Iodine (Potassium Iodide)

Essential mineral form providing stable iodine for optimal thyroid function and metabolism

Scientific namePotassium Iodide FormulaKI Molecular weight166 g/mol CAS7681-11-0

95 absorption score

6 safety / 10

8 USD per month

23 elemental potassium %

6 documented interactions

Check it against something

Evidence level A

Iodine (Potassium Iodide) with:

94 out of 100

Works better together Take together — same timing window amplifies the synergy.

Check it against your whole stack →

What it does

mechanism and evidence for each claim

Optimal thyroid function

Essential for thyroid hormone T3 and T4 production

Required component of thyroid hormones thyroxine and triiodothyronine Evidence A-grade 4-8 weeks

Enhanced metabolism and energy

Supports metabolic rate and energy production

Thyroid hormones regulate basal metabolic rate Evidence A-grade 4-12 weeks

Brain development and cognitive function

Critical for normal brain development and function

Thyroid hormones essential for neurological development Evidence A-grade Critical during pregnancy/childhood

Breast and reproductive health

Important for breast tissue and reproductive function

Iodine concentrated in breast and reproductive tissues Evidence B-grade 8-16 weeks

Detoxification support

May help remove toxic halogens like bromide and fluoride

Iodine can displace other halogens from tissue Evidence C-grade 4-12 weeks

Others take these for the same thing

Same goal, different mechanism — check any of them against this one

Melatonin Sleep support & circadian rhythm 0.5-3mg A 50% Ashwagandha Stress management & energy 300-600mg A 75% Vitamin B12 (Cyanocobalamin) Energy & nerve support 250-1000 mcg A 70% Coenzyme Q10 (CoQ10) Heart health & cellular energy 100-200mg A 10% Phosphorus Bone health & energy metabolism 700-1250mg A 80% Vitamin B3 (Niacinamide) Energy & skin health (no flush) 100-1000 mg A 88%

Every pair we checked

12 combinations scored by the engine

Iodine (Potassium Iodide) + Caffeine No documented interaction either way No known interaction 70

Iodine (Potassium Iodide) + Creatine Monohydrate No documented interaction either way No known interaction 70

Iodine (Potassium Iodide) + Vitamin D3 No documented interaction either way No known interaction 70

Iodine (Potassium Iodide) + Calcium Carbonate No documented interaction either way No known interaction 70

Iodine (Potassium Iodide) + Whey Protein No documented interaction either way No known interaction 70

Iodine (Potassium Iodide) + Lactase No documented interaction either way No known interaction 70

Iodine (Potassium Iodide) + Bovine Collagen No documented interaction either way No known interaction 70

Iodine (Potassium Iodide) + DHA No documented interaction either way No known interaction 70

Iodine (Potassium Iodide) + Turmeric No documented interaction either way No known interaction 70

Iodine (Potassium Iodide) + Zinc Gluconate Important for thyroid hormone conversion Works better together 78

Iodine (Potassium Iodide) + L-Tyrosine Amino acid component of thyroid hormones Works better together 82

Iodine (Potassium Iodide) + Selenium (Thyroid Support) Essential for thyroid hormone metabolism Works better together 94

Dosage

With food

Daily150-300 mcg

Maintenance150-225 mcg

Therapeutic300-600 mcg (medical supervision)

Pregnancy lactation220-290 mcg

Upper limit1100 mcg daily

Upper limit 1100 mcg NIH ODS

Before you take it

VeganYes

When to expect it

First Effects2-4 weeks for metabolic improvements

Peak Benefits8-16 weeks for thyroid optimization

Deficiency DevelopmentWeeks to months depending on stores

Toxicity OnsetDays to weeks with very high doses

How to measure it

$80-200

MarkerUrinary iodine, TSH, T3, T4, or thyroid antibodies

OptimalUrinary iodine: 100-299 μg/L, TSH: 0.5-2.5 mIU/L

Deficient belowUrinary iodine: <100 μg/L

FrequencyEvery 6-12 months if supplementing or have thyroid issues

What people actually reported to the FDA

CAERS, 35 reports naming it as the suspect

Most reported effects

Hyperthyroidism 5

Dyspnoea 4

Diarrhoea 4

Nausea 3

Local swelling 3

Named as the suspect 35 reports of 57 that mention it at all

Serious outcome 85% hospitalisation, emergency room or worse

Other Serious or Important Medical Event26

Hospitalization8

Visited a Health Care Provider8

Reports are voluntary and unverified — they record what someone experienced while taking something, not what the compound caused. Counts skew towards products people take a lot of, and a serious outcome is more likely to be reported than a mild one, so these are not rates. How we filter them →

What actually reaches you

The label counts the carrier, your body does not

Elemental potassium 23.6% of 166 g/mol

Absorption Very high 95 of 100 · best absorbed form of this compound

Delivered daily 0.1 mg

Cost per 1 mg delivered $5.29 comparative — uses the absorption score, not a measured percentage

A 500 mg capsule of Iodine (Potassium Iodide) contains 118 mg of potassium. How much of that crosses into your blood is not measured for this form — the absorption score ranks it against other forms, it is not a share of the dose. How this is calculated →

Works better with

3 documented

Selenium

Essential for thyroid hormone metabolism

Required for deiodinase enzymes that activate thyroid hormones · level A

Tyrosine

Amino acid component of thyroid hormones

Iodine attached to tyrosine forms thyroid hormones · level A

Zinc

Important for thyroid hormone conversion

Required for T4 to T3 conversion · level B

What not to take with Iodine (Potassium Iodide)

3 documented

Bromide Fluoride

Halogen competition displaces iodine

Other halogens compete for same receptors · major significance

Goitrogens Soy Cruciferous

Interfere with iodine utilization

Block thyroid peroxidase and hormone synthesis · moderate significance

Calcium Iron High

May reduce iodine absorption

Mineral competition for absorption · mild significance

Medication interactions

Discuss these with a pharmacist before combining

lithium Major

Both can affect thyroid function

What to do: Monitor thyroid function closely

ace-inhibitors Moderate

May increase potassium levels

What to do: Monitor potassium levels

thyroid-medications Major

May affect thyroid hormone levels

What to do: Monitor thyroid function, adjust medications

Available forms

bioavailability compared

Potassium Iodide 95

Potassium Iodide: Stable form, Well-absorbed, Inexpensive, Established safety

Food sources

before you supplement

Seaweed (kelp, nori) 150-2900 mcg per serving · 90

Iodized salt 76 mcg per 1/4 teaspoon · 95

Seafood (cod, shrimp) 90-130 mcg per 100g · 85

Dairy products 56-90 mcg per cup · 80

Too little

deficiency signs

Hypothyroidism and goiter
Fatigue and weight gain
Cold intolerance and dry skin
Hair loss and brittle nails
Depression and cognitive impairment
Cretinism in severe deficiency (children)
Increased cancer risk (breast, thyroid)

Too much

toxicity signs

Acute: burning mouth, nausea, vomiting
Chronic: thyroid dysfunction
Hyperthyroidism or hypothyroidism
Goiter formation
Thyroiditis and inflammation
Skin rash and acne-like lesions

Who benefits most

iodine-deficient-regions

Essential for those in areas with low soil iodine

150-300 mcg daily

pregnant-breastfeeding-women

Critical for fetal and infant brain development

220-290 mcg daily

hypothyroid-subclinical

May help optimize thyroid function

150-300 mcg daily (with monitoring)

low-salt-diet

May not get adequate iodine from iodized salt

150-225 mcg daily

vegan-vegetarian

May have lower iodine intake without dairy/seafood

150-225 mcg daily

Where to buy it

compare forms first

Look for Iodine (Potassium Iodide) at 150-300 mcg per serving. The form that matters here is Potassium Iodide.

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How it works

Essential component of thyroid hormones T3 and T4
Concentrated by sodium-iodide symporter in thyroid
Required for thyroid peroxidase enzyme function
Regulates gene expression through thyroid hormone receptors
Essential for normal growth and development
Involved in immune system regulation

Key findings

what the evidence supports

Essential for thyroid hormone production (established science)
Critical for brain development during pregnancy and childhood
Deficiency is major global health problem
Iodization programs have dramatically reduced deficiency diseases

Sources: NIH Examine.com · data reviewed 2026-08-02

Compiled by Denis, who maintains this database and holds no medical qualification — every figure here is sourced or derived, never asserted. How we calculate it →

Common questions

What are the benefits of Iodine (Potassium Iodide)?

Documented effects: Optimal thyroid function; Enhanced metabolism and energy; Brain development and cognitive function; Breast and reproductive health. Essential for thyroid hormone T3 and T4 production

How much Iodine (Potassium Iodide) should you take per day?

The common daily range is 150-300 mcg. By goal — maintenance: 150-225 mcg; therapeutic: 300-600 mcg (medical supervision); pregnancy lactation: 220-290 mcg; upper limit: 1100 mcg daily.

When is the best time to take Iodine (Potassium Iodide)?

With food. First effects are typically reported within 2-4 weeks for metabolic improvements.

What are the side effects of Iodine (Potassium Iodide)?

At excessive doses: Acute: burning mouth, nausea, vomiting, Chronic: thyroid dysfunction, Hyperthyroidism or hypothyroidism, Goiter formation, Thyroiditis and inflammation. Safety rating at normal doses is 6 out of 10.

What should you not take with Iodine (Potassium Iodide)?

Separate it from Bromide Fluoride, Goitrogens Soy Cruciferous, Calcium Iron High by two to four hours. Halogen competition displaces iodine

Does Iodine (Potassium Iodide) interact with medications?

Documented interactions with lithium, ace-inhibitors, thyroid-medications. Discuss these with a pharmacist before combining.

How much Iodine (Potassium Iodide) is too much?

The tolerable upper intake level is 1100 mcg per day for adults, per NIH ODS. Above that, the risk of adverse effects rises: Acute: burning mouth, nausea, vomiting, Chronic: thyroid dysfunction, Hyperthyroidism or hypothyroidism.

How do you know if you need Iodine (Potassium Iodide)?

The marker is Urinary iodine, TSH, T3, T4, or thyroid antibodies, optimal range Urinary iodine: 100-299 μg/L, TSH: 0.5-2.5 mIU/L. Common deficiency signs: Hypothyroidism and goiter, Fatigue and weight gain, Cold intolerance and dry skin, Hair loss and brittle nails.

Taken for

62 Energy & Metabolism

Vitamin B12 (Methylcobalamin) · Ashwagandha · Vitamin B12 (Cyanocobalamin)

27 Hormones

Melatonin · Vitamin B6 (Pyridoxine HCl) · Vitamin B6 (P5P)