroid that, but it can’t make your cells speed up.

Where T4 talks an amazing game, T3 actually plays it. Or more specifically, T3 is the hormone that will make your sluggish cells pick up the pace. Medical types refer to it as biologically active, meaning that it can physically change the behavior of your cells when told to. But as we mentioned, you don’t make a huge amount of the stuff on a regular day. So what happens if you don’t have enough?

Well, here’s where T4 steps up. Because although it can’t change cells, T4 can change itself. Into T3. Yup, your Thyroid can command your T4 to become T3 until you’ve got enough to be working properly. And then it’ll go back to just being T4. Amazing, no?

How Thyroid hormones control everything

So, now you know how Thyroid hormones can get into all of your cells in one way or another. But what does that mean for you in a physical stylee? Well, it can mean everything. Your Thyroid’s reach means that it’s able to regulate your metabolism, those sluggish cells we talked about. But it also regulates reproduction, digestion, movement, muscle and bone health, heart rate, your temperature, and even how well your brain is working.

As one of the commanders of your Endocrine system, your Thyroid is incredibly powerful. And your body needs to maintain a super-delicate balance to keep everything working properly. Too much or not enough Thyroid hormone can lead to a host of health issues.

Parathyroid what?

Your Thyroid gland is amazing, but it’s not working alone. Although it’s hard to believe there’s anywhere near enough space, there are in fact four more Endocrine glands in your neck. They’re your Parathyroid glands, and are attached to, although not part of, your Thyroid gland. And they do some important work of their own.

These small but crucial glands are also part of your Endocrine system, although their role is very specific. And it’s simply to regulate the amount of calcium in your body by producing Parathyroid hormone. While that sounds like a rubbish job, it’s crazy vital to your wellbeing.

Calcium levels are important for bone health, of course. But they’re also intimately involved in your intestinal and kidney health among others. So keeping your calcium at the right level for you is essential for lots of reasons. And having your Parathyroids working well, alongside and in conjunction with your Thyroid is just as important.

How is Thyroid dysfunction diagnosed?

Ideally, Thyroid dysfunction is diagnosed after careful discussion of your symptoms and a comprehensive blood test. The test, otherwise known as a Thyroid function test, looks at up to five thyroid-related levels. We say up to, because depending on where you live, you may not get the full array. Britain, we’re looking at you.

In general terms, the five levels are:

  • T4, also known as Thyroxine
  • T3, or Triiodothyronine
  • TSH, or Thyroid-Stimulating Hormone
  • TSI, or Thyroid-Stimulating Immunoglobulin
  • Antithyroid antibodies

Blood results

The results will be compared to typical levels, according to your physician’s data, and along with your symptoms, you’ll get a diagnosis of over, under, or neither. The problem is, this isn’t an ideal world. And this is not an ideal system. We’ve no idea who came up with the typical ranges, and we know for a fact that everyone’s typical range will be slightly different. So, there’s that.

Plus, blood tests take days to analyze and return results, and by the time you get them, they’re very much out of date. Why? Because your hormone levels change hour by hour and can be affected by each other on a daily basis. Without regular, immediate testing, all they really show is a snapshot of your levels during one minute of your life. How does that help?

Then add in medicine’s tendency to only consider the numbers and not really take physical and emotional symptoms into account, writing them off as unrelated, and what you end up with is a bunch of very ill, mostly women.

We’re going to change that particular situation, so watch this space, gang.

When your Thyroid goes wrong…

So as you may have guessed, your entire Endocrine system is working on a very delicate balance. And as the workhorse of the system, your Thyroid gland is substantially more likely to run into trouble. Which is really the only time you should ever be aware of its existence.

That trouble, though, can take many, many, many forms. From overt weight gain, ticks, twitches, and pulse rates that scare the daylights out of doctors, to the less obvious weight loss, mood alterations, and period changes, Thyroid issues are plentiful. In fact, around 20 million Americans will experience Thyroid dysfunction at some point in their lives. And that’s just the ones that are able to get a diagnosis.

For the most part, though, that trouble will come in one of three categories: Overactive, Underactive, and Cancer.

Thyroid cancer

This is incredibly rare, but it’s clearly the scariest of the three, so we thought we’d get this one out of the way first. Of course, the scariest part is whether it’ll end your life, and the chances are that it won’t. If caught early, Thyroid cancer is entirely curable and shouldn’t affect your lifespan. It is, though, about three times more common in women than men.

Characterized by a swollen gland and a scratchy, sore throat that won’t go away, Thyroid cancer is divided into four different types: papillary, follicular, medullary, and anaplastic. Papillary is the most common and survivable, whereas anaplastic is the rarest, and as it turns out, the most deadly. Medullary is the only form that has a genetic link.

And as for causes, outside of genes, no one’s really sure exactly what turns a healthy Thyroid into a cancerous one. Obesity, radiation exposure, and an overabundance of growth hormone can play a part, but it’s definitely not caused by other Thyroid conditions.

Treatment ranges from Chemo and Radiation therapy, to removal of your Thyroid gland and affected tissues. And the five-year survival rates are really good, around 70-90% for all but the anaplastic forms.

Overactive Thyroid

Now we’re into the slightly more common forms of Thyroid so-called dysfunction. And by slightly more common, we mean a literal ton more common. Where Thyroid cancer will affect around 40,000 Americans a year, an overactive Thyroid claims around 1% of all 330 million Americans over the age of 12. Yes, over the age of 12. It’s so common, they’ve added children to the stats.

In the UK, the rate is 1 in 50 women, because, you guessed it, an overactive Thyroid is more common in women than men.

Here’s where it starts to get complicated. An overactive Thyroid, technically known as Hyperthyroidism, actually comes in three different forms. They all have the same symptoms and the like, but the treatments can vary. Ready? Here we go.


The first is regular old overactivity, where your Thyroid gets a little het up and produces way too much of everything, and also gives out random info to your cells. That can cause havoc with your metabolism, speeding everything up. And while that might sound like a benefit, it also comes with added nausea, increased pulse rate, vomiting, irregular periods, extra PMS, mood swings, personality changes, acne, dry skin… The list is endless.

After diagnosis, treatment can include medications like Carbimazole to help nudge your Thyroid back to more typical behavior. If that doesn’t work, depending on the severity of the symptoms and your age, therapies involve partial or total removal of the Thyroid, or ingestion of radioactive Iodine, to put a stop to your Thyroid altogether.

At that point, though, you’ll need to take some kind of Thyroid hormone replacement to help your body recover what it’s lost. And that’ll likely be something you do for the rest of your life.

Subclinical Hyperthyroidism

Now, technically, this is a situation where your TSH levels are super-low, but your other Thyroid hormone levels are within the typical range. Which means you may or may not have the characteristic overactive symptoms, and may or may not need treatment. This situation generally resolves itself after a few months, but if your TSH levels become undetectable, you’re far more likely to graduate to full-on overactivity.

Graves’ disease

Despite its frankly terrifying name, Graves’ disease is named after the physician who discovered it, and not because that’s where you’ll end up. At least, you won’t if you get treatment. And that’s because Graves’ disease is an Auto-immune form of Hyperthyroidism.

Why is that so serious? Auto-immune conditions basically involve your body attacking parts of itself. And in the case of Graves’ disease, your immune system attacks your Thyroid gland as if it were an invader, causing all sorts of damage. It comes with all the usual overactive symptoms, but at much higher severity, and a risk of heart attack, thanks to the ridiculously high pulse and heart rates.

Left untreated, Graves’ results in a diseased and dying Thyroid gland that leeches poison into your system while your body exhausts itself trying to fix and/or kill everything.

Treatments include Beat Blockers to support cardiac health, as well as the usual surgery and iodine. Lifelong hormone replacement therapy follows, as does a period of underactivity. Which leads us neatly on to…

Underactive Thyroid

If you thought overactivity was shockingly common, get ready to have your mind blown, gang. There is, of course, an equal and opposite to Hyperthyroidism, and it’s rather catchily known as Hypothyroidism, or underactivity. And believe it or not, it’s FIVE times more common that its overactive counterpart. Yup, 5% of US residents over 12 will see some underactivity during their lives.

But what’s worse is that at least another 5% are living undiagnosed. So, we’re now looking at an incredible 10% of the population in America alone affected by an underactive Thyroid. Mind blown, right?

And just like its overactive colleague, Hypothyroidism also comes in three forms, and all have similar symptoms.


The first in our underactive trio is plain old underactivity. This, essentially, is what happens when your Thyroid doesn’t produce enough Thyroid hormone, causing a slowing down in your cells. And just like Hyperthyroidism, this can lead to a cascade of issues, not least of which is weight gain. Then there’s the exhaustion, depression, brain fog, constipation, irregular periods, low heart rate, never being warm, and muscle weakness… Again, the list is endless.

Causes are usually down to certain medications or viral infections, as well as previous Thyroid issues, including surgery. If left untreated, underactivity can be deadly. It can slow your heart rate to a stop. And that’s why those figures are so scary. Treatments, though, can be super-effective and mostly include Thyroid hormone replacement.

Subclinical Hypothyroidism

You’re probably way ahead of us here, but subclinical Hypothyroidism occurs when your TSH level is a little high but all your other Thyroid hormone levels are within typical ranges. It comes with all of the same symptoms, or none, depending on how high your TSH is.

Having subclinical underactivity doesn’t necessarily mean you’ll end up with the full underactive experience, and your levels may well stabilize with treatment. And that’ll likely involve Thyroid hormone replacement.

Hashimoto’s Thyroiditis

Perhaps the most common form of underactivity, Hashimoto’s Thyroiditis is, you guessed it, the Auto-immune version of Hypothyroidism. And just like Graves’, it can cause a host of symptoms, including a painful and swollen Thyroid. The problem with Hashimoto’s is that it’s an incredibly slow-moving condition, and it can take years to identify the symptoms and get a diagnosis.

The symptoms are exactly the same as Hypothyroidism, but with the added benefits of your body attacking itself over the course of years. And misdiagnosis, or delayed diagnosis, of Hashimoto’s can be equally as dangerous as underactivity.

Treatments generally include Thyroid hormone replacement, or surgery in the case of a severely swollen gland that makes swallowing difficult.

Thyroid dysfunction treatments

Now, we’ve mentioned Thyroid hormone replacement several times, which sounds pretty self-explanatory. And, on the surface, it totally is. It basically consists of taking supplemental Thyroid hormones to replace what you’ve lost, and helping your body function as it should.

But as with all things hormones, it’s deceptively simple. As we mentioned, everyone’s optimal levels will be different. So, falling in average ranges after taking meds may work for you. But there are plenty of people who find that average just makes them sick. So there’s that.

Then there’s the actual hormones you’re taking. For a few years now, there’s been some serious discussion about the recommended treatment for thyroid dysfunction, and it breaks down to one hormone vs. two. Many physicians prescribe only T4, as your body will convert it into the T3 it needs. That, though, also doesn’t work for a large percentage of patients. But combination therapy, T4 with some added T3, is rarely offered.

And finally, there’s always been a debate around the efficacy of synthetic hormones, versus their natural if slightly icky counterparts. Made from the desiccated Thyroid glands of pigs, the natural therapy is more effective and it’s a combination therapy. But it’s not available everywhere.

Honestly, we could go on about this for days, but frankly, your treatment decisions should be yours, and right now, for the most part, they aren’t.

Your Thyroid needs you

Even if you’ve never had a Thyroid symptom in your life, there are still plenty of things you can be doing to support your Endocrine system’s workhorse. Eating a nutritious diet, supporting your immune system, sleeping and exercising can all give your hormones a boost.

But if you recognize anything we’ve talked about today, please talk to a healthcare type and see what might be going on. A diagnosis might take some time, but it’s well worth pursuing. And keeping track of your symptoms and hormones can make all the difference when it comes to medical types — our Hormona app exists for this exact situation.

Your Thyroid needs you to help it stay healthy, and trust us, you want it to stay healthy. So get tracking!

Disclaimer: This website does not provide medical advice. The information, including but not limited to, text, graphics, images and other material contained on this website are for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment, and before undertaking a new healthcare regimen, and never disregard professional medical advice or delay in seeking it because of something you’ve read on this website.

Posted By  : Emma Matthews

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About the author

Emma Matthews

Emma Matthews

Emma Matthews is a seasoned freelance writer and editor who first became obsessed with hormones following a Graves Disease diagnosis age 21. She has, since then, discovered that obsessing about her health doesn’t pay the bills, so she put her other obsessions - TV, True crime - to good use. She’s written for, among others, the Den of Geek, Buffy, CSI, Supernatural and Stargate Magazines, as well as the Crime and Investigation Network. She’s currently lamenting the coming end of Brooklyn Nine-Nine, but thanks the universe that we’ve still got Drag Race. Even if Michelle Visage won’t talk to her…

About the author

Emma Matthews

Emma Matthews

Emma Matthews is a seasoned freelance writer and editor who first became obsessed with hormones following a Graves Disease diagnosis age 21. She has, since then, discovered that obsessing about her health doesn’t pay the bills, so she put her other obsessions - TV, True crime - to good use. She’s written for, among others, the Den of Geek, Buffy, CSI, Supernatural and Stargate Magazines, as well as the Crime and Investigation Network. She’s currently lamenting the coming end of Brooklyn Nine-Nine, but thanks the universe that we’ve still got Drag Race. Even if Michelle Visage won’t talk to her…

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