Thyroid 101


Hello and welcome to my blog. This an introduction to the thyroid gland, thyroid hormones, what happens when it malfunctions and which test to get if you think you have a thyroid problem. 20 million or more people in the US have thyroid issues and many are un-diagnosed, meaning there is a lack of understanding in the medical community on this topic. I worked in a laboratory where someone used radioactive iodine, which they were not careful with and it affected her co-workers thyroid glands, this is when I got interested in the thyroid.

The thyroid is a gland in the neck which produces hormones that  regulate metabolism so is one of the master glands in the body as so many functions depend on a good thyroid gland. Thyroid hormones, in a nut shell run your metabolism by allowing oxygen to enter cells so they can make energy. It is like a gas pedal in a car, the thyroid drives your metabolism.

Untreated or chronically low thyroid leads on or is linked to other illnesses and other hormone imbalances such as insulin resistance and adrenal fatigue. Low thyroid function have cost people their jobs, relationships and happiness as having a non-functioning thyroid is like a giant good mood hoover.  People with thyroid problems are not fun to be around, but it is not their fault.

Symptoms of low thyroid are

  • Fatigue
  • Being cold
  • Feeling bloated
  • Constipation
  • Weight gain
  • Brittle hair and nails
  • Depression
  • Brain fog
  • Slow to process words
  • Slow to think of what to say
  • Dyslexia like symptoms
  • Poor coordination
  • Being tearful
  • Pain
  • Slow healing
  • And more


I could write a whole book on thyroid dysfunction as its a big topic, luckily several other people have written great books on this topic. The thyroid is fundamental to healing and health, like the gut that if there is something wrong with your thyroid hormones it will hinder many other processes in the body, even if you ‘do everything else right’. Thyroid function is key in weight management and this is overlooked by many doctors as they just tell their thyroid patients ‘Exercise more, lose some weight, eat healthily’  or ‘Your thyroid is fine its all in your head’. Many people who work out for an hour a day and eat a sensible diet or a 1000 kcal a day and are still fat often have an un-diagnosed thyroid issue.

Modern medicine works on the 2 standard deviations model, so you need to have really really low levels in blood tests for your doctor to flag the result. It is almost like a child at school who keeps getting Es and Fs in test results, only then does the teacher offer help, when they should offer the child help when he or she gets Cs and Ds. Blood tests are a bit like that, you need to be sicker than the average sick person. This is why you must look up the ‘optimum range’ for any lab test, to avoid being fobbed off.

This is becasue lots of doctors do not fully understand how the thyroid and its hormones work, exactly which tests to do or how to treat it. Sometimes they do know what to do but it is just too complicated and they just do not have time.  Just giving patients  thyroxine or T4  alone doesn’t work a lot of the time as so many things can go wrong in the thyroid pathway. 


The thyroid gland is under the control of the hypothalamus and the pituitary gland, so thyroid problems can begin here! When the pituitary gland in the brain senses low thyroid hormones in the blood, it releases thyroid stimulating hormone (TSH) which then tells the thyroid gland to make thyroid hormones. Two of the main thyroid hormones in the body are thyroxine (T4) and the  metabolically active triiodothyronine (T3). The T4 is like a coffee bean and the T3 is like the useful ground coffee. 

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T4 Thyroxine
T3 Tri-iodothyronine Active
T3 Tri-iodothyronine

When TSH tells the thyroid gland to make hormones, it makes about 90% T4 & 10% T3. T4 has to be transported out of the thyroid gland into the blood steam and carried in special transportation molecules. T3 is made  by enzymes, which convert  T4 into T3 by clipping off an iodine, both the conversion and the transportation  process can and do go wrong.

The liver converts about 60% of the T4  into active T3, and the gut converts about 20%. This means that gut issues like leaky gut or IBS, and/or a liver burdened with toxins are going to affect your T3 levels, and thus your metabolism. Some people have enough thyroxine to pass a thyroid test but are still only functioning at 70% so still feel crap and still have an under performing thyroid gland. Other people pass the standard TSH T4 test so are told ‘Your thyroid is normal’ but  their bodies can’t covert T4 into the  active T3 so they still get symptoms and feel dreadful.

There are other thyroid imbalances that can occur too such as  Hashimoto’s syndrome which is an autoimmune condition where the body attacks the thyroid gland, which often goes un-diagnosed when in fact about 80% of thyroid issues are a result of ‘autoimmunity’.

T3 is the hormone cells need to ‘make and use energy’ in the body, so T3 has to be able to communicate with the cells.  If the target cell membranes are damaged by  or weak then T3 can’t do its job. This damage can be from oxidative stress, free radicals or too much poly unsaturated fats in your cell membrane.

If you think you have a thyroid problem or have Hashimoto’s the very first step is to take a thyroid panel blood test. Here are the blood tests you need to have to get a better understanding of what has gone wrong and possible ways to fix the your thyroid problems. In the US it cost about $150, its more in the UK and less in other countries. With any blood test result you want to make sure your levels of whatever you are testing are optimal, not ‘within normal range’, as they are not the same answer. You can be ‘within normal range’ and still have a problem, as the size of this ‘range’ is pretty big. I once asked for these blood tests about 3 yrs ago and the Dr looked at me like I had three heads. 

  1. Free T4
  2. Free T3
  3. TSH
  4. TPO antibody
  5. TG antibody
  6. TBG Thyroid Binding Globulin (Transporter)
  7. Reverse T3

It is important to measure free T3/4 as if the thyroid  hormones are bound to other molecules then they arent able to do their jobs. TSH is the signal to the thyroid gland to make hormones. High TSH means the brain is shouting for thyroid but for some reason it is not being made.High TSH is also a sign inflammation is high. Low TSH can be the result of starvation (AKA low calorie diet) or too much exercises so the body is preserving energy. About 0.4-2.5 is a suitable range.

TPO and TG antibodies are to look and see if you have Hashimoto’s or autoimmunity, so the lower the better. Below about 15.

TBG Thyroid Binding Globulin is what the thyroid hormones ride around the body on, a bit like a boat. If the is a shortage of transporters then this means the thyroid hormones can’t get to their destinations.

Reverse T3 or RT3 is an isomer of T3 so it has the same atoms but a slightly  different shape, and acts  like an inactive form of T3. RT3 is  “antithyroid” as it bind to the same receptors as T3, sits there, and nothing happens. So, it blocks the thyroid effect. It is extra information in the puzzle for doctors or functional medicine doctors to help patients with thyroid issues.  Reverse T3  is like an antibody to T3, so halting your metabolism. Reducing stress will help reduce Reverse T3. Stress is not just relationships, finances but also environmental toxins, pesticides, heavy metals, food intolerance,  antibiotic residues and unstable blood sugar.

Many doctors are not expert in thyroid hormones so it requires some persuading to get a RT3 test, but it provides useful information. Below are the results as you need the ratio of T3 to RT3, so the ratio of useful T3 to useless T3.

Free T3/RT3 = 0.2 and above is ok

Total T3/ RT3 = 10 and above is ok

Testing just T4 and  TSH alone do not give satisfactory answers to people with thyroid problems, which is why 100s of millions of people in the world have un-diagnosed thyroid problems and just put it down to ‘getting older’ or ‘chronic fatigue’ or ‘slow metabolism’ or ‘moody’, when there is a real hormone imbalance going on.

To make all this more complicated thyroid problems are intertwined with adrenal fatigue, so that means there is cortisol, insulin, glucose, steroid hormones all in the mix too, but I can’t cover them in this blog as it gets too confusing. Chronic fatigue, pain, depression and fibromyalgia are all linked to adrenals and thyroid too. 


I will be writing other blogs on hormones and biochemistry so keep a look out if you are interested.  I’ve got a lot more information on how to help the thyroid and heal other systems in the body in my book which will be out in April.


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