Medically Reviewed by Lucas Rosa, PhD in Molecular Biology

There’s a small butterfly-shaped gland in your neck that quietly controls nearly every function in your body. It’s called the thyroid, and it produces thyroid hormones – some of the most essential messengers in your endocrine system.

These hormones impact metabolism, heart rate, temperature regulation, weight, energy levels, mood, digestion, and even fertility. When thyroid hormones are balanced, you likely won’t even think about them. But when they’re too high or too low, your body lets you know – often with symptoms that can be confusing, frustrating, and far-reaching.

In this article, we’ll explore what thyroid hormones are, what they do, how they’re made, the signs of imbalance, and practical, natural ways to keep your thyroid working its best.

What Are Thyroid Hormones?

Thyroid hormones are chemical messengers made by the thyroid gland that help regulate your body’s metabolism and maintain vital functions. The two main types are:

• T4 (Thyroxine): The storage form that makes up about 90% of your thyroid output.
• T3 (Triiodothyronine): The active form; it’s converted from T4 and does the real work in your cells.

Another key player is TSH (Thyroid Stimulating Hormone), which is produced by the pituitary gland. TSH tells your thyroid when and how much thyroid hormone to make, maintaining a feedback loop between your brain and thyroid.

How Are They Made?

The thyroid gland, located at the front of your neck, uses iodine from your diet to make thyroid hormones. Here’s a quick breakdown:

1. The hypothalamus (in your brain) detects low hormone levels and signals the pituitary gland.
2. The pituitary releases TSH.
3. TSH stimulates your thyroid to produce T4 and T3.
4. T4 travels through the bloodstream to your liver and other organs, where it’s converted into T3.
5. T3 enters cells and controls how fast or slow your body’s processes work.

It’s a delicate system that depends on nutrients, enzymes, and balance between multiple hormones.

What Do Thyroid Hormones Do?

Your thyroid hormones influence nearly every cell in your body. (1) Key roles include:

• Regulating metabolism (how your body turns food into energy)
• Controlling body temperature
• Maintaining heart rate and rhythm
• Supporting brain function and mood stability
• Regulating menstrual cycles and fertility
• Influencing digestion and gut motility
• Supporting hair growth, skin renewal, and weight maintenance

A healthy thyroid keeps all these systems humming quietly in the background. But when there’s a problem, you’ll feel it.

Symptoms of Thyroid Hormone Imbalances

Thyroid hormone issues are usually either hypothyroidism (too little hormone) or hyperthyroidism (too much hormone).

Hypothyroidism (Underactive Thyroid)

Common signs include:

• Fatigue and low energy
• Weight gain
• Cold sensitivity
• Depression
• Constipation
• Dry skin and brittle nails
• Hair thinning or loss
• Slow heart rate
• Heavy periods
• Brain fog and memory issues

Hyperthyroidism (Overactive Thyroid)

Common signs include:

• Weight loss despite eating well
• Anxiety or irritability
• Rapid or irregular heartbeat
• Sweating and heat intolerance
• Tremors
• Insomnia
• Frequent bowel movements
• Muscle weakness
• Light or missed periods

Either state disrupts your overall hormonal balance and requires attention – both medically and through lifestyle support.

Causes of Thyroid Hormone Imbalances

Several factors can trigger thyroid hormone disruption:

• Nutrient deficiencies (especially iodine, selenium, zinc, and iron)
• Chronic stress (elevates cortisol, which suppresses TSH and conversion of T4 to T3)
• Autoimmune diseases like Hashimoto’s thyroiditis or Graves’ disease
• Poor gut health (since the gut converts and activates thyroid hormones)
• Toxin exposure, especially heavy metals and endocrine disruptors
• Food sensitivities, particularly gluten (can cross-react with thyroid tissue)
• Overuse of certain medications, like lithium or steroids
• Pregnancy and post-partum hormonal shifts

Natural Ways to Keep Thyroid Hormones Balanced

While some thyroid disorders require medical treatment, supporting your thyroid naturally can go a long way in preventing issues and improving overall balance.

1. Ensure Sufficient Iodine Intake

Iodine is the building block of thyroid hormones. Without it, your body can’t make enough T3 and T4. (2)

• Sources: seaweed (kelp, nori), iodized salt, eggs, yogurt, fish
• Don’t overdo iodine because too much can also cause problems

2. Add Selenium-Rich Foods

Selenium helps convert T4 to T3 and reduces inflammation in the thyroid. (3)

• Sources: Brazil nuts, sunflower seeds, sardines, eggs

3. Boost Zinc and Iron Levels

These minerals support thyroid hormone production and activation.

• Zinc sources: pumpkin seeds, chickpeas, beef, lentils
• Iron sources: spinach, red meat, tofu, beans, dried apricots

Low ferritin (iron storage) is often a hidden cause of hair loss and fatigue in thyroid issues.

4. Manage Stress and Lower Cortisol

High stress inhibits TSH and interferes with hormone conversion. (4)

• Try: breathwork, meditation, walking outdoors, yoga, consistent sleep

For more strategies to manage stress, visit this blog.

5. Heal and Support Gut Health

A large portion of T4 is converted into T3 in the gut. Poor digestion means poor hormone function. (5)

• Add: fermented foods (sauerkraut, kimchi, kefir), probiotics, fiber
• Reduce inflammatory foods like sugar and alcohol

6. Avoid Endocrine Disruptors

Toxins from plastic, pesticides, and personal care products can harm your thyroid over time.

• Choose organic produce when possible
• Use glass or bamboo containers instead of plastic
• Switch to natural personal care products
• Filter your drinking water

7. Don’t Overtrain

Excessive high-intensity exercise can stress the body and lower thyroid function. Prioritize balance:

• Include light movement like walking, strength training, yoga, or cycling
• Ensure you recover with sleep and nutrition

8. Prioritize Sleep

Poor sleep affects every hormone, including your thyroid. Aim for 7–9 hours of quality sleep each night to allow your endocrine system to reset.

Conclusion

Your thyroid hormones may be small in quantity, but they have massive effects on your health. From your energy levels to metabolism, skin health to mental clarity, these hormones quietly run the show. And when they fall out of sync, the consequences are hard to ignore.

While some thyroid conditions need medical treatment, many people can support and protect their thyroid through diet, stress reduction, gut health, and toxin-free living. The key is staying aware of early signs, testing your levels if needed, and making intentional daily choices to fuel your body and your hormones.

Your thyroid is working hard every day. Make sure you’re giving it the support it deserves.

References

1. Shahid MA, Ashraf MA, Sharma S. Physiology, Thyroid Hormone. [Updated 2023 Jun 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK500006/
2. Sun X, Shan Z, Teng W. Effects of increased iodine intake on thyroid disorders. Endocrinol Metab (Seoul). 2014 Sep;29(3):240-7. doi: 10.3803/EnM.2014.29.3.240. PMID: 25309781; PMCID: PMC4192807.
3. Vargas-Uricoechea H, Urrego-Noguera K, Vargas-Sierra H, Pinzón-Fernández M. Zinc and Ferritin Levels and Their Associations with Functional Disorders and/or Thyroid Autoimmunity: A Population-Based Case-Control Study. Int J Mol Sci. 2024 Sep 23;25(18):10217. doi: 10.3390/ijms251810217. PMID: 39337701; PMCID: PMC11432327.
4. Sinha SR, Prakash P, Keshari JR, Kumari R, Prakash V. Assessment of Serum Cortisol Levels in Hypothyroidism Patients: A Cross-Sectional Study. Cureus. 2023 Dec 8;15(12):e50199. doi: 10.7759/cureus.50199. PMID: 38192949; PMCID: PMC10772313.
5. Knezevic J, Starchl C, Tmava Berisha A, Amrein K. Thyroid-Gut-Axis: How Does the Microbiota Influence Thyroid Function? Nutrients. 2020 Jun 12;12(6):1769. doi: 10.3390/nu12061769. PMID: 32545596; PMCID: PMC7353203.