How much iodine do adults need?

Adults need 150 micrograms a day, or 220 in pregnancy (US, NIH). In the UK: 140 micrograms a day (NHS).

Which foods have iodine?

Fish, seaweed, shrimp, milk and yogurt, eggs, iodised salt.

Iodine: what it does and how much you need

Iodine is used to make thyroid hormones, which control metabolism and matter for bone and brain development in pregnancy and infancy. Adults need 150 micrograms a day, or 220 in pregnancy, and the upper limit is 1,100 micrograms a day.

Checked 28 September 2026 with Supplement Check's data from the NIH fact sheet and NHS guidance · Adults only

General information, not medical advice. Check with a doctor or pharmacist before taking a supplement, especially if you are pregnant or breastfeeding, take any medicine, or are under 18.

In the UK

In the UK, adults need 140 micrograms a day, and the NHS says up to 500 micrograms (0.5 milligrams) a day from supplements is unlikely to cause harm.

How much you need and the upper limit

	US (NIH)	UK (NHS)
Adults need	150 micrograms a day, or 220 in pregnancy	140 micrograms a day
Upper limit	1,100 micrograms a day	Up to 500 micrograms (0.5 milligrams) a day from supplements

The UK figure is the amount the NHS says is unlikely to cause harm. Figures are for adults.

Food sources

Fish
Seaweed
Shrimp
Milk and yogurt
Eggs
Iodised salt

Dose questions

Is 1000 mcg of iodine too much?

Quick answers

What does iodine do?: Iodine is used to make thyroid hormones, which control metabolism and matter for bone and brain development in pregnancy and infancy.
How much iodine do adults need?: Adults need 150 micrograms a day, or 220 in pregnancy (US, NIH). In the UK: 140 micrograms a day (NHS).
What is the upper limit for iodine?: US: 1,100 micrograms a day. UK (NHS): up to 500 micrograms (0.5 milligrams) a day from supplements is unlikely to cause harm.
Which foods have iodine?: Fish, seaweed, shrimp, milk and yogurt, eggs, iodised salt.

Sources

NIH Office of Dietary Supplements fact sheet
https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/
NHS vitamins and minerals guidance
https://www.nhs.uk/conditions/vitamins-and-minerals/iodine/

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