The thyroid is a butterfly shaped gland located at the front of the neck, wrapping around the windpipe. It consists of two lobes connected by a thin bridge of tissue called the isthmus. The thyroid is part of the endocrine system and plays a central role in regulating metabolism throughout the body.
The thyroid produces hormones that influence growth, brain development, digestion, bone maintenance, and overall metabolic activity. Its primary function is to help keep the body’s metabolic rate at an appropriate level so cells can produce and use energy efficiently.
The thyroid releases two main hormones:
• Thyroxine (T4)
• Triiodothyronine (T3)
T4 is produced in larger amounts and serves mainly as a precursor hormone, while T3 is the more biologically active form that exerts effects at the cellular level. In addition to T3 and T4, the thyroid also produces calcitonin, a hormone involved in calcium balance and bone metabolism.
Thyroid function is regulated by the brain through a tightly controlled feedback system involving the hypothalamus and the pituitary gland. When the body senses a need for more thyroid hormone, the hypothalamus releases thyrotropin releasing hormone (TRH). TRH stimulates the anterior pituitary gland to secrete thyroid stimulating hormone (TSH). TSH then signals the thyroid gland to produce and release T4 and T3.
This process operates through a negative feedback loop. When circulating levels of T4 and T3 are sufficient or high, they signal the hypothalamus and pituitary to reduce TRH and TSH release. When thyroid hormone levels are low, TSH rises to stimulate increased hormone production. This feedback loop helps maintain stable thyroid hormone levels in the body.
Proper thyroid function is essential for maintaining normal energy levels, mood, weight regulation, heart rate, and temperature control in adults. Even subtle disruptions in this system can influence how the body feels and functions over time.
Hypothyroidism
Hypothyroidism occurs when the thyroid gland does not produce enough thyroid hormones, primarily T4 and T3. In response, the anterior pituitary gland increases production of thyroid stimulating hormone (TSH) in an attempt to stimulate the thyroid to produce more hormones. Elevated TSH in this context is a compensatory response, not the cause itself.
Low thyroid hormone levels slow metabolic processes throughout the body, which leads to a wide range of symptoms that can develop gradually over time.
• Weight gain not explained by diet or activity
• Constipation
• Persistent fatigue or low energy
• Depressive or low mood symptoms
• Cold intolerance
• Brain fog or slowed thinking
• Dry, coarse skin
• Memory difficulties
• Slow heart rate
• Heavier or prolonged menstrual cycles
• Delayed deep tendon reflexes
• Puffy face or facial swelling
• Hoarse or deepened voice
Hashimoto’s Thyroiditis
Hashimoto’s thyroiditis is a chronic autoimmune condition in which the immune system mistakenly attacks the thyroid gland. This ongoing immune mediated inflammation gradually damages thyroid tissue and often leads to hypothyroidism over time.
It is commonly associated with elevated thyroid antibodies, particularly anti thyroid peroxidase (anti TPO) and anti thyroglobulin antibodies, which help confirm the autoimmune nature of the condition. Thyroid hormone levels may be normal in the early stages, but as glandular damage progresses, hormone production often declines.
Symptoms can develop slowly and may precede abnormal thyroid hormone levels, which is why antibody testing can be clinically useful in certain individuals.
Subacute Thyroiditis
Subacute thyroiditis is a self limited inflammatory condition of the thyroid that often occurs after a viral infection. It is also known as de Quervain thyroiditis, granulomatous thyroiditis, or giant cell thyroiditis, particularly in its classic painful form.
This condition typically follows a predictable course with three phases:
Thyrotoxic phase:
Inflammation causes stored thyroid hormones to leak into the bloodstream, leading to temporary hyperthyroid symptoms such as palpitations, heat intolerance, tremor, and anxiety.
Hypothyroid phase:
As hormone stores are depleted and the inflamed gland struggles to produce new hormone, thyroid levels drop. Symptoms may include fatigue, weight gain, and cold intolerance.
Recovery phase:
In most individuals, thyroid function gradually returns to normal, a state known as euthyroidism. Full recovery can take weeks to months.
Unlike autoimmune thyroid disease, antibody levels are usually low or absent in subacute thyroiditis
Hyperthyroidism
Hyperthyroidism occurs when the thyroid gland produces excessive amounts of thyroid hormones, T4 and T3. As thyroid hormone levels rise, the anterior pituitary gland responds by reducing its secretion of thyroid stimulating hormone (TSH). In this case, low TSH is a result of excessive thyroid hormone production, not the cause.
Elevated thyroid hormone levels accelerate metabolic processes throughout the body, which can affect nearly every organ system.
Common symptoms of hyperthyroidism may include:
• Palpitations or rapid heartbeat
• Unintentional weight loss despite normal or increased appetite
• Frequent bowel movements or diarrhea
• Heat intolerance and excessive sweating
• Anxiety or nervousness
• Irritability or mood changes
• Fine tremors, especially in the hands
• Muscle weakness, particularly in the upper arms and thighs
• Thinning or fragile skin
• Neck swelling or enlargement of the thyroid gland, also called a goiter
In Graves’ disease, an autoimmune cause of hyperthyroidism, additional features may include eye involvement such as bulging eyes, eye dryness, or pressure behind the eyes.
Graves’ Disease
Graves’ disease is an autoimmune disorder and the most common cause of hyperthyroidism. In this condition, the immune system produces antibodies that stimulate the thyroid gland to overproduce thyroid hormones.
Although Graves’ disease and Hashimoto’s thyroiditis are both autoimmune conditions, they affect thyroid function in opposite ways. Graves’ leads to excessive hormone production, while Hashimoto’s leads to reduced hormone production over time.
Eye involvement, known as Graves’ ophthalmopathy, occurs in up to 30 percent of individuals. Symptoms may include bulging eyes, redness, dryness, pressure, or visual changes caused by inflammation of the tissues around the eyes.
When Testing Makes Sense and Why Early Signs Matter
Thyroid testing is not recommended as a routine screening tool for everyone. Most clinical guidelines advise testing only when there are symptoms or known risk factors. That said, understanding when testing is appropriate and how early thyroid changes can show up is an important part of proactive health care.
Case Report:
J.D. is in her 30s and presents with elevated TSH levels. Her primary symptom is hair loss, along with fatigue, and cold intolerance. This is a good example of when thyroid testing is appropriate, as her laboratory results and symptoms together suggest a hypothyroid pattern.
Checking free T4, and in some cases free T3, alongside TSH helps clarify whether the dysfunction originates at the thyroid gland itself (primary hypothyroidism) or higher up in the regulatory pathway involving the pituitary or hypothalamus (secondary or central hypothyroidism).
Relying on TSH alone can miss certain clinical scenarios. Central hypothyroidism may present with normal or low TSH despite low thyroid hormone levels. In other cases, individuals may have adequate T4 levels but impaired conversion to T3, the active hormone. Measuring free T4 and, when clinically indicated, free T3 provides a more complete picture of thyroid hormone availability at the tissue level.
Does This Change the Treatment Plan?
Yes, in several important ways.
In primary hypothyroidism, the standard treatment is levothyroxine, a synthetic form of T4. Dosing is typically adjusted based on TSH levels in combination with symptoms.
In secondary (central) hypothyroidism, levothyroxine is still commonly used, but TSH cannot be relied upon for monitoring. Instead, treatment is guided by free T4 levels and clinical response, with free T3 sometimes considered as supportive information.
Understanding T3 physiology is also important. T3 is the biologically active thyroid hormone. Unlike T4, which primarily serves as a circulating reservoir, T3 enters cells directly, regulates gene expression, and drives many metabolic functions. Medications such as Synthroid provide T4 only and depend on the body’s ability to convert T4 into T3.
When conversion from T4 to T3 is inefficient, supporting the physiologic process becomes clinically relevant. Micronutrients such as selenium and zinc play a role in thyroid hormone metabolism and may be considered as part of a broader, individualized care plan, alongside medical therapy when appropriate.
This patient was treated with desiccated thyroid, a natural thyroid hormone preparation derived from dried porcine thyroid glands. Desiccated thyroid contains a combination of both T4 (thyroxine) and T3 (triiodothyronine), unlike synthetic levothyroxine, which provides T4 alone.
Because desiccated thyroid includes T3, it may be considered in selected patients who continue to experience symptoms despite adequate T4 therapy or who have difficulty converting T4 into T3. The T3 component is biologically active and acts more quickly at the cellular level, which some patients report as improved symptom relief. It is important to note that the T4 to T3 ratio in porcine thyroid differs from that of the human thyroid, which is why careful dosing and monitoring are essential.
Compounding pharmacies can prepare desiccated thyroid in customized capsule strengths, allowing for individualized starting doses and incremental adjustments based on laboratory values and clinical response. This can be particularly useful when patients require doses that are not commercially available.
At a three month follow up, TSH, free T4, and thyroid antibodies such as anti TPO were reassessed. Improvements in laboratory markers were accompanied by a reduction in symptoms, supporting the importance of individualized therapy and ongoing monitoring rather than relying on a single lab value alone.
As with all thyroid treatments, desiccated thyroid is not appropriate for every patient, and therapy should be guided by a knowledgeable healthcare provider with regular follow up to ensure safety and effectiveness.
When Thyroid Testing Is Typically Recommended
Conventional medical guidelines suggest thyroid testing for individuals who have symptoms or belong to higher risk groups, rather than testing asymptomatic adults. Common reasons to consider testing include:
• Persistent fatigue
• Unexplained weight changes
• Heat or cold intolerance
• Hair thinning or hair loss
• Changes in heart rate
• Mood changes or brain fog
Testing is also commonly recommended in people with higher risk factors, including:
• Pregnancy or postpartum period
• Personal or family history of autoimmune disease
• First degree relatives with thyroid disease
• Use of medications that affect thyroid function
• History of head or neck radiation
These recommendations aim to balance early detection with avoiding unnecessary testing in people unlikely to benefit.
Lab Ranges vs Functional and Naturopathic Ranges
Standard laboratory reference ranges are statistically derived. They are designed to include approximately 95% of the population, not necessarily to define an optimal or symptom free range.
Naturopathic and functional medicine practitioners often use narrower, physiologic ranges. These are based on observational data showing that individuals with thyroid values at the edges of the lab “normal” range may have:
• Higher thyroid antibody levels
• Greater likelihood of progressing to subclinical hypothyroidism
• Increased risk of developing autoimmune thyroid disease
Research also shows that having a first degree relative with autoimmune thyroid disease increases personal risk by approximately ninefold compared to the general population (PMID: 28273382). Furthermore, broader ranges may miss subclinical hypothyroidism linked to symptoms like fatigue.
Because of this, some clinicians view borderline lab results as an early risk signal rather than a definitive diagnosis, especially when symptoms or antibodies are present. This approach is not meant to replace conventional diagnosis but to identify patterns that may warrant closer monitoring.
Nutritional and Herbal Support for Thyroid Health
Natural and nutritional strategies are often used as supportive care alongside medical guidance. These do not replace prescription therapy when it is indicated.
Selenium
The thyroid contains the highest concentration of selenium per gram of tissue of any organ. Selenium plays a key role in thyroid hormone metabolism and antioxidant protection.
Evidence suggests selenium supplementation may:
• Reduce anti TPO antibody levels in Hashimoto’s thyroiditis
• Improve thyroid ultrasound appearance
• Modestly lower TSH in some individuals not on hormone replacement
In Graves’ disease, selenium used alongside antithyroid medication has been shown to:
• Normalize thyroid stimulating antibodies more quickly
• Reduce free T4 and free T3 levels
• Improve mild thyroid eye symptoms and quality of life
Iodine
Iodine is essential for thyroid hormone production, but both deficiency and excess can be problematic.
Iodide enters thyroid cells through the sodium iodide symporter and is transported into the follicle where thyroid peroxidase converts it into an active form. This process allows iodine to bind to tyrosine residues on thyroglobulin, forming the building blocks of thyroid hormones.
Adequate intake supports hormone synthesis, but excessive iodine may worsen autoimmune thyroid conditions in susceptible individuals.
Guggul
Guggul is a resin from the Commiphora mukul tree used in Ayurvedic medicine. Preliminary animal and early human data suggest it may:
• Support conversion of T4 to the active T3 hormone
• Help normalize TSH in hypothyroid models
• Improve lipid metabolism and antioxidant activity
Human evidence is limited, so it should be considered supportive rather than therapeutic.
Ashwagandha
Ashwagandha may support thyroid health indirectly by:
• Modulating the stress response via the HPA axis
• Reducing cortisol related suppression of thyroid function
• Providing antioxidant protection to thyroid tissue
It may be most helpful in individuals with stress related symptoms rather than overt thyroid disease.
Nutrition and Thyroid Considerations
Certain foods can support thyroid health, while others may need moderation depending on thyroid status.
Brazil nuts are a rich natural source of selenium and can contribute to overall thyroid support when consumed in small amounts.
For individuals with hyperthyroidism, excess iodine intake may worsen symptoms. Foods to be mindful of include seaweed, iodized salt, dairy products, egg yolks, shellfish, soy products, and high caffeine intake.
For hypothyroidism, some foods can interfere with medication absorption or exacerbate symptoms when consumed in excess. These include:
• Soy products
• Very high fiber diets
• Large amounts of raw cruciferous vegetables
• Highly processed, high sodium foods
• Sugary and fried foods
• Coffee or alcohol taken close to thyroid medication dosing
Timing and moderation matter more than complete avoidance in most cases.
A Thoughtful Approach to Thyroid Care
This information is not intended to encourage routine thyroid testing in everyone. Instead, it highlights the importance of recognizing early signs, understanding personal risk factors, and supporting thyroid health through evidence informed lifestyle and nutritional choices.
If you have symptoms, a family history, or concerns about thyroid health, speak with your healthcare provider to determine whether testing or monitoring is appropriate for you.
Education and awareness are often the first steps toward prevention and long term health. This blog is only for education purpose.
References:
Huwiler, V. V., Maissen-Abgottspon, S., Stanga, Z., Mühlebach, S., Trepp, R., Bally, L., & Bano, A. (2024). Selenium Supplementation in Patients with Hashimoto Thyroiditis: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. Thyroid : official journal of the American Thyroid Association, 34(3), 295–313. https://doi.org/10.1089/thy.2023.0556
Meamar, R., Feizi, A., Aminorroaya, A., Amini, M., Nasri, M., Tabatabaei, A., & Abyar, M. (2021). A Thyroid Stimulating Hormone Reference Range: Iranian Thyroid Cohort study. Acta bio-medica : Atenei Parmensis, 92(5), e2021283. https://doi.org/10.23750/abm.v92i5.9643
Ventura, M., Melo, M., & Carrilho, F. (2017). Selenium and Thyroid Disease: From Pathophysiology to Treatment. International journal of endocrinology, 2017, 1297658. https://doi.org/10.1155/2017/1297658
About the author:
Hi, I’m Abinaa, a fourth-year naturopathic medical student at the Canadian College of Naturopathic Medicine with a deep-rooted passion for natural healing, inspired by my South Asian upbringing. Through this blog, I hope to share my journey, explore topics in holistic health and wellness, and offer simple, thoughtful insights that support a more balanced and mindful way of living.
