Deficiency/Hormonal/Women

Iodine

Essential trace mineral for thyroid hormone production and deficiency prevention, most useful for low-iodine diets and pregnancy.

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evidence

Caution

risk

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Use with caution

This supplement may interact with medications, medical conditions or sensitive populations. Review safety before use.

Overview

Forms

Safety

Stack

Quick Take

Worth it if you avoid iodized salt or are pregnant/lactating; otherwise extra iodine is usually unnecessary and can backfire.

Iodine is an essential trace mineral found in iodized salt, dairy, seafood, eggs, and some seaweeds. The thyroid uses it to make T4 and T3; when intake is low, TSH rises and the gland can enlarge. Supplementation mainly corrects low iodine status, lowers deficiency-related goiter and abnormal thyroid labs, and supports maternal and infant iodine supply when intake is low in pregnancy or lactation. It helps most people who use little iodized salt or eat little seafood and dairy.

Potential benefits

Corrects iodine deficiency

Reduces goiter from low iodine

Normalizes TSH/T4 in insufficiency

Raises breast-milk iodine

Supports fetal neurodevelopment

May reduce cyclic breast pain

Protocol

Amount

150 mcg

Frequency

Once daily

When

Any time of day — consistency matters more than timing; take with food if it causes nausea.

Onset Time

2-6 weeks for iodine status; 2-6 months for goiter/thyroid changes

Who Should Consider

Adults using non-iodized salt

Vegans with little dairy or seafood

People who rarely eat seafood

Women trying to conceive

Pregnant women

Lactating women

Food Sources

Iodized salt (~70 mcg per 1/4 tsp)
Cod or haddock (~90-100 mcg per 85 g)
Milk or yogurt (~50-80 mcg per cup)
Eggs (~20-25 mcg each)
Nori seaweed (~20-60 mcg per sheet; kelp can be far higher)

How It Works

Iodine is absorbed as iodide, transported into the thyroid by the sodium-iodide symporter, and attached to tyrosine residues on thyroglobulin to form T4 and T3. Low intake limits hormone synthesis, which raises TSH and can enlarge the thyroid.

Updated 5/19/2026