1. Introduction
2. The Interconnected Web
2.1 The Role of Thyroid Hormones
2.2 The Hypothalamus-Pituitary-Thyroid-Adrenal (HPTA) Axis
2.3 Mood and Neurotransmitter Dysregulation
3. Lifestyle Components to Support Healthy Thyroid Function
4. Nutrient Solutions to Support Thyroid Function
5. Pure Encapsulations Nutrient Solutions
6. Conclusion
7. Resources

By: Kim Ross, DCN, CNS, LDN, IFMCP

Occasional stress and anxious feelings have implications for thyroid health. A poll conducted in 2024 by the American Psychiatric Association revealed that 43% of adults in the United States experience increased feelings of occasional anxiousness, with 53% of those polled attributing this feeling to stress.¹ The American Thyroid Association reports that approximately 12% of the U.S. population will experience changes in thyroid function at some point in their lives ², though the data on the prevalence varies from 4.6%-14.4%.³ Suboptimal thyroid function is characterized by compromised thyroid hormone production or conversion of thyroxine (T4) to triiodothyronine (T3). Thyroid antibodies may also be present, with or without changes in thyroid hormone levels, resulting in a self-tissue response. Low mood is a common symptom of changes in thyroid hormone levels, with 63% of adults with suboptimal thyroid function having some degree of anxious feelings.⁴

Conventional intervention approaches often focus on symptom management rather than addressing the root causes of stress, mood dysregulation and thyroid-related symptoms. For example, the most common medical intervention for thyroid support is the use of synthetic T4 medications, which may stabilize thyroid hormone levels but can exacerbate anxious feelings in some patients.⁵

Pharmaceuticals used for mood regulation have variable efficacy and carry risks that should be carefully considered.⁶ These limitations underscore the need for a nutrient-focused, integrative approach to supporting thyroid health, resilience and emotional balance.

It’s important to note that any recommendations are not meant to treat, cure, or prevent diseases or be a substitute for medical, diagnostic, and treatment options. Dietary supplements are not intended to replace the use of any medications prescribed.

It can be a challenge deciding optimal clinical recommendations when patients present with occasional stress, anxiousness and changes with thyroid function, with or without the presence of thyroid antibodies. It can be helpful to review the interconnected web between the three to help determine the appropriate and most optimal course of action.

The hypothalamus-pituitary-thyroid (HPT) axis is the neuroendocrine system that controls the production of thyroid hormones through a feedback loop. Thyroid stimulating hormone (TSH), is produced by the pituitary gland, which signals the thyroid gland to produce thyroid hormones, primarily thyroxine (T4). Once T4 is secreted, it is bound to transport proteins and carried to the cells and tissues where it passes through a series of metabolic transformations. It is then activated to triiodothyronine (T3) or inactivated into reverse T3 (rT3). This entire process is largely influenced by nutrient (in)sufficiency, stress and other lifestyle factors. However, loss of self-tolerance is another influential factor in this process. Thyroid antibodies may be present with or without abnormalities in the production of TSH, T4 and/or T3 and can contribute to a suboptimal thyroid. Genetics, cytokine dysregulation, diet and lifestyle factors are commonly noted as contributors to loss of self-tolerance.^7,8

Thyroid hormones play a role in the development, differentiation and metabolic maintenance of virtually all tissues, which is a topic that is beyond the scope of this blog. Of interest, thyroid hormones help regulate the body’s response to stress. Additionally, thyroid hormones directly influence the synthesis, release and degradation of key neurotransmitters associated with stress and mood regulation, including serotonin, dopamine and gamma-aminobutyric acid (GABA).

Suboptimal thyroid function often disrupts the hypothalamic-pituitary-adrenal (HPA) axis, which can alter one’s ability to maintain resilience to the stressors of life while also worsening occasional anxious feelings. There are two categories of stressors:

• External: Such as post-traumatic events, work, relationships and finances.
• Physiological: Such as nutrient insufficiencies, toxin burden, overactivation of the 
  immune system and cytokine function.

When an individual experiences stress, the HPA axis is activated, leading to increased production of cortisol. This is when the interconnected hypothalamic-pituitary-thyroid-adrenal (HPTA) axis becomes apparent. Elevated cortisol levels can inhibit the conversion of T4 to its active form T3, resulting in suboptimal thyroid function. Additionally, stress can lead to changes in production of reverse T3, which is biologically inactive and competes with T3 for cellular receptors.⁹ Finally, stress has been implicated as a trigger for loss of self-tolerance and an increased production of thyroid antibodies.¹⁰ The feedback loop in the HPTA axis creates a potential pathway through which stress and low functioning thyroid are interconnected. 

The relationship between stress and suboptimal thyroid can also contribute to the development of occasional anxious feelings. Thyroid hormones play a role in regulating the central nervous system (CNS) and the limbic system, which are critical for mood stabilization and emotional processing. Thyroid function in need of support can affect the synthesis and availability of  neurotransmitters such as serotonin, dopamine and gamma-aminobutyric acid (GABA), which are essential for maintaining a calm and balanced emotional state.¹¹ In fact, nutrients that are needed for the proper production of thyroid hormones also play a role as co-factors for the production of these neurotransmitters, including, but not limited to, B vitamins, zinc, vitamin C and the amino acid tyrosine.^‡

Nutrition: A nutrient-dense diet that supports thyroid health, neurotransmitter production, and modulates cytokine response can be effective in managing stress and emotional well-being. Emphasizing foods rich in selenium (e.g., Brazil nuts), iodine (e.g., seaweed, seafood, dairy, eggs, poultry) and zinc (e.g., pumpkin seeds, lean meats) should serve as a foundation. The Mediterranean Diet, known for its anti-inflammatory properties, has been shown to improve emotional regulation and support the neuroendocrine system.¹²

Exercise: Aerobic activities, such as walking or cycling, have been found to enhance the conversion of T4 to T3 and increase the sensitivity of cellular receptors to thyroid hormones. Additionally, yoga and tai chi, which integrate physical movement with mindfulness, have demonstrated efficacy in reducing stress and promoting thyroid health.¹³

Sleep: Suboptimal thyroid function may lead to sleep disturbances. Poor sleep aggravates occasional anxiety by impacting neurotransmitters and can lead to the increased production of stress hormones. Prioritizing 7-9 hours of restorative sleep per night, maintaining a consistent sleep schedule and creating a calming pre-sleep routine can help optimize thyroid function, modulate stress responses and promote a calm mood.

Stress Management: Mind-body practices such as mindfulness meditation, deep breathing exercises, guided imagery and progressive muscle relaxation have been shown to provide effectiveness on the psychological and physiological levels.¹⁴

Iodine is a vital nutrient for the synthesis of T4. While adequate iodine intake is essential for maintaining thyroid function, it should be approached cautiously, especially in individuals with a self-tissue response.^‡ 

Selenium is a critical cofactor for the enzyme deiodinase, which converts T4 to T3. Generally, individuals will consume enough of this nutrient in their diet. It is important to be aware of potential selenium toxicity from excess consumption.¹⁵

Zinc is an essential trace mineral involved in the conversion of T4 to T3 and is a needed cofactor for the regulation of neurotransmitters. B Vitamins particularly B6, B9 (folate) and B12, play a role in T4 production, and neurotransmitter synthesis. These vitamins also help improve the body’s response to stress.^‡

Myo-inositol is the primary form of inositol found in the central nervous system. It plays an important role in cell membrane formation and serves as part of the phosphatidylinositol secondary messenger system, supporting serotonin, norepinephrine and cholinergic receptor function.^16‡

Studies have shown that combined use of Selenium methionine and Myo-inositol can support feelings of well-being, thyroid hormone production and healthy TSH, TPO and TG antibody levels.^{17,18 ‡}

L-Tyrosine is an amino acid that serves as a precursor for the synthesis of thyroid hormones and the neurotransmitter, dopamine. 

GABA is an inhibitory neurotransmitter and amino acid that promotes calmness and relaxation. It plays a significant role in regulating the HPA axis and reducing the body's stress response. ^‡

L-Theanine, an amino acid found in green tea, has been shown to promote relaxation by modulating glutamate (the excitatory neurotransmitter) function, and possibly the GABA, system as well.^{19 ‡}

Ashwagandha (Withania somnifera) is an adaptogenic herb known for its ability to reduce stress and support thyroid health. Research indicates that ashwagandha can lower cortisol levels, support thyroid hormone production and enhance overall well-being.²⁰ 

Pure Encapsulations® provides uniquely formulated products made with high-quality, 
pure ingredients backed by verifiable science to complement your plan of care and support 
healthy aging in your patients.^‡

Thyroid Support Complex: Supports optimal thyroid gland function, healthy thyroid cell 
metabolism and thyroid hormone function^‡

Suggested Use: As a dietary supplement, take 2 capsules daily, with a meal.

Daily Stress Formula: Promotes mental relaxation and moderates the effects of 
occasional stress, supports the body’s resilience when faced with occasional stress and
helps moderate mild fatigue under stressful conditions^‡
 
Suggested Use: As a dietary supplement, take 3 capsules daily, with or between meals.

L-Theanine: Promotes relaxation, with Suntheanine®, without causing drowsiness^‡

Suggested Use: As a dietary supplement, children ages 8-18, take 1 capsule, 1-2 times 
daily, between meals. Adults, take 2 capsules, 1-3 times daily, between meals.

Zinc 30: Broad physiological support, including immune function and emotional wellness^‡

Suggested Use: As a dietary supplement, take 1 capsule, 1-2 times daily, with a meal.

Selenium (selenomethionine): Supports antioxidant defenses, immune function and 
cellular health^‡

Suggested Use: As a dietary supplement, take 1 capsule daily, with a meal, or as directed 
by a health professional.

GABA: Promotes relaxation and moderates occasional stress. May also support immune 
health during occasional stress.^‡

Suggested Use: As a dietary supplement, take 1 capsule daily, between meals, or as 
directed by a health professional.

DopaPlus 180’s: Promotes the production of dopamine to support daily cognitive function 
and performance on mental tasks while also supporting mood.^‡

Suggested Use: As a dietary supplement, take 3 capsules, 1-2 times daily, with low protein 
foods.

SeroPlus: Promotes serotonin synthesis to support relaxation, moderate occasional stress 
and maintain healthy eating behavior. Provides neurotransmitter precursors to help 
balance serotonin function and maintains healthy serotonin activity and reuptake.^‡

Suggested Use: As a dietary supplement, take 2 capsules, 1-2 times daily, between meals.

NeuroPure 120’s: Provides enhanced support for emotional balance and mood stability
while supporting overall neurotransmitter function and neuronal health.^‡

Suggested Use: As a dietary supplement, take 2 capsules, 1-2 times daily, between meals.

Inositol Complex: May support healthy mood, emotional wellness and behavior and helps 
lessen occasional nervous tension.^‡

Suggested Use: as a dietary supplement, take 1 capsule, twice daily with meals.

The intricate connection between stress, occasional anxiousness, and thyroid health underscores the importance of a holistic approach to wellness. By understanding the role of the HPT and HPTA axes, as well as the impact of lifestyle factors and nutrient support, individuals can take proactive steps to better manage their thyroid health and emotional well-being. Prioritizing a nutrient-dense diet, stress management techniques, quality sleep, and appropriate supplementation can create a foundation for resilience and balance. While navigating these interconnections can be complex, informed choices and integrative strategies offer a pathway to improved overall health

Thyroid Support Protocol^‡: Designed by our clinician partners to help you deliver the most effective care and support for your patient's thyroid.

Drug-Nutrient Interaction Checker:  Provides valuable information on potential interactions between your patients' prescriptions, over-the-counter medications and nutritional supplements.

PureInsight™: Our streamlined platform easily collects patient data and provides valuable recommendations to help achieve their health goals.

Virtual Dispensary: Our Pure Patient Direct program provides account holders FREE access to our virtual dispensary to help simplify patient sales and reduce in-office inventory.

You can also explore Pure Encapsulations^® to find On-Demand Learning, Clinical Protocols and other resources developed with our medical and scientific advisors.

1. American Psychiatric Association. American Adults Express Increasing Anxiousness in Annual Poll; Stress and Sleep are Key Factors Impacting Mental Health. American Psychiatric Association. May 1, 2024. Accessed November 11, 2024. https://www.psychiatry.org/news-room/news-releases/annual-poll-adults-express-increasing-anxiousness
2. American Thyroid Association. Prevalence and Impact of Thyroid Disease. American Thyroid Association. Accessed November 11, 2024. https://www.thyroid.org/media-main/press-room/
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   https://medlineplus.gov/druginfo/meds/a682461.htm
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   doi:10.20452/pamw.16222
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   doi:10.7759/cureus.50199
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    doi:10.3389/fendo.2023.1210540
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    doi:10.1007/s40618-023-02169-2
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    doi:10.3390/cimb45020113
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    Pharmacol Sci. 2017;21(2).
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    J AIect Disord. 2023;333. doi:10.1016/j.jad.2023.04.029
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    doi:10.3390/ijms242216513