Iodine

Iodine supplements often provide around 150 µg per day, but the source can differ substantially. This guide explains what iodine does, why kelp deserves special dose attention and what to compare before choosing a product.

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In this guideIngredient basics, choosing & product comparison

What is iodine?

Iodine is an essential trace mineral needed for the normal production of thyroid hormones. Dietary sources include fish, dairy products, eggs and iodised salt. Seaweeds can also contain iodine, but their iodine content can vary widely depending on species and growing conditions.

What does iodine support?

Iodine contributes to the normal production of thyroid hormones and normal thyroid function. It also supports normal cognitive and nervous-system function, energy-yielding metabolism and the maintenance of normal skin.

What happens if you don’t get enough iodine?

Too little iodine can reduce thyroid hormone production. Goitre — an enlarged thyroid gland — is often an early visible sign of iodine deficiency. More severe deficiency can lead to hypothyroidism. Iodine is particularly important during pregnancy and early life because thyroid hormones are needed for normal brain and nervous-system development.

Iodine status is not obvious from symptoms alone

Thyroid-related symptoms have many possible causes, and thyroid-stimulating hormone (TSH) alone is not a sensitive indicator of iodine deficiency. Suspected deficiency or thyroid disease belongs in the appropriate healthcare context rather than simply increasing iodine supplements.

Safety: why more is not automatically better

The European adult tolerable upper intake level for iodine is 600 µg/day from total intake. Both insufficient and excessive iodine can affect thyroid function. People with thyroid disorders, people taking thyroid medicines and those considering high-dose iodine products should use particular caution and seek appropriate professional guidance.

Potassium iodide vs kelp

Potassium iodide is a defined iodine salt that allows a precise iodine dose to be formulated. Kelp-based products use seaweed as the source and should still state a defined amount of iodine on the label. A product containing 30 mg or 300 mg of kelp does not provide 30 or 300 mg of iodine.

How much iodine should you compare?

The EU nutrient reference value is 150 µg. Many standard iodine supplements provide this amount in one tablet, which makes form and formulation more useful differentiators than simply choosing a larger number.

Compare iodine source and daily amount →

Iodine in thyroid-support formulas

Iodine is sold both as a single-mineral supplement and as part of broader thyroid-focused formulas. Combination products may also contain selenium, zinc or other micronutrients. The useful comparison is not the number of ingredients but whether each nutrient and its daily amount is clearly declared.

What should you compare?

Iodine per day

Compare the recommended daily serving in micrograms.

Iodine source

Potassium iodide, kelp/seaweed or a combination.

Kelp amount vs iodine amount

Keep the seaweed weight separate from the actual iodine provided.

Other active ingredients

Some iodine products are simple single-mineral tablets; others are multinutrient formulas.

Format & vegan suitability

Tablets are common. Kelp itself can be plant/seaweed-derived, but the full formulation still determines vegan suitability.

Health information: Iodine directly affects thyroid-hormone production. This guide is general information, not advice to self-treat thyroid disease or change thyroid medication.

Product comparison

Compare iodine supplements

Compare iodine per day, serving, iodine per unit, source, kelp or source detail, format and vegan suitability.

Compare iodine µg — not kelp mg. Most standard products here provide 150 µg iodine, so source, serving and formulation become the useful differentiators. Iodine EU Nutrient Reference Value (NRV): 150 µg for adult labelling; it is a labelling reference, not a personal dose recommendation.

Default order: standard labelled daily iodine amount, then alphabetically. A larger iodine dose is not treated as a higher-quality product.

Product	Iodine / day	Recommended serving	Iodine / unit	Iodine source	Kelp / source detail	Format	Vegan
GSE Iodine Compact OrganicView product ↗	150 µg	1 tablet daily	150 µg	Organic Ascophyllum nodosum seaweed	Organic seaweed powder	Tablet	Yes
Lamberts IodineView product ↗	150–300 µg	1–2 tablets daily	150 µg	Potassium iodide	—	Tablet	Yes
Vegavero Natural Iodine OrganicView product ↗	150 µg	1 capsule daily	150 µg	Organic Scottish kelp (Ascophyllum nodosum)	231 mg kelp / capsule	Vegan capsule	Yes
Viridian Organic KelpView product ↗	200 µg	1 capsule daily with food	200 µg	Organic kelp	286 mg organic kelp / capsule	Plant-cellulose capsule	Yes
NOW Foods Kelp 325 µgView product ↗	325 µg	1 capsule daily with a meal	325 µg	Organic kelp (Laminaria spp.)	100 mg kelp / capsule	Veg capsule	Yes

Why the source column matters: a kelp tablet can contain tens or hundreds of milligrams of seaweed while providing only 150 µg iodine. The iodine dose is the comparable nutrient amount.

Safety: The adult European Tolerable Upper Intake Level (UL) is 600 µg/day from total intake. Thyroid disease, thyroid medicines and high-dose iodine deserve professional guidance.

EU health claim details

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Authorised health claims

A quick consumer view — full regulatory list available below

● Iodine contributes to the normal production of thyroid hormones and normal thyroid function.Thyroid function · General population

Claim type
Health functions (Article 13)

Condition of use
The claim may be used only for food which is at least a source of iodine.

What does “source of” usually mean?
General food: 22.5 µg / 100 g or 100 ml
Beverage: 11.25 µg / 100 ml
Single-portion pack: 22.5 µg per portion
Calculated from the EU NRV significant-amount reference. Claim-specific conditions take precedence.