Iodine: Daily Needs Explained
Many multivitamins and pregnancy formulas list iodine, often as potassium iodide or kelp, in small microgram amounts. This guide explains what iodine does, the 150 µg NRV, the EFSA upper limit, why seaweed products vary so much, and who should speak to a doctor before adding more.
What iodine is
Iodine is an essential trace mineral. The body uses it to make thyroid hormones, and most of the body's iodine is held in the thyroid gland in the neck. Because the body cannot make iodine, it has to come from food, iodised salt or supplements.
The EU authorises five iodine claims, covering the normal production of thyroid hormones and normal thyroid function, energy-yielding metabolism, the nervous system, cognitive function and skin. The exact wording is in the authorised claims box below. Like several trace minerals, iodine works within a range: both too little and too much can affect how the thyroid works.
Forms you'll see on labels
| Form | What to know |
|---|---|
| Potassium iodide | The most common form in multivitamins and pregnancy supplements. The amount of potassium it adds is tiny. |
| Potassium iodate | Often used to iodise salt, and found in some supplements. |
| Sodium iodide | Used in some tablets and liquid products. |
| Kelp or seaweed extract | A natural iodine source. Seaweed iodine content varies enormously; the NIH reports commercial seaweeds ranging from about 16 to 2,984 µg per gram. Choose products that state a measured iodine amount per serving. |
| Iodised salt | Not a supplement, but an important everyday source in many countries. |
Iodine usually comes as part of a multivitamin or a pregnancy formula rather than on its own. See options in our minerals collection.
How much iodine?
- NRV (EU label reference): 150 µg a day. A product with at least 22.5 µg per daily portion (15% of NRV) may use the authorised claims.
- Upper limit: 600 µg a day from all sources for adults (EFSA). The NHS says 500 µg a day or less from supplements is unlikely to cause harm.
- Pregnancy and breastfeeding: needs rise. The NIH gives 220 µg a day in pregnancy and 290 µg a day when breastfeeding; pregnancy multivitamins are formulated with this in mind.
- Typical supplements: 75 to 150 µg per serving in multivitamins; some gummies contain less.
Food sources include fish and seafood, seaweed, milk, yoghurt and cheese, eggs and iodised salt. Plant foods vary with the iodine in the soil. People who avoid dairy and seafood, or who use only non-iodised or "gourmet" salts such as sea salt or Himalayan salt, may get less iodine.
Who should check with a doctor or pharmacist first
- Anyone with a thyroid condition, or who has had thyroid surgery, should not take extra iodine or kelp unless their doctor advises it.
- Antithyroid medicines such as methimazole: high iodine intakes can interfere with them.
- ACE inhibitors and potassium-sparing diuretics: products that use potassium iodide add a little potassium; with high doses, ask your doctor.
- Pregnancy and breastfeeding: iodine needs rise, but choose a product made for this stage and follow your doctor's or midwife's advice rather than adding kelp.
- Children: check the age range on the pack and ask a doctor or pharmacist before giving an iodine-containing supplement.
How to read an iodine label
- Check the unit: iodine is listed in µg (or mcg). 150 µg is 0.15 mg.
- Look for a measured amount: "Iodine 150 µg (from kelp)" is more useful than "kelp powder 200 mg" with no iodine figure.
- %NRV: 150 µg is 100% NRV; 80 µg is about 53% and 42 µg is 28%.
- Per serving vs per gummy: two gummies may make one serving.
- Add up products: a multivitamin plus a hair formula plus a kelp tablet can add up faster than expected.
Bahrain & GCC notes
Seafood is a regular part of many Gulf diets and adds iodine, and iodised salt is widely sold; look for "iodised" on the pack. If you prefer sea salt or specialty salts, it is worth checking whether they are iodised. Store supplements in a cool, dry place, as heat and humidity can affect tablets and gummies. Compare iodine-containing formulas in the minerals range.
- Iodine contributes to the normal production of thyroid hormones and normal thyroid function
- Iodine contributes to normal energy-yielding metabolism
- Iodine contributes to normal functioning of the nervous system
- Iodine contributes to normal cognitive function
- Iodine contributes to the maintenance of normal skin
Applies to products that provide at least 15% of the NRV per daily portion (a 'source of' the nutrient).
Products with Iodine
Always read the label and check the amount per serving.
FOLIGAINFoligain Stimulating Supplement, 60 TabletsBHD24.750
T-RQT-RQ Multi-Vitamin Complete Adult, 60 GummiesBHD7.920
AMERIXAMERIX Hair Health Vitamin, 60 GummiesBHD9.550
DéléBooDéléBoo Multivitamin Beans with Zinc and Iodine (Green Apple), 90 GummiesBHD9.680Frequently asked questions
Do I need an iodine supplement?
Many people get enough iodine from seafood, dairy, eggs and iodised salt. Needs rise in pregnancy and breastfeeding, so ask your doctor which product suits you.
Is kelp a good way to get iodine?
Kelp contains iodine, but the amount varies widely between products. Choose one that states a measured iodine amount per serving, and avoid kelp if you have a thyroid condition unless your doctor agrees.
How much iodine is too much?
EFSA sets the adult upper limit at 600 µg a day from all sources. Very high intakes over time can change how the thyroid works.
Can I take iodine if I have a thyroid condition?
Only if your doctor advises it. Extra iodine can interfere with thyroid medicines and with some thyroid conditions.
Is sea salt a source of iodine?
Not necessarily. Unless the pack says iodised, sea salt and specialty salts may contain little iodine.
