About
What it is and where it shows up.
Potassium iodide is an inorganic salt used as a source of dietary iodine, primarily added to table salt to prevent iodine deficiency disorders such as goiter and hypothyroidism. It is also used as a nutritional fortifier in infant formulas and select processed foods.
Safety summary
The regulatory and scientific consensus.
Potassium iodide is well-tolerated at nutritional levels in the general adult population and is GRAS-affirmed by the FDA at a maximum of 0.01% in table salt. Excessive chronic intake can cause thyroid disruption including iodide goiter and hypothyroidism, especially in iodine-sufficient regions; the EFSA-established adult tolerable upper level for iodine is 600 µg/day. Individuals with pre-existing thyroid conditions such as Graves' disease, multinodular goiter, or autoimmune thyroiditis face elevated risk from high or prolonged doses.
Regulatory landscape
What food-safety regulators have decided.
| Jurisdiction | Status | Note |
|---|---|---|
| EFSA (European Food Safety Authority) (European Union) | Approved | Authorised as a nutritional feed additive (compound of trace elements, category 3b201) under Commission Regulation (EU) 2015/861 for all animal species. For human foods, potassium iodide is permitted for salt iodisation under national laws of EU member states; 10 EU member states permit potassium iodide (KI) specifically for salt iodisation. Tolerable upper iodine intake level for adults set at 600 µg/day by EFSA.source |
| FSSAI (Food Safety and Standards Authority of India) (India) | Approved | Mandatory iodisation of common white table salt is required under FSS (Prohibition and Restriction on Sales) Regulations 2011, Sub-regulation 2.3.12. Traditional salts (rock salt, black salt, Himalayan pink salt) are exempt from mandatory iodisation. Governed also by Food Safety and Standards (Fortification of Foods) Regulations, 2018.source |
| FDA (Food and Drug Administration) (United States) | Approved | GRAS-affirmed under 21 CFR 184.1634; permitted in table salt as iodine source at a maximum of 0.01%; also permitted as a food additive under 21 CFR 172.375 for use in certain coatings and food contact applications. Salt bearing the additive must be labeled 'iodized salt'.source |
Who should approach with care
Whose guidance would steer them away.
Thyroid Disease — Individuals with Graves' disease, multinodular goiter, or autoimmune thyroiditis are at increased risk of thyroid dysfunction (iodide goiter, thyrotoxic crisis, hypothyroidism) from high or prolonged iodide intake, as noted in FDA guidance.
Infants — EFSA notes that the tolerable upper iodine level for toddlers (200 µg/day) can be exceeded by a factor of up to 4 when livestock are fed at maximum authorised iodine levels, requiring monitoring of iodine exposure in young children.
Pregnancy — Iodine deficiency during pregnancy can cause cretinism and developmental delays in offspring, but repeat high-dose potassium iodide administration also raises specific safety concerns in pregnant women, as noted in FDA radiation emergency guidance.
Lactation — Repeat administration of high-dose potassium iodide raises particular safety concerns in lactating women, as flagged in FDA guidance on thyroid blocking agents.
Kidney Disease — Impaired renal clearance in individuals with kidney disease may lead to accumulation of iodide, increasing the risk of thyroid dysfunction from excess iodine; medical supervision is advisable.
Research citations
The sources behind this verdict.
- 1WHO. JECFA 37th Meeting: Confirmation of potassium iodide as a source of dietary iodine. apps.who.int
- 2FDA. Potassium Iodide as a Thyroid Blocking Agent in Radiation Emergencies (FDA Guidance). fda.gov
- 3PubMed. Vast gap in iodization from production to plate — Hurdles in achieving Universal Salt Iodization in India, 2022. pmc.ncbi.nlm.nih.gov
- 4PubMed. FDA regulations regarding iodine addition to foods and labeling of foods containing added iodine, 2016. pmc.ncbi.nlm.nih.gov
- 5other. Commission Regulation (EU) 2015/861 of 3 June 2015 concerning the authorisation of potassium iodide and calcium iodate anhydrous as feed additives for all animal species, 2015. eur-lex.europa.eu
- 6EFSA. Scientific Opinion on the safety and efficacy of iodine compounds (E2) as feed additives for all animal species: calcium iodate anhydrous and potassium iodide, 2013.
Independently researched6 citations