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evidence · mechanism · dose
Supplements/Mineral

Iodine

aka Potassium iodide · Kelp

Halogen essential for thyroid hormone synthesis.

Hormone OptimizationGeneral Wellness

Overview

Halogen essential for thyroid hormone synthesis.

Natural sources
  • Iodized salt
  • Seaweed
  • Dairy
  • Eggs
Common forms
  • Potassium iodide
  • Kelp
  • Lugol's solution

Forms & variants of Iodine

Different chemical forms of Iodine behave differently. Browse each form's mechanism, bioavailability, and best-use context.

Potassium Iodide
Potassium Iodide

Standard inorganic iodine — thyroid hormone precursor and radioprotectant.

Lugol's solution
Lugol's Iodine

Combined iodine/iodide solution used historically for thyroid support.

Mechanism of action

Incorporated into thyroglobulin to form T4 and T3.

Pathways
  • · Thyroid hormone synthesis

Effects on the body

Supports
Thyroid hormone synthesis

Organ system effects

Endocrine

Required for T3/T4; deficiency causes goiter.

Evidence-based benefits

Prevents goiter and cretinism in deficient populations

Strong evidence

Potential side effects

Common
    Rare
    • · Acne flare
    Serious
    • · Hypo- or hyperthyroidism at extreme doses

    Drug interactions

    Amiodarone
    Already iodine-rich.
    moderate
    Lithium
    Both can cause hypothyroidism.
    moderate

    Supplement interactions

    Pairs well with

    None listed.

    Avoid combining with

    No specific avoidances listed.

    Dosing & bioavailability

    Typical dose
    150 mcg adults; 220 mcg pregnancy
    Upper safe limit
    1,100 mcg

    Where to buy

    Affiliate-style search links to reputable retailers. We don't endorse specific brands — verify third-party testing (USP, NSF, Informed Sport) before purchase.

    Mineral
    Iodine
    Amazon
    Wide selection · fast shipping
    Mineral
    Iodine
    iHerb
    Global delivery · curated brands
    Mineral
    Iodine
    Thorne
    Practitioner-grade · NSF tested

    Scientific evidence (8)

    Systematic reviewExamine.com Supplement Database · 2023

    Iodine: pharmacology, clinical evidence, and safety — narrative review

    Examine.com Research Team

    Curated narrative review of human and preclinical evidence for Iodine, including mechanism, typical dosing, and safety considerations.

    Key findings

    Best-supported outcome: Prevents goiter and cretinism in deficient populations (evidence: strong). Additional outcomes and limitations summarized in the full profile.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: Iodine — Prevents goiter and cretinism in deficient populations

    Live PubMed search

    Live results for "Iodine Prevents goiter and cretinism in deficient populations" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching Iodine and "Prevents goiter and cretinism in deficient populations". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: Iodine — randomized controlled trial

    Live PubMed search

    Live results for "Iodine randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching Iodine and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: Iodine — meta-analysis

    Live PubMed search

    Live results for "Iodine meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching Iodine and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: Iodine — pharmacokinetics

    Live PubMed search

    Live results for "Iodine pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching Iodine and "pharmacokinetics". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: Iodine — safety adverse events

    Live PubMed search

    Live results for "Iodine safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching Iodine and "safety adverse events". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewPubMed (NLM) · 1970

    PubMed: Iodine — dose response

    Live PubMed search

    Live results for "Iodine dose response" across the PubMed/MEDLINE peer-reviewed index.

    Key findings

    Opens current human and preclinical literature matching Iodine and "dose response". Filter by RCT, meta-analysis, or year on the results page.

    Open study
    Systematic reviewGoogle Scholar · 1970

    Google Scholar: Iodine — clinical evidence

    Live Scholar search

    Cross-database citation index for Iodine as it relates to "clinical evidence".

    Key findings

    Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

    Open study
    Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.