Thyroid Health: Your Complete Functional Medicine Guide To Supplements, Diet & More

Thyroid Health: Your Complete Functional Medicine Guide To Supplements, Diet &Amp;Amp; More Dr. Will Cole

There is no other hormone that plays a bigger role in your overall health than your thyroid. In fact, your thyroid affects every single area of your health including your brain, gut, and overall hormone function. With that being said, thyroid issues are one of the most common health problems I see in my telehealth functional medicine clinic.`

While conventional medicine tends to look at thyroid problems as something that you will have to deal with for the rest of your life, functional medicine takes a different approach. Instead of looking at thyroid problems as a daily struggle, we believe there is hope to achieve remission from symptoms and long-term, sustainable healing. So let’s take a closer look at how we can facilitate this healing naturally, through supplements, diet, and lifestyle.


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Natural vs. traditional treatments

Treatment for thyroid problems varies drastically between functional and conventional medicine, starting with the labs they use to measure your thyroid health. In conventional medicine, the reference range is based on a bell curve - a statistical average of the population of that particular lab that you went to. 

Who goes to labs? Sick people. That’s why if your labs come back within the normal reference range, it doesn’t mean it’s optimal. So while your conventional doctor might say your results are in a “normal” range, a functional medicine doctor is able to see sooner whether you are trending toward dysfunction because they look at a narrower reference range. 

Here’s what a functional medicine thyroid panel should look like and the appropriate reference ranges:


  • Lab range: .45-5.5 mlU/L
  • Optimal range: 1.8-2.5 mlU/L

Total T4

  • Lab range: 4.5-12 mcg/DL
  • Optimal range: 6.0-12.0 mcg/DL

T3 Uptake

  • Reference range: 22-35%
  • Optimal range: 28-38%

Total T3

  • Lab range: 80-200 ng/DL
  • Optimal range: 100-180 ng/DL

Free T4

  • Lab range: 0.8-1.8 ng/DL
  • Optimal range: 1.0-1.5 ng/DL

Free T3

  • Lab range: 2.3-4.2 pg/mL
  • Optimal range: 3.0-4.0 pg/mL

Reverse T3

  • Reference range: 8-25 ng/DL
  • Optimal range: 9.2-24.1 ng/DL

Thyroid Antibodies

  • Thyroid Peroxidase (TPO) Ab optimal range: 0-15 IU/mL
  • Thyroglobulin Ab optimal range: 0-0.9 IU/mL

In addition to a more expanded thyroid panel, functional medicine also runs more diagnostic testing to look for dysfunction in other areas of the body that can contribute to thyroid problems such as your gut and brain.

The other thing that differs between functional and conventional medicine, is the treatment itself for thyroid problems. In conventional medicine the first and only treatment option is medication. Typically, you would be prescribed a thyroid replacement hormone like one of the following:

  • Levothyroxine: A synthetic T4 hormone that is branded under 30 different names including Synthroid and Levothroid
  • Liothyronine: A synthetic form of T3, the active form of your thyroid hormone

On occasion, your doctor might prescribe you a natural thyroid supplement. These are derived from pig thyroid tissue and contain both T4 and T3 hormones. The most common brands include Armor, Nature-throid, and Westhroid.

The problem with medication though, is that it is generally prescribed regardless of your underlying thyroid issue. Instead of addressing the root cause of why you have thyroid problems in the first place, medication just acts as a bandaid for your symptoms instead of facilitating true healing.

On the other hand, functional medicine takes a whole-body approach to treating thyroid problems. That isn’t to say that thyroid medication might not be necessary for some individuals for a period of time, but we understand that no one is sick from a medication deficiency. Instead, we aim to find the underlying reasons why your thyroid isn’t functioning properly and address symptoms naturally through diet and lifestyle changes - thus, alleviating your symptoms and mitigating the need for medication.

With that being said, what improves thyroid function? Ultimately, that comes down to the individual. Once your functional medicine practitioner knows what is hindering your thyroid health, they can come up with the best course of action for your specific health case. However, there are a few supplements and wellness tools that have been studied for their ability to improve thyroid function.

Best thyroid support supplements

While you are healing, supplements are a great way to support your thyroid health. So what, supplements are good for the thyroid? Here are some of my favorite thyroid support supplements for overall healthy hormones. Just remember, I always suggest working with a functional medicine practitioner who can give you more targeted recommendations based on your specific thyroid problem.

1. Iodine

You need iodine (1) to produce thyroid hormones however, deficiencies in this nutrient are common since your body doesn’t produce it on its own and most people don’t get enough through their diets. But here’s where bioindividuality comes into play. 

If you have hypothyroidism (low thyroid function) you can certainly benefit from iodine supplementation. However, too much iodine can have a detrimental effect on your health by increasing thyroid antibodies which can even contribute (2) to Hashimoto’s disease. A functional medicine doctor can run labs to determine your levels and whether or not an iodine supplement is right for you.

2. Zinc

This mineral is responsible (3) for aiding in the production of TSH, T4, and T3 hormones and helps convert T4 to T3. A zinc deficiency can lead to hypothyroidism and contribute to hair loss - one of the main symptoms of hypothyroidism.

3. Copper

Copper goes hand-in-hand with zinc, balancing each other out so that either one doesn’t get too high. More specifically, copper is needed to produce (4) T4 hormones and regulates how much is absorbed into your cells. While supplementation can help with extreme deficiencies, I prefer to use food as your main source for copper and zinc and focus on supplementation for these other nutrients. 

4. Iron

Since your body doesn’t produce iron naturally, you have to get it through food. Deficiencies in this nutrient are extremely common, especially among women (who also happen to have higher rates of thyroid problems compared to men). Iron works to convert T4 to the active form of thyroid hormone, T3 with deficiencies linked (5) to the development of hypothyroidism.

5. Vitamin D

Most people are deficient in vitamin D. Other than your thyroid hormone itself, it is the only nutrient used by every single cell of your body. Your thyroid also relies on it to help lower (6) elevated TSH levels. 

It can be difficult to get enough vitamin D through food alone so supplementation is usually needed. Based on where your starting level is, I typically suggest supplementing with anywhere between 2,000 and 6,000 IU of vitamin D each day. 

6. Vitamin C

Some research has linked (7) vitamin C supplementation to reduced Hashimoto's symptoms.

Possible underlying health issues

Since your thyroid impacts your entire health, it only makes sense that thyroid problems can be triggered by a variety of different factors. Identifying the particular cause behind your thyroid problem can help you zero in on the best tools, supplements, and diet to help overcome your thyroid problem.

1. Stress

Chronic stress has been linked (8) to the onset of thyroid problems due to the fact that cortisol can affect the conversion of T4 to active T3 while also increasing the unnecessary reverse T3 hormone. This can wreak havoc on your thyroid hormone levels and lead to an imbalance in all types.

2. Nutrient deficiencies

As we’ve seen, your thyroid hormones are fueled by certain amounts of specific nutrients. Deficiencies in selenium, (9) vitamin A, (10) and vitamin D are all linked to autoimmune thyroid conditions.

3. Gut problems

Approximately 20 percent of your T4 is converted to T3 in the gut, and an imbalanced, unhealthy microbiome can inhibit this process.

4. Toxin exposure

We are constantly exposed to toxins in our food, personal care products, and even the air we breathe. Unfortunately, this onslaught of toxins can take a toll on your thyroid hormones with studies showing that heavy metals can lead to an autoimmune response (11) against your thyroid.

5. Hormone imbalances

As the chemical messengers of your body, hormones direct every system in your body to function properly. Since your hormones are all connected, if there is dysfunction in one area it results in dysfunction in the rest of your hormones. For example, low estrogen, (12) was found to inhibit thyroid function

Thyroid supplements to avoid

Are thyroid support supplements good? The answer depends on what you are taking. In general, yes. Supplements have been proven to help aid in proper thyroid function but there are also some supplements that you should avoid, mainly based on their quality.

When choosing what supplement to take, always be on the lookout for unnecessary, added ingredients that can further perpetuate thyroid problems. Also, pay attention to recommended dosages - too much of anything, even something beneficial, can cause problems with your health in the long-run. What works for one person might not work for you, so work with your doctor to narrow down a targeted list of supplements for your health case.

Best foods to support thyroid health

How can I boost my thyroid naturally? Well, as a functional medicine practitioner, I believe food is foundational when it comes to transforming your health. Unlike a single-nutrient supplement, foods contain multiple different nutrients in a single source! Dark leafy greens, eggs, nuts and seeds, wild-caught seafood, and avocados all contain high levels of the nutrients listed above. If you are really looking to up your thyroid healing game, load up on these next-level superfoods during your next grocery trip.

1. Sea vegetables

Our oceans are a vast resource of superfoods. Sea vegetables like dulse, kombu, nori, and kelp are all rich in iodine that is necessary for producing thyroid hormones. 

2. Brazil nuts

These nuts are high in selenium - an essential nutrient needed to convert T4 to T3. Without this conversion, your body will overproduce the unusable form of your thyroid hormone that can end up blocking thyroid function. Typically 2-4 Brazil nuts is all you need to meet your daily selenium requirements.

3. Wild-caught salmon

Fatty fish like salmon are rich in vitamin D to support your thyroid hormone receptor sites.

4. Organ meats

Organ meats have some of the highest levels of the iron that your body needs to convert T4 to the usable T3.

5. Oysters

Treat yourself to some oysters next time you are out for brunch because this superfood is packed with zinc and copper - two minerals needed for healthy thyroid hormones.

When to seek help from a medical professional?

Thyroid problems can have wide-ranging effects on your total health and can include symptoms like:

  • Brain fog
  • Low libido
  • Chronic fatigue
  • Hair thinning and loss
  • Brittle nails
  • Weight loss resistance
  • Trouble gaining weight

These health problems can impact your daily life and make it difficult to make it through your day. If you suspect that you have a thyroid problem or notice any of these symptoms, it’s important to seek out a medical professional who can confirm any underlying thyroid problems and guide you through your healing journey.

In my telehealth functional medicine clinic, we run extensive labs that look at everything from your thyroid levels to your gut microbiome function in order to put together a plan of care that addresses your particular needs. We also take into consideration your entire health case - lifestyle factors, past trauma, diet, stressors, and more - that can impact your physical health and thyroid levels. By taking a comprehensive look at your health, functional medicine aims to put thyroid problems into remission naturally, for long-term, sustainable healing.

If you want to get to the root of your thyroid problems, schedule a telehealth consultation to learn more about how we can help you with functional medicine.

As one of the first functional medicine telehealth clinics in the world, we provide webcam health consultations for people around the globe.


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  1. Chung, Hye Rim. “Iodine and thyroid function.” Annals of pediatric endocrinology & metabolism vol. 19,1 (2014): 8-12. doi:10.6065/apem.2014.19.1.8
  2. Leung, Angela M, and Lewis E Braverman. “Consequences of excess iodine.” Nature reviews. Endocrinology vol. 10,3 (2014): 136-42. doi:10.1038/nrendo.2013.251
  3. Severo, Juliana Soares et al. “The Role of Zinc in Thyroid Hormones Metabolism.” International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition vol. 89,1-2 (2019): 80-88. doi:10.1024/0300-9831/a000262
  4. Manisha, Arora, Roshan Kumar Mahat, Sudeep Kumar, et. al. "Study of Trace Elements in Patients of Hypothyroidism with Special Reference to Zinc and Copper" BioMedical Journal of Scientific & Technical Research July 2018. doi: 10.26717/BJSTR.2018.06.001336
  5. Soliman, Ashraf T et al. “Chronic anemia and thyroid function.” Acta bio-medica : Atenei Parmensis vol. 88,1 119-127. 28 Apr. 2017, doi:10.23750/abm.v88i1.6048
  6. Talaei, Afsaneh et al. “The Effects of Vitamin D Supplementation on Thyroid Function in Hypothyroid Patients: A Randomized, Double-blind, Placebo-controlled Trial.” Indian journal of endocrinology and metabolism vol. 22,5 (2018): 584-588. doi:10.4103/ijem.IJEM_603_17
  7. Karimi, F, and G R Omrani. “Effects of selenium and vitamin C on the serum level of antithyroid peroxidase antibody in patients with autoimmune thyroiditis.” Journal of endocrinological investigation vol. 42,4 (2019): 481-487. doi:10.1007/s40618-018-0944-7
  8. Matos-Santos, A., Nobre, E.L., Costa, J.G.E., Nogueira, P.J., Macedo, A., Galvão-Teles, A. and De Castro, J.J. (2001), Relationship between the number and impact of stressful life events and the onset of Graves' disease and toxic nodular goitre. Clinical Endocrinology, 55: 15-19.
  9. Roland Gärtner, Barbara C. H. Gasnier, Johannes W. Dietrich, Bjarne Krebs, Matthias W. A. Angstwurm, Selenium Supplementation in Patients with Autoimmune Thyroiditis Decreases Thyroid Peroxidase Antibodies Concentrations, The Journal of Clinical Endocrinology & Metabolism, Volume 87, Issue 4, 1 April 2002, Pages 1687–1691,
  10. Farhangi, Mahdieh Abbasalizad et al. “The effect of vitamin A supplementation on thyroid function in premenopausal women.” Journal of the American College of Nutrition vol. 31,4 (2012): 268-74. doi:10.1080/07315724.2012.10720431
  11. Langer, Pavel et al. “Fish from industrially polluted freshwater as the main source of organochlorinated pollutants and increased frequency of thyroid disorders and dysglycemia.” Chemosphere vol. 67,9 (2007): S379-85. doi:10.1016/j.chemosphere.2006.05.132
  12. Abdel-Dayem, M.M., Elgendy, M.S. Effects of chronic estradiol treatment on the thyroid gland structure and function of ovariectomized rats. BMC Res Notes 2, 173 (2009).

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The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.

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Dr. Will Cole, DNM, IFMCP, DC is a leading functional medicine expert who consults people around the globe, starting one of the first functional medicine telehealth centers in the world. Named one of the top 50 functional and integrative doctors in the nation, Dr. Will Cole provides a functional medicine approach for thyroid issues, autoimmune conditions, hormonal imbalances, digestive disorders, and brain problems. He is the host of the popular The Art Of Being Well podcast and the New York Times bestselling author of Intuitive Fasting, Ketotarian, The Inflammation Spectrum and the brand new book Gut Feelings: Healing the Shame-Fueled Relationship Between What You Eat and How You Feel.

Gut Feelings Dr. Will Cole 6

Gut Feelings

Healing The Shame-Fueled Relationship
Between What You Eat And How You Feel