10 thyroid secrets your doctor doesn't know about

Updated: Jun 30

By and large, I continue to see patients who've been told their thyroid function is normal and have only had their TSH tested! In this post I explain a bit about what your thyroid is, why it's so important that it functions well, and the best ways we have (to date) to find out if it's functioning optimally.


Also, if you've been diagnosed with low thyroid function, please make sure you get your thyroid antibodies checked. The most common cause of hypothyroidism is actually an autoimmune disease called Hashimoto's thyroiditis. More on this below.


The thyroid is a small gland located in the lower-front part of your neck. It's responsible for helping to regulate many of the body's critical processes, such as metabolism, energy generation, and mood. The hormones secreted by the thyroid have effects on almost every body tissue.

These include:

  • Metabolic. The thyroid hormones increase your basal metabolic rate. Appetite, the absorption of the food you eat, and gut movement are all influenced by the thyroid hormones. They increase absorption of glucose, or simple sugars in your gut, the uptake of glucose by your cells, and the breakdown of glucose by your liver. They stimulate the breakdown of fats, and increase the number of free fatty acids. Thyroid hormones also decrease cholesterol levels, perhaps by increasing the rate of secretion of cholesterol in the bile.

  • Cardiovascular. Thyroid hormones increase the rate and strength of the heartbeat. They increase the rate of breathing, intake and consumption of oxygen, and increase the activity of the mitochondria, or energy makers, in your cells. Combined, these factors increase blood flow and the body's temperature.

  • Developmental. Thyroid hormones are important for normal development. They increase the growth rate of young people, and the cells of the developing brain are a major target for the thyroid hormones T3 and T4. Thyroid hormones play a particularly crucial role in brain maturation during fetal development and first few years of postnatal life..

  • These hormones also play a role in maintaining normal sexual function, sleep, and thought patterns. Increased levels are associated with increased speed of thought generation but decreased focus. Sexual function, including libido and the maintenance of a normal menstrual cycle, are also influenced by thyroid hormones.


Secret 1: Low thyroid function (hypothyroidism) may not be noticed early on.

You may have no symptoms at all. Over time, untreated hypothyroidism can cause a number of health problems, such as obesity, joint pain, infertility and heart disease. If you're tired and have an increased sensitivity to cold, these may be the first symptoms of low thyroid hormones. If you're aging and you feel you no longer have that edge - please check your thyroid hormones levels. Other lesser known symptoms include: constipation, dry skin, weight gain, puffy face, a hoarse voice, muscle weakness and/or pain, stiffness or swelling in your joints. Low thyroid function can also cause high cholesterol levels, thinning hair or a slowed heart rate. For me, even a symptom such as depression is enough to test thyroid levels.



Secret 2: Lab reference ranges for TSH are changing.

TSH stands for thyroid stimulating hormone, and it's secreted by the pituitary gland. It's not a thyroid hormone at all - it gets released based on a negative feedback loop that involves detection and monitoring of the thyroid hormones by the hypothalamus. Most doctors only order TSH to check your thyroid function, in which case we don't know what's going on with your actual thyroid hormone levels or if your pituitary and hypothalamus are working well. (See Secret 3 to find out what to order).


Most lab reference ranges for TSH continue to be .5-4.5. These ranges are outdated. The optimal range for TSH is .3-2.0 as highlighted by the group of physicians who specialize in thyroid conditions, The American Association of Clinical Endocrinologists.



( American Assoc of Clinical Endos (AACE); Nov 2002)



Secret 3: Out with the Old Tests

In the past, thyroid values were evaluated through a combination of different tests. Serum CK values, radioactive iodine uptake, basal metabolic rate and eventually TSH. What's now known to be much more accurate is to test the actual levels of thyroid hormones, free T4 and free T3.


Here's my go-to list of what blood work to order when I'm seeing someone and we need to evaluate their thyroid function:

  • Total T4

  • Thyroxine free index; FT1, T7, FT4

  • rT3 uptake

  • TSH

  • Test free hormones fT3 & fT4

  • Thyroid Antibodies; TPO Ab, AntiTG

  • Ferritin, serum iron, TIBC (see Secret 6)


Secret 4: Always test for Antibodies

The thyroid antibodies we currently can test for include thyroid peroxidase antibodies (TPO Ab) and anti-thyroglobulin antibodies (AntiTG). The immune system, for a whole host of reasons, can be triggered to destroy thyroid peroxidase, an enzyme usually found in the thyroid that plays in important role in the production of thyroid hormones. When this happens, lots of T4 and T3 get released into the body, producing a thyroid storm. This injures the thyroid gland, and you will eventually become hypothyroid. Having a positive antibody test is a good predictor of thyroid disease.


Secret 5: Follow the Gut

The thyroid gland, during embryological development, comes from the same cells that make the gastrointestinal tract. Poor digestive health can translate to poor thyroid health. Anyone that I see with positive antibodies on their bloodwork (Secret 4) should also be screened for antibodies to gluten. In other words, there is a very high prevalence of gluten sensitivity in people with TPO or AntiTG antibodies. It's pretty much guaranteed that anyone with antibodies over 100 has a gluten sensitivity. So here, part of our treatment is eliminating gluten from the diet.


I also check for bugs. Coxsackie B, H pylori, E Coli, Yersinia, Mycoplasma, Lyme, and EBV can trigger an autoimmune issue or can be a part of the diagnosis of hypothyroidism. My goal is to always look for the root cause of what's affecting the thyroid.



Secret 6: Test ferritin levels

Ferritin is a storage form of iron. If ferritin is low, this can negatively affect thyroid health. Thyroid peroxidase, the enzyme that's involved in the production of thyroid hormones, is dependent on sufficient iron stores in the body. In other words, when checking your thyroid, check your iron values as well. Serum iron, TIBC, and ferritin. Optimal ferritin levels range between 50-100.



Secret 7: The thyroid is a canary

The thyroid is highly sensitive to environmental toxicity, heavy metals such as mercury, lead, and cadmium, perchlorate, PCBs, dioxins, and poly-brominated diphenyl ethers. Testing for these substances is difficult. Fat biopsies are an option, though they are very expensive unless your practitioner knows what she is looking for. Detoxification protocols are also an option - though frankly they are a pain in the butt. If you're considering heavy metal or environmental toxicity testing, make sure you see someone who knows what they are doing. These treatment protocols are time and money intensive.


Secret 8: The Holy Hormone Trinity

Thyroid hormones, cortisol levels and estrogen/reproductive hormones are all co-dependent and interrelated. It's essential to evaluate all parts of this triangle when understanding the root cause of your thyroid imbalance.


  • Cortisol slows everything down. For example, cortisol inhibits the conversion between T4 and T3, it also inhibits the function of TSH. If you have chronically elevated cortisol as a result of stress or pain, and you have thyroid disease, treating both issues will be essential to fully resolving the issue. Low cortisol levels can also mimic hypothyroidism and depression/anorexia are associated with hypothyroidism. I test anyone I see with low thyroid function for coinciding adrenal fatigue and I make sure I supplement with B Vitamins if indicated. You can check your adrenal function by testing salivary hormone levels.

  • Estrogen: It is essential to check and treat your thyroid before, during or after your pregnancy. Increased estrogen during pregnancy or postpartum can unmask thyroid problems. Severe nausea of pregnancy is associated with autoimmune thyroid issues. High TSH levels can reduce prolactin levels, the hormones needed to produce milk. Hypothyroidism can be a primary cause for post-partum depression (here it is crucial to check antibodies.

  • And there is a correlation between breast cancer and thyroid function!! People with PCOS may come in with skin problems and this will be the only sign of hypothyroidism. Guys will talk about losing their edge, not feeling as motivated in their work and will talk about depression. Please get your thyroid checked!


Secret 9: Take Selenium

(200mcg-800mcg daily)

Deficiencies in selenium are associated with functional hypothyroidism. There are broad areas of Canada and the United States where soils, and consequently plants grown on those soils, contain very low levels of selenium. In the United States the most selenium-deficient areas are the Northwest, Northeast, the Atlantic coastal area, Florida, and regions surrounding the Great Lakes.


Secret 10: Integrative treatments for the thyroid work best

All thyroid is bio-identical; Synthroid, Compounding, Armour, Westthroid

T4 + T3 in combination generally work much better clinically for folks who need thyroid supplementation. There are also combination supplements that supply selenium and thyroid glandulars. Phytolacca Oil is great to use topically for an inflamed thyroid. If you have antibodies to your thyroid tissue, all glandular supplements should be eliminated. You may be low in Magnesium and calcium with hypothyroidism.


Testing: Make sure to get all labs recommended above and retest every month until you get a good dosage with your thyroid supplementation. Thereafter you can monitor hormone levels every 6 months, and no longer than one year. Continue to self check your symptoms.


And make sure you have a really good physician who can review all of this with you to help you get to the root cause of your thyroid issues. Many thyroid imbalances can be reversed with the proper treatment.


Feel free to leave a comment or a question in the comment box below.

We're in this together,


Dr Kelly Jennings