Iodine (Thyroid Support)

Essential trace mineral required for thyroid hormone synthesis, supporting thyroid function, metabolism regulation, and hormonal balance

Scientific nameIodine FormulaI Molecular weight126.9 g/mol CAS7553-56-2

95 absorption score

7 safety / 10

20 USD per month

100 elemental iodine %

5 documented interactions

Check it against something

Evidence level A

Iodine (Thyroid Support) with:

94 out of 100

Works better together Compatible. Timing differs, so follow each supplement's own window.

Check it against your whole stack →

What it does

mechanism and evidence for each claim

Essential thyroid hormone synthesis

Required for production of T3 and T4 thyroid hormones

Incorporated into tyrosine residues to form thyroid hormones Evidence A-grade 2-8 weeks

Metabolic rate regulation and energy enhancement

Supports healthy metabolic rate and energy production

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

Cognitive function and brain health

Supports cognitive function, memory, and brain development

Thyroid hormones are essential for brain development and function Evidence A-grade 6-16 weeks

Temperature regulation and thermogenesis

Helps maintain body temperature and thermogenic processes

Thyroid hormones regulate body temperature and heat production Evidence A-grade 2-8 weeks

Growth and development support

Essential for normal growth and developmental processes

Thyroid hormones regulate growth hormone effects and development Evidence A-grade 8-24 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 (Thyroid Support) + Caffeine No documented interaction either way No known interaction 70

Iodine (Thyroid Support) + Creatine Monohydrate No documented interaction either way No known interaction 70

Iodine (Thyroid Support) + Vitamin D3 No documented interaction either way No known interaction 70

Iodine (Thyroid Support) + Calcium Carbonate No documented interaction either way No known interaction 70

Iodine (Thyroid Support) + Whey Protein No documented interaction either way No known interaction 70

Iodine (Thyroid Support) + Lactase No documented interaction either way No known interaction 70

Iodine (Thyroid Support) + Bovine Collagen No documented interaction either way No known interaction 70

Iodine (Thyroid Support) + DHA No documented interaction either way No known interaction 70

Iodine (Thyroid Support) + Turmeric No documented interaction either way No known interaction 70

Iodine (Thyroid Support) + Zinc Gluconate Improved thyroid hormone synthesis and metabolism Works better together 78

Iodine (Thyroid Support) + L-Tyrosine Enhanced thyroid hormone synthesis and production Works better together 82

Iodine (Thyroid Support) + Selenium (Thyroid Support) Enhanced thyroid hormone metabolism and antioxidant protection Works better together 94

Dosage

Morning with food

Daily150-300mcg

Thyroid support150-300mcg daily

Metabolic health150-250mcg daily

Pregnancy support220-290mcg daily

Deficiency correction150-400mcg daily

Upper limit 1100 mcg NIH ODS

When to expect it

First Effects2-4 weeks for initial thyroid function improvements

Peak Benefits8-16 weeks for sustained thyroid and metabolic benefits

Deficiency DevelopmentCommon in areas with low soil iodine content

Toxicity OnsetRisk increases with doses above 1000mcg daily

How to measure it

$100-200

MarkerTSH, Free T3, Free T4, thyroid antibodies, urinary iodine

OptimalNormal TSH 0.5-4.5 mIU/L, adequate urinary iodine 100-199 mcg/L

Deficient belowElevated TSH, low iodine excretion <100 mcg/L

FrequencyEvery 3-6 months for thyroid monitoring, annually for iodine status

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 iodine 100% of 126.9 g/mol

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

Delivered daily 0.2 mg

Cost per 1 mg delivered $3.12 comparative — uses the absorption score, not a measured percentage

A 500 mg capsule of Iodine (Thyroid Support) contains 500 mg of iodine. 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

Enhanced thyroid hormone metabolism and antioxidant protection

Selenium required for thyroid hormone deiodinase enzymes · level A

Tyrosine

Enhanced thyroid hormone synthesis and production

Tyrosine provides amino acid backbone for thyroid hormones · level A

Zinc

Improved thyroid hormone synthesis and metabolism

Zinc supports thyroid hormone production and conversion · level B

What not to take with Iodine (Thyroid Support)

2 documented

Goitrogenic Foods

Cruciferous vegetables may interfere with iodine utilization

Goitrogens can block iodine uptake by thyroid gland · moderate significance

Fluoride Chlorine

Halides compete with iodine for thyroid uptake

Chemical competition for thyroid transport mechanisms · moderate significance

Medication interactions

Discuss these with a pharmacist before combining

thyroid-medications Moderate

May affect thyroid medication dosing requirements

What to do: Monitor thyroid function closely with thyroid medications

lithium Moderate

Lithium may enhance iodine's thyroid-suppressing effects

What to do: Monitor thyroid function with lithium therapy

Available forms

bioavailability compared

Potassium Iodide (Most Common Supplemental Form) 95

Potassium Iodide (Most Common Supplemental Form): Essential thyroid function, Strong research, Well absorbed, Cost-effective

Food sources

before you supplement

Seaweed (kelp, nori) 1000-8000mcg per 100g · 85

Fish and seafood 50-150mcg per 100g · 90

Iodized salt 76mcg per gram · 95

Dairy products 10-50mcg per 100g · 85

Too little

deficiency signs

Iodine deficiency symptoms:
Hypothyroidism and reduced thyroid hormone production
Goiter (enlarged thyroid gland)
Fatigue, weight gain, and slow metabolism
Cold intolerance and low body temperature
Cognitive impairment and brain fog
Hair loss and dry skin

Too much

toxicity signs

Iodine excess symptoms:
Hyperthyroidism and overactive thyroid
Rapid heart rate and anxiety
Weight loss and increased appetite
Heat intolerance and excessive sweating
Thyroid inflammation and autoimmune reactions
Should be monitored with thyroid function tests

Who benefits most

thyroid-function-support

Essential thyroid hormone production and glandular health

150-300mcg daily

metabolic-health-enhancement

Metabolic rate regulation and energy production support

150-250mcg daily

pregnancy-development-support

Essential for fetal brain development and maternal thyroid health

220-290mcg daily

cognitive-brain-function

Brain health and cognitive function optimization

150-250mcg daily

iodine-deficient-regions

Essential supplementation in areas with low dietary iodine

150-300mcg daily

Where to buy it

compare forms first

Look for Iodine (Thyroid Support) at 150-300mcg per serving. The form that matters here is Potassium Iodide (Most Common Supplemental Form).

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What else affects it

Beyond other supplements

Goitrogenic foods

Cruciferous vegetables may interfere with iodine utilization

Goitrogens can block iodine uptake by thyroid gland

How it works

Essential component of thyroid hormones T3 (triiodothyronine) and T4 (thyroxine)
Incorporated into tyrosine residues by thyroid peroxidase enzyme
Enables thyroid hormone synthesis and release into circulation
Regulates basal metabolic rate through thyroid hormone action
Supports brain development and cognitive function via thyroid hormones
Essential for normal growth and developmental processes

Key findings

what the evidence supports

Extensive evidence for essential thyroid function and hormone synthesis
Strong research on metabolic rate regulation and energy production
Critical for brain development and cognitive function
Important to balance intake - both deficiency and excess are harmful

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 (Thyroid Support)?

Documented effects: Essential thyroid hormone synthesis; Metabolic rate regulation and energy enhancement; Cognitive function and brain health; Temperature regulation and thermogenesis. Required for production of T3 and T4 thyroid hormones

How much Iodine (Thyroid Support) should you take per day?

The common daily range is 150-300mcg. By goal — thyroid support: 150-300mcg daily; metabolic health: 150-250mcg daily; pregnancy support: 220-290mcg daily; deficiency correction: 150-400mcg daily.

When is the best time to take Iodine (Thyroid Support)?

Morning with food. First effects are typically reported within 2-4 weeks for initial thyroid function improvements.

What are the side effects of Iodine (Thyroid Support)?

At excessive doses: Iodine excess symptoms:, Hyperthyroidism and overactive thyroid, Rapid heart rate and anxiety, Weight loss and increased appetite, Heat intolerance and excessive sweating. Safety rating at normal doses is 7 out of 10.

What should you not take with Iodine (Thyroid Support)?

Separate it from Goitrogenic Foods, Fluoride Chlorine by two to four hours. Cruciferous vegetables may interfere with iodine utilization

Does Iodine (Thyroid Support) interact with medications?

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

How much Iodine (Thyroid Support) 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: Iodine excess symptoms:, Hyperthyroidism and overactive thyroid, Rapid heart rate and anxiety.

How do you know if you need Iodine (Thyroid Support)?

The marker is TSH, Free T3, Free T4, thyroid antibodies, urinary iodine, optimal range Normal TSH 0.5-4.5 mIU/L, adequate urinary iodine 100-199 mcg/L. Common deficiency signs: Iodine deficiency symptoms:, Hypothyroidism and reduced thyroid hormone production, Goiter (enlarged thyroid gland), Fatigue, weight gain, and slow metabolism.

Taken for

62 Energy & Metabolism

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

27 Hormones

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