“But my doctor says my thyroid is fine”
The thyroid is a complex and intricate topic, so let me preface what I’m about to write by saying that nothing I tell you could possibly take the place of sound medical advice, as there are exceptions and nuances of a stringent medical nature to several points I am going to discuss. I do hope, nonetheless, that reading this will have you question your conventional doctor’s assessment of thyroid regulation of metabolism early on in the game, when managing thyroid conditions without medication may still be feasible. I’m here to merely divulge relevant information with regards to thyroid testing, drawn from reputable sources within the scientific community, in hopes of helping you source the right labs and seek out the right healthcare providers for your specific case.
A cushy number
I truly wish I had a dime for every time I’ve heard the following: “I eat healthy, I go to the gym and lead a fairly active lifestyle, but that needle on the scale just won’t budge, if not in the wrong direction. I have severe fatigue, insomnia and daytime sleepiness, heart palpitations, anxiety, depression, brain fog, mood swings, digestive issues and dry skin. My hair is visibly thinning out and my libido has left the building. But my doctor checked my TSH and he says my thyroid is fine”. This is the point in the conversation where I usually have to take a 4-o loooong, 3-e deeep breath and try to remain calm. No, I do not blame any woman for getting defensive when I tell her she needs her thyroid re-tested, it is a natural reaction stemming from the fact that we still carry an ancestral torch for medical doctors - and to a massive extent, it’s right that we should. In fact, I most certainly do not oppose allopathic medicine, but I do frown upon physicians who treat the human body as a set of separate blocks, and do not listen to their patients or investigate what is upstream of their health issues. And all it would take, to kick off a thyroid investigation, is running more labs than just TSH right off the bat, and evaluating them by reference ranges that reflect modern standards, rather than parameters dating back to the 1950s.
Upon being diagnosed by their medical doctor with a thyroid condition at the eleventh hour, after years of feeling like crap and living a dysfunctional life, many of the thyroid patients I know have been gleefully sent home with a prescription for thyroid hormone, and told to hope for the best. If, or rather when their condition worsens, the doctor will dismissively up their medication and tell them to come back in a few months to see how they’re doing. For way too many people, medication does not optimize their thyroid, and that ‘let’s hope this time it takes’ pattern becomes their way of life. Functional medicine, on the other hand, runs labs on certain biomarkers, which I will detail ahead, typically deemed unnecessary by mainstream medicine, notably by the Big Pharma/health insurance cartel, unless warranted by advanced disease state. As it were, medical doctors in countries with socialized medicine handle things no differently. These values may provide an insight into what your thyroid is doing in relation to other systems, and if you are on medication, whether or not it’s the right one for you.
Thyroid 101
I couldn’t possibly talk about thyroid testing or nutrition and lifestyle interventions, without explaining the basic ways in which the thyroid performs its metabolic duties.
Most of you have, at some point, heard of the thyroid being referred to as the ‘master conductor’ of all body systems. While that is an accurate job description, it could be somewhat misleading, as it might suggest that it ‘works alone’. For starters, the thyroid responds to commands coming from the brain that instruct it to jumpstart vital cellular processes in the human body, and it reports back to the brain in a constant feedback loop, so that the brain knows whether to increase or decrease its signaling. In the cells, thyroid hormones perform in accordance with genetic instructions, and as a function of epigenetic influences (lifestyle, environment and diet), balance and interplay of steroid hormones, gut health, immune system efficiency, physiological and emotional traumas, and even social connections. In essence, the thyroid doesn’t just make peremptory decisions, it choreographs its management of body processes as informed by external and internal events. You could say there is always a reason for the way the thyroid behaves, good or bad, as it always honors and prioritizes survival and reproduction needs . This is a fundamental point to remember, since when this clever gland slows your metabolic rate down or ramps it up, you can and should investigate what it is that is prompting it to do so.
If you have read so far, I do need you to stay with me as I try to explain how the thyroid functions, from a physiological and biochemical standpoint, in the simplest way I can. Understanding how this powerful gland works will give you an advantage when confronted with the possibility that your doctor may not be paying attention, or dismissing your symptoms as stress or age-related.
The thyroid is a small gland (about the size of an almond) located at the front base of your neck, and it operates as follows:
Thyroid function is spurred by hormone output from two glands in the brain, the hypothalamus and the pituitary, which work together to provide initial signaling - i.e. the chemical cue to ignite action, meaning to produce hormones. The hypothalamus sends TRH, thyrotropin-releasing hormone, to the pituitary gland, and the pituitary, in turn, sends a prompt to the thyroid in the form of another chemical signal called TSH, thyroid stimulating hormone. Once nudged by the pituitary, the thyroid releases hormones that reach all tissues in the body, regulating: cellular metabolism; the speed at which foods move through the GI tract; body temperature; immune responses; heart function; cognitive abilities; cholesterol production; menstrual cycles and ovulation; breathing rate; bone health; muscle function; stress and adaptive responses; skin and hair health; ultimately, body composition and weight.
The thyroid directly releases the following hormones [note: the indispensable building block for thyroid hormones is the iodine we get from the foods we ingest]:
T4 (Thyroxine) which is virtually biologically inactive; it can be thought of as a reservoir of thyroid hormone. It is called T4 because it is synthesized from a protein called thyroglobulin, residues of the amino-acid tyrosine, plus 4 atoms of iodine; for T4 to become active though, it must undergo a conversion to T3, during which an iodine atom is cleaved off. This conversion takes place in numerous tissues around the body, but primarily in the liver. Note: levels of T4 provide a feedback system for the pituitary to regulate production of TSH - i.e., when there is enough T4, the pituitary gets ‘told’ to temporarily stop sending TSH.
T3 (Triiodothyronine) is the active form of thyroid hormone, in fact it is 200 to 300 times more active than T4. It is the one that goes out and gets the jobs done around the body, the doer. As the name suggests, it has 3 Iodine molecules, but its basic chemical structure is the same as T4. Note: the thyroid only produces about 9 to 20 percent of T3, as opposed to the 80+ percent of T4.
T2 (3,5-Diiodothyronine) has recently been garnering more scientific attention for its role in metabolic health, more specifically in fatty acid oxidation, mitochondrial function and BMR, our basal metabolic rate, which it influences by increasing oxygen consumption. Note: T2 is necessary for production of an enzyme called deiodinase, that helps convert T4 into T3.
T1 (Monoiodotyrosine). Its physiological role was still being evaluated until very recently when it was found that T1 has an influence on the electrical input and charge of the brain and various mental disorders, including multiple sclerosis and Lou Gehrig’s syndrome, which can be a result of not enough T1 to recharge the brain. Note: you will not encounter this particular thyroid hormone in future discussions, as its role in metabolism is not yet well understood.
Calcitonin. As the name suggests, its role in the body is to use calcium for bone tissue formation. This mechanism of action keeps the calcium from depositing itself in soft tissue, which could cause damages, particularly to the heart. Interestingly, calcitonin ramps up production of osteoblasts, bone-forming cells, when blood calcium levels rise above 10.3mg/dl. This hormone gets secreted on a feedback system, when the thyroid detects too much calcium in the blood.
You must insist on getting the right lab markers tested
If you take into consideration everything I have written above about all the factors that come into play when it comes to thyroid function, and what TSH really is, you can easily begin to understand why testing TSH alone, or even the added T4, which is what some physicians now do, cannot possibly be enough to get to the root of health issues that are indicative of a compromised cellular metabolism. Let’s say those markers are fine by all conventional metrics, but you are still not feeling well because you are not efficiently converting T4 to T3, how would you know that just by testing TSH and T4? How would you know if perhaps the thyroid is simply hitting the brakes on your metabolic rate because, if it didn’t, disease-causing pathogens would thrive along with healthy cells? And how will you know what specific course of action is best to take in terms of nutrition and lifestyle, if testing doesn’t help you uncover the causes behind dysfunction?
Following is a list of all the key thyroid lab markers you should be proactive about getting tested, a brief explanation of what they are, and their updated (functional) reference ranges:
TSH, or Thyroid Stimulating Hormone, is actually the pituitary gland hormone that prompts the thyroid to release T4 and T3, as previously detailed. In hypothyroid states, where thyroid fitness is below proficient, TSH is typically high because of insufficient T4 - the pituitary senses the low levels of T4 and attempts to compensate by firing out more TSH (conversely, low TSH is typically a marker for hyperthyroidism). However, TSH could fluctuate irrespective of T4 values, due to several factors, e.g. blood pressure medications, diabetes and diabetes drugs, or issues with the pituitary gland. Aging can also affect TSH levels independently. This marker can only be thought of as a starting point, not an end-all and be-all determinant. More markers are needed to make a comprehensive evaluation of thyroid health, as explained ahead.
Conventional range: uIU/ml 0.4 - 4.5
Functional range: iIU/ml 0.5 - 2.0
Ft4, or Free T4. ‘Free’ indicates that the hormone is not bound to a carrier protein called TBG, or Thyroxine-Binding Globulin, one of the proteins that shuttle thyroid hormones around the body (think of it as a vessel that safely ferries them around the bloodstream). Free T4 is more important than T4, as it is able to dock onto tissue cell receptors freely, because it got off that vessel, and convert to T3.
Conventional range: ng/dl 0.8 - 1.8
Functional range: ng/dl 1.4 - 1.77. Values in the upper 30% of the range are considered optimal.
Total T4 tests a combination of both the TGB-bound (carrier protein-attached) form of the hormone and the free form. This test, without the added Ft4, can be misleading, since T4 values can be skewed by transport protein quantities. It is possible for an increase in TGB values to obscure a reduction of T4, leaving hypothyroidism undetected. High estrogen levels, oral contraceptives, pregnancy, diabetes and other diseases are common causes of increased TGB, which can cause T4 values to show up higher than they really are. Keep this in mind if your tests came back with only T4 added to TSH.
Conventional range:
Functional range: ug/d 6-12
Ft3, or Free T3, which also indicates the hormone is not bound to any carrier protein. This is by far the one lab marker that is most important in determining how well the thyroid is functioning, including how efficiently it is converting inert T4 to dynamic T3. The only drawback is that reduction of T3 may be tardy in hypothyroidism, meaning it might show up later than low FT4 and high TSH. This is why re-testing, when symptoms persist, is key.
Conventional range: ng/dl 2.0 - 4.4
Functional range: ng/dl 3.8 - 4.4 . Values in the upper 30% of the range are considered functionally optimal.
Total T3, which combines TGB-bound and unbound quantities of the T3 hormone present in the body.
Conventional range: ng/dl 76 - 181
Functional range: 150 - 180.
Rt3, or Reverse T3, basically an inert form of T3. Rt3 is the product of a retrograde conversion of T4, which happens during times of extreme stress, chronic inflammation, and even over-exercising: there is a newly investigated condition, which has been named ‘cell danger response’, that impairs proper conversion and utilization of active thyroid hormone. As I mentioned earlier, the thyroid will prioritize survival over metabolic processes that can go on the back burner, like hair and nail growth, sexual arousal, etc, and allocate energy to primary life-preserving functions. Doctors don’t like to run this lab, which is unfortunate since it indicates the presence of hindering factors that are dampening T4 to T3 conversion, and, if you are already on thyroid medication, a glimpse into whether that medication is right for you. This test is also particularly useful if you are trying to conceive, as it will flag possible setbacks: the thyroid holds sway over the reproductive system, and will shut down energy supply to it if it senses that fetus development may not be carried out or a pregnancy could be high risk.
Conventional range: ng/dl 9.2 - 24.1
Functional range: <15
TPO, Thyroid Peroxidase antibodies and TgAb, Thyroglobulin antibodies. Functional thyroid experts make it very clear these should both be checked, not just one of them, as it often happens. Thyroid Peroxidase and Thyroglobulin are proteins that are involved in the synthesis and conversion of thyroid hormones. These are the lab markers that are used to diagnose Hashimoto thyroiditis, an autoimmune condition in which the immune system progressively attacks and destroys healthy thyroid tissues. It is important to note that hypothyroidism is a causal syndrome, meaning it can have different underlying causes, and it is not synonym with Hashimoto disease, which is one of its causes. Early detection of these antibodies can dramatically impact how well Hashimoto is managed at the outset, before it progresses to the point of no return. Way too many medical doctors don’t run these labs when patients complain about symptoms, either because Hashimoto is not on their radar, or on the notion that there is no treatment for autoimmune conditions - however it is a fact that beginning to manage Hashimoto at inception can make a huge difference in terms of a possible remission. Also, if the test results do show numbers associated with Hashimoto, retesting as needed is extremely important, as many diet and lifestyle factors that trigger fluctuations in antibody levels can be corrected. Common triggers to antibody increases are high stress hormones, insulin resistance from a diet high in refined carbohydrates, chronic inflammation from processed foods and inflammatory fats. As well, autoimmune comorbidity is rather common (one condition triggers the other), and Hashimoto antibodies will increase, for instance, if a person develops Celiac disease or Epstein Barr. A sedentary lifestyle is also a major derailing factor when trying to keep Hashimoto’s progression at bay. You should, however, only insist on getting these markers checked if you have health complaints strongly suggestive of a thyroid dysfunction, no need to ask for them in a routine checkup setting if you are generally healthy and fit.
Reference ranges for antibodies are anywhere >0, depending on the labs used. The higher your values, the more advanced the stage of autoimmune disease.
You might likely be told that a TPO range between 35 and 500 signals a moderate risk for Hashimoto, however your symptoms are a reliable measure to cross-reference with lab values, since you may be feeling awful at 35 or pretty good at 200. TgAb levels over 9 IU/mL are said to indicate risk of progression to Hashimoto. However, not everyone with higher TgAb will develop the condition. Research also suggests TgAb levels above 40 IU/mL may be associated with an increased risk of thyroid cancer. Conventional medicine tends to discount low values as ‘not worrisome’, however in functional medicine, presence of antibodies at any level is taken seriously and kept in check.
T3UPT or T3 uptake, also known as T3 resin uptake test, tells us how much more hormone the carrier protein, TGB, can take on to carry out to cells. I like to think of it as ‘how many seats are left on the ferry that shuttles hormones around the bloodstream’. If T3UPT is low, seating is limited. which could, for instance, indicate that your thyroid medication dose is excessive, and if it’s high it might indicate a need to up the dose, to fill those seats. It can also be useful in cases of TGB imbalances. T3UPT is basically an indirect measure of T4, which is why it is only useful if tested alongside T4. This is not necessarily an essential test to take, but may add another layer to the clinical picture when needed.
Range: 28 to 38%
Ferritin test, urine hormone and metabolite panels, toxin and heavy metal screening, GI Map (gut health assessment), mineral analysis and nutrient deficiency tests, seemingly unrelated to the thyroid, are also used to check for factors that exert major influence on its functionality. I will discuss those separately, as management of concomitant hormonal and metabolic conditions may make all the difference in optimizing thyroid function.
{Please note: these statements are true for generally manageable states of thyroid health, however, serious medical conditions such as cancer or nodules may be present, which would require more invasive diagnostic testing such as ultrasound, radioiodine scan, CT, MRI and ultimately a biopsy. Further distinctions can be made among primary, secondary, congenital, neonatal, juvenile types of hypothyroidism. Only a specialized medical professional can make those distinctions and decide on a course of action.}