What does the evidence show about Iodine's effects?

Read Off Label rates the evidence for Iodine as Strong and the benefit magnitude as high, producing an overall grade of A- (7.6/10). Both deficiency and excess cause thyroid dysfunction — narrow therapeutic window.

What safety findings are reported for Iodine?

Iodine has a low-med risk profile in the database. Low-Med (excess causes thyroid dysfunction) Legal status: OTC.

What doses or routes are reported for Iodine?

150 mcg/day adults; 250 mcg during pregnancy/lactation; via iodized salt, seaweed, dairy, or supplement This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.

Rankings / Essentials — Vitamins & Minerals

Iodine

Essentials · Mineral

Tier A-

Reviewed by Read Off Label · Last reviewed Jun 8, 2026 · How we grade

thyroidmineralotc

7.6 / 10

Tier A-

Ev 8 Bn 8 Sf 7

Bottom line

Read Off Label grades Iodine as A- (7.6/10) based on strong evidence, high benefit magnitude, and a low-med-risk safety profile.

Both deficiency and excess cause thyroid dysfunction — narrow therapeutic window.

Studied, labeled, or reported-use context: 150 mcg/day adults; 250 mcg during pregnancy/lactation; via iodized salt, seaweed, dairy, or supplement — OTC; not individualized guidance.

What the evidence says

Both deficiency and excess cause thyroid dysfunction — narrow therapeutic window. Severe deficiency in pregnancy causes cretinism. Mild-moderate deficiency still common outside iodized-salt regions. Pharmacologic dosing: potassium iodide (KI) and potassium iodate (KIO3) tablets (65-130 mg) are stockpiled for thyroid blockade after radioactive iodine exposure (Chernobyl/Fukushima protocol); not a daily supplement.

Mechanism

Substrate for thyroid hormones T3/T4 — required for metabolism, neurodevelopment, and thyroid function

Studied, labeled, or reported dose & route

150 mcg/day adults; 250 mcg during pregnancy/lactation; via iodized salt, seaweed, dairy, or supplement

This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.

Citations

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Common questions

What does the evidence show about Iodine's effects?: Read Off Label rates the evidence for Iodine as Strong and the benefit magnitude as high, producing an overall grade of A- (7.6/10). Both deficiency and excess cause thyroid dysfunction — narrow therapeutic window.
What safety findings are reported for Iodine?: Iodine has a low-med risk profile in the database. Low-Med (excess causes thyroid dysfunction) Legal status: OTC.
What doses or routes are reported for Iodine?: 150 mcg/day adults; 250 mcg during pregnancy/lactation; via iodized salt, seaweed, dairy, or supplement This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
How does Iodine work?: Substrate for thyroid hormones T3/T4 — required for metabolism, neurodevelopment, and thyroid function

This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.