The Thyroid and Supplements… what the science says!
The thyroid is the powerhouse of the body, controlling metabolism, energy, and overall well-being. But when it’s not functioning optimally, symptoms like fatigue, weight gain, brain fog, and hair loss can take over.
Many people turn to supplements in hopes of supporting their thyroid health—but not all are backed by science. Today, we’re diving into the best thyroid-supporting supplements, what the research actually says, and how to make the right choices for your health.
1. Iodine: The Essential Thyroid Nutrient
Why it matters: The thyroid needs iodine to produce hormones, particularly T3 (triiodothyronine) and T4 (thyroxine). Without enough iodine, thyroid function slows down, leading to hypothyroidism and goiter.
What science says:
Studies confirm that iodine deficiency is a leading cause of hypothyroidism worldwide. (Zimmermann & Boelaert, 2015)
However, too much iodine can also be a problem, particularly for people with Hashimoto’s, potentially triggering or worsening autoimmune attacks. (Leung et al., 2012)
Best sources:
Food first – seaweed, fish, dairy, and eggs provide natural iodine.
Supplements – best taken only if you are deficient (excess can be harmful).
2. Selenium: The Antioxidant Shield
Why it matters: Selenium is critical for converting T4 into active T3 and protecting the thyroid from oxidative stress.
What science says:
Selenium supplementation reduces thyroid peroxidase (TPO) antibodies in Hashimoto’s, meaning it may slow disease progression. (Wichman et al., 2016)
Selenium deficiency is linked to thyroid dysfunction and increased risk of goiter. (Vanderpas et al., 1990)
Best sources:
Food first – Brazil nuts, fish, eggs, and meats are selenium-rich.
Supplements – If deficient, 200 mcg/day is the studied dose. (Winther et al., 2020)
3. Zinc: The T3 Booster
Why it matters: Zinc helps with T3 production and thyroid hormone receptor function, influencing metabolism and immune health.
What science says:
Zinc deficiency is linked to low T3 levels and sluggish metabolism. (Sajadian et al., 2021)
Supplementing with zinc improves T3 levels in hypothyroid patients. (Hagmeyer et al., 2022)
Best sources:
Food first – oysters, beef, pumpkin seeds, and eggs.
Supplements – 10–30 mg/day if deficient.
4. Magnesium: The Relaxation Mineral
Why it matters: Magnesium helps activate T4 into T3, regulates the stress response, and supports adrenal-thyroid balance.
What science says:
Magnesium reduces inflammation and supports thyroid function. (Rondanelli et al., 2021)
Deficiency is associated with hypothyroidism and increased risk of Hashimoto’s. (Davis et al., 2018)
Best sources:
Food first – dark leafy greens, nuts, seeds, and avocado.
Supplements – Magnesium glycinate is the best-absorbed form.
5. Vitamin D: The Immune Modulator
Why it matters: Low vitamin D is strongly linked to thyroid disorders, especially autoimmune thyroid diseases like Hashimoto’s and Graves’.
What science says:
People with hypothyroidism often have low vitamin D levels. (Bozkurt et al., 2013)
Supplementing with vitamin D reduces thyroid antibodies in Hashimoto’s. (Mazokopakis et al., 2015)
Best sources:
Food first – fatty fish, egg yolks, and sunshine.
Supplements – Aim for 2,000–5,000 IU/day, especially in winter.
6. Iron: The Oxygen Carrier
Why it matters: Iron is essential for thyroid hormone production and energy metabolism. Low iron = low T3.
What science says:
Iron deficiency is common in hypothyroid women, worsening fatigue and hair loss. (Almourfi et al., 2020)
Supplementing with iron improves T3 levels and thyroid function. (Hess et al., 2010)
Best sources:
Food first – red meat, liver, spinach, and legumes.
Supplements – If needed, heme iron (from animal sources) is best absorbed.
7. B Vitamins: The Energy Producers
Why they matter: B vitamins support thyroid hormone synthesis, metabolism, and adrenal function.
What science says:
B12 deficiency is common in hypothyroidism, leading to fatigue and brain fog. (Mansoori et al., 2019)
B6 and B2 help with T4 to T3 conversion. (Palsdottir et al., 2021)
Best sources:
Food first – meat, eggs, leafy greens, and dairy.
Supplements – A B-complex ensures you get a balanced intake.
What This Means for You
Start with food first – Whole foods provide the best nutrients in the right balance.
Test, don’t guess – If you suspect deficiencies, get lab work done before supplementing.
Be cautious – More isn’t always better, especially with iodine and iron.
Want a deeper dive into thyroid health?
Stay tuned for more evidence-based insights, and if you’re ready to take control of your thyroid, check out The Thyroid Reset Course for step-by-step guidance.
Disclaimer: The information provided in this article is for educational purposes only and is not intended to diagnose, treat, or cure any medical condition. Always consult with a qualified healthcare professional before making any changes to your diet, lifestyle, or treatment plan. Individual needs may vary, and what works for one person may not be suitable for another.
