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Lugol's Iodine Solution

A concentrated iodine-iodide solution that delivers milligram doses, far beyond nutritional needs. Correcting genuine iodine deficiency helps, but self-dosing Lugol's is a well-documented way to trigger thyroid dysfunction.

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What the science says

  • Correcting deficiency benefits thyroid function Moderate evidence

    A systematic review and meta-analysis of iodine supplementation in mildly-to-moderately iodine-deficient pregnant women found improvements in maternal thyroid function markers, though child neurodevelopment outcomes were not clearly improved. The benefit applies to deficiency, at microgram doses.

  • Excess iodine causes thyroid dysfunction Strong evidence

    Reviews of excess iodine intake document both iodine-induced hypothyroidism and hyperthyroidism, with risk rising sharply above the tolerable upper intake of about 1,100 µg/day in adults. A single drop of Lugol's can exceed that many times over.

  • Excess in pregnancy is a documented problem Moderate evidence

    A systematic review and meta-analysis of excessive iodine intake in pregnancy found associations with maternal thyroid abnormalities. More is not better in this population.

Dosage & safety

Studied doseNutritional requirement is 150 µg/day for adults and 220–290 µg/day in pregnancy and lactation. Lugol's 5% supplies roughly 6 mg of iodine per drop, so it is a pharmaceutical-strength preparation and should only be used at doses set by a clinician.
SafetyCan precipitate hypothyroidism, hyperthyroidism or thyroiditis, particularly in people with nodular goitre, Hashimoto's or Graves' disease. Also causes iodine acne, metallic taste, gastrointestinal upset and, rarely, hypersensitivity. Do not self-treat thyroid conditions with it; avoid in pregnancy other than under medical supervision, and note the interaction with lithium and amiodarone.

How to take it

TimingOnly on a schedule set by a clinician — this is a pharmaceutical-strength preparation, not a daily multivitamin.
With food?Dilute it in water or juice and take it with food; undiluted drops irritate the mouth and stomach.
Worth knowingOne drop of 5% Lugol's supplies about 6 mg of iodine — roughly 40 times the daily requirement — so a dropper is the wrong instrument for meeting a nutritional need.

Interactions

With medications

  • lithium

    Both suppress thyroid function, and together they markedly raise the risk of hypothyroidism and goitre. Do not use iodine supplements without thyroid monitoring

  • amiodarone

    Amiodarone is already an enormous iodine load, and adding more can trigger thyroid dysfunction. Do not combine

  • carbimazole, methimazole and propylthiouracil

    Additive suppression of thyroid hormone production. Only use iodine alongside these drugs when a clinician has prescribed it

  • ACE inhibitors and potassium-sparing diuretics

    Potassium iodide preparations add a potassium load that these drugs cause you to retain. Do not use potassium iodide products without medical supervision

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Is it safe to take Lugol's iodine daily?

Self-dosing Lugol's iodine is a well-documented way to trigger thyroid dysfunction: excess iodine causes both hypothyroidism and hyperthyroidism (strong evidence), with risk rising above about 1,100 mcg/day. One drop of 5% Lugol's supplies about 6 mg of iodine, so use it only at doses set by a clinician.

How much iodine do I need per day?

Adults need 150 mcg of iodine per day, rising to 220–290 mcg/day in pregnancy and lactation. Lugol's 5% supplies roughly 6 mg per drop, about 40 times the daily requirement, so it is the wrong tool for meeting a nutritional need.

Should I take Lugol's iodine for my thyroid?

Do not self-treat thyroid conditions with Lugol's iodine: it can precipitate hypothyroidism, hyperthyroidism or thyroiditis, particularly with nodular goitre, Hashimoto's or Graves' disease. Correcting genuine iodine deficiency at microgram doses helps thyroid function; milligram doses do not.

Can I take Lugol's iodine with lithium or amiodarone?

Do not combine Lugol's iodine with amiodarone, which is already an enormous iodine load, and do not use it with lithium without thyroid monitoring, as the combination markedly raises the risk of hypothyroidism and goitre. It also adds to carbimazole, methimazole and propylthiouracil.

Scientific references

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