Iodine

Also known as: potassium iodide, lugols iodine

Grade A — Strong Evidencemineralfoundationalthyroid
150–300 mcgWith food

Iodine is an essential trace element required for thyroid hormone synthesis (T3 and T4), which regulate metabolism, growth, and neurodevelopment. Deficiency remains the leading preventable cause of intellectual disability worldwide, though iodized salt has reduced prevalence in developed nations. Supplementation is critical during pregnancy and lactation; however, excess iodine can paradoxically suppress thyroid function, particularly in those with underlying Hashimoto's thyroiditis.

TL;DR: Essential trace mineral for thyroid hormone synthesis. Critical for metabolic rate and cognitive development. Most people get enough from iodized salt — test before supplementing.

⚡Energy🧠Cognitive Performance🧬Longevity
Last reviewed: 2026-03-12

Quick Facts

Evidence

Grade A

Studies

2

Interactions

3

Forms

1

Evidence Rating: Grade A — Strong Evidence

Multiple high-quality RCTs, systematic reviews, or meta-analyses with consistent findings.

Interaction Warnings

Thyroid medications (levothyroxine)High Risk

Excess iodine can interfere with thyroid hormone synthesis and medication efficacy. Discuss with endocrinologist.

Antithyroid drugs (methimazole, PTU)High Risk

Iodine supplementation may interfere with antithyroid treatment.

LithiumModerate

Lithium and iodine both affect thyroid function; combined use may cause hypothyroidism.

Important Notes

  • Supplementation not necessary if eating iodized salt or seafood regularly
  • High doses (>1mg) can paradoxically suppress thyroid (Wolff-Chaikoff effect)
  • Hashimoto thyroiditis: caution with iodine supplementation
  • Get thyroid function tested if supplementing long-term

Clinical Evidence (2 studies)

Iodine deficiency and cognitive development

Zimmermann MB (2009) — Endocr Rev

Iodine deficiency is the leading preventable cause of cognitive impairment worldwide; supplementation restores cognitive function in deficient populations

View on PubMed

Thyroid hormones and metabolic rate

Maia AL et al. (2011) — Arq Bras Endocrinol Metabol

Adequate iodine essential for normal thyroid hormone synthesis and metabolic regulation

View on PubMed

Alternatives to Consider

These supplements target similar goals and may be worth considering alongside or instead of Iodine.

Omega-3 Fish Oil

Grade A

Essential fatty acids with strong evidence for cardiovascular and mental health. EPA-dominant for mood; triglyceride form for absorption.

🧠 Cognitive Performance🧬 Longevity

Vitamin B12

Grade A

Critical for nerve function, DNA synthesis, and red blood cell formation. Vegans, elderly, and metformin users are at high risk of deficiency. Methylcobalamin preferred for neurological benefit.

🧠 Cognitive Performance🧬 Longevity

Folate (Vitamin B9)

Grade A

Essential for DNA synthesis, methylation, and mood regulation. ~40% of people have MTHFR variants reducing conversion — use methylfolate. Always pair with B12.

🧠 Cognitive Performance🧬 Longevity

Related Supplements

PQQ (Pyrroloquinoline Quinone)

Grade C — Preliminary

Stimulates mitochondrial biogenesis (creation of new mitochondria). Best paired with CoQ10. Still early research.

L-Carnitine

Grade B — Moderate Evidence

Amino acid derivative critical for fatty acid transport into mitochondria. ALCAR crosses the blood-brain barrier for cognitive support. Good evidence for exercise performance and male fertility.

Shilajit

Grade B — Moderate Evidence

Mineral-rich resin from Himalayan rock. Contains fulvic acid and 80+ trace minerals. Promising evidence for testosterone, mitochondrial function, and cognitive health. Quality and purity are critical.

Alpha-Lipoic Acid

Grade B — Moderate Evidence

Unique antioxidant active in both water and fat-soluble environments. Evidence for blood sugar regulation, neuropathy, and oxidative stress reduction. The R-form is more bioavailable. Useful for metabolic health and neuroprotection.

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⚕️ Important Disclaimer

This information is for educational purposes only. It is not medical advice. Always consult a healthcare provider before starting any supplement regimen, especially if you take medications or have health conditions.

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