Iodine
Iodine is an essential mineral — a trace element used by the thyroid gland to make thyroid hormones. 59 peer-reviewed studies are available in our database. Common forms include Potassium Iodide, Kelp, Sodium Iodide.
Content reviewed by Zynava Research Team · Last updated February 2026 · Editorial policy
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Explore iodine supplements and browse options based on ingredient research.
What Is Iodine?
A trace element used by the thyroid gland to make thyroid hormones.
Key fact: Kelp is a natural iodine source; iodide salts are common.
Iodine Supplement Forms
Iodine is available in several supplemental forms: Potassium Iodide, Kelp, Sodium Iodide. Kelp is a natural iodine source; iodide salts are common.
Explore Iodine Supplements
Use our research tool to explore iodine supplements and see what studies have examined.
Research Studies on Iodine
Our database contains 59 peer-reviewed studies examining iodine. Below are selected recent studies:
Health Goals Associated with Iodine
Research has examined iodine in relation to several health areas:
Related Supplements
Frequently Asked Questions About Iodine
What is Iodine?
A trace element used by the thyroid gland to make thyroid hormones.
What are the different forms of Iodine?
Iodine is available in several supplemental forms including Potassium Iodide, Kelp, Sodium Iodide. Kelp is a natural iodine source; iodide salts are common.
What health goals is Iodine associated with?
Research has examined iodine in relation to several health areas including thyroid health. The best supplement depends on individual factors — consult a healthcare professional for personalized guidance.
Natural Food Sources of Iodine
While supplementation can be a convenient way to increase iodine intake, many people prefer to start with dietary sources. Understanding which foods are naturally rich in iodine can help you make informed decisions about whether supplementation is right for you.
- Seaweed (nori, kelp) — One of the most concentrated sources — amounts can vary widely by type and serving size
- Iodized salt — A predictable dietary source when used regularly (not all salts are iodized)
- Cod — White fish often provides meaningful iodine per serving
- Dairy products — Milk and yogurt can contribute iodine depending on farming practices
- Eggs — Egg yolks provide modest iodine amounts
Dietary Context
Iodine is a trace mineral essential for thyroid hormone production. Because iodine content depends heavily on geography and food systems, intake can vary a lot between diets and regions. Many people get most of their iodine from iodized salt and seafood.
Absorption: Food vs. Supplements
Iodine is generally absorbed efficiently. The bigger issue is consistency: some diets use mostly non-iodized specialty salts, and some people avoid salt entirely, which can reduce iodine intake unless seafood or other sources are regular.
Practical Tips
- If you use salt, check whether it is iodized — many sea salts are not
- Seaweed can be very potent, so small consistent servings tend to be better than occasional large amounts
- If you avoid seafood and dairy, you may need a more intentional iodine strategy
How to Take Iodine
To optimize the benefits of iodine supplementation, consider these practical guidelines on timing, food pairing, and potential interactions based on available research.
Best time to take: Morning with a meal
With or Without Food
Can be taken with or without food. Taking with a meal may improve tolerance.
How Often
Once daily. The RDA is 150 mcg for adults. Pregnant women need 220 mcg and breastfeeding women need 290 mcg.
Practical Tips
- Iodized salt is the primary dietary source for most people — check if your salt is iodized
- Seaweed (kelp) can contain extremely variable and potentially excessive amounts of iodine
- If you eat a lot of cruciferous vegetables (broccoli, cabbage), adequate iodine is particularly important
Important Interactions
- May interact with thyroid medications (levothyroxine) — consult your healthcare provider
- Excess iodine can worsen thyroid conditions in susceptible individuals
- Amiodarone contains significant iodine — supplementation should be discussed with a cardiologist
This is not an exhaustive list of interactions. Always consult a healthcare provider or pharmacist about potential interactions with your specific medications and health conditions.
Where to Find Iodine Supplements
Ready to explore iodine supplements? These reputable retailers offer a range of options with customer reviews and competitive pricing. Always compare products by checking the amount of active ingredient per serving.
How to Choose a Quality Iodine Supplement
- Check for third-party testing certifications (USP, NSF, or ConsumerLab) which verify potency and purity
- Compare cost per serving rather than total package price for accurate value comparison
- Read the supplement facts panel to verify the amount of active ingredient per serving
- Look for products with minimal unnecessary fillers, binders, or artificial additives
To explore supplements by ingredient or health goal, try our AI Supplement Advisor.
Research Highlights: Iodine
Scientific inquiry into iodine has produced 3 clinical trials, 2 meta-analysiss, 1 review over the period 2023 to 2025. The following highlights are drawn from peer-reviewed publications in our research database. Study results reflect controlled conditions and may differ from real-world outcomes.
Modern challenges of iodine nutrition: vegan and vegetarian diets
Published in Front Endocrinol (Lausanne). Study from 2025.
Source: View full study on PubMed
Iodine deficiency and iodine supplementation in pregnancy and lactation. A literature review
Published in Pol Merkur Lekarski. Study from 2025.
Source: View full study on PubMed
Iodine supplementation for pregnancy in Portugal: identification of nutritional composition of iodine containing supplements and characterization of pharmacy dispenses from 2008-2022
Published in Front Endocrinol (Lausanne). Study from 2025.
Source: View full study on PubMed
Do Postpartum Maternal Iodine Status or Supplementation Affect Thyroid Function After Delivery? A Systematic Review and Meta-Analysis
Published in Biol Trace Elem Res. Study from 2024. Comprehensive analysis combining multiple studies.
Source: View full study on PubMed
Effects of iodine supplementation on thyroid function parameter: Systematic review and meta-analysis
Published in J Trace Elem Med Biol. Study from 2023. Comprehensive analysis combining multiple studies.
Source: View full study on PubMed
An update: maternal iodine supplementation, thyroid function tests, and child neurodevelopmental outcomes
Published in Curr Opin Endocrinol Diabetes Obes. Study from 2023.
Source: View full study on PubMed
The research summaries above are based on published peer-reviewed studies and are provided for informational purposes only. Study findings may not apply to all individuals, and the presence of a study summary does not constitute an endorsement of iodine for any specific health condition. Always consult a qualified healthcare professional before making decisions based on research findings.
Important Information
How Storage Affects Supplement Potency and Shelf Life
Proper storage is essential for maintaining supplement potency over time. Heat, moisture, light, and air exposure can all degrade active ingredients, sometimes significantly reducing the amount of nutrient you actually receive per serving. Probiotics are particularly sensitive to temperature and may lose viability if not refrigerated as directed. Fish oil and other omega-3 supplements can oxidize when exposed to light or heat, potentially producing harmful byproducts and an unpleasant fishy taste or odor.
To maximize supplement shelf life, store products in a cool, dry place away from direct sunlight — the bathroom medicine cabinet, despite its name, is often too warm and humid. Always check expiration dates before purchasing and using supplements, as potency declines over time even under ideal storage conditions. If a supplement has changed color, developed an unusual odor, or appears clumped or discolored, it may be degraded and should be discarded.
This Is Not Medical Advice
All content on Zynava, including supplement information pages, research summaries, dosage ranges, and health tool results, is provided for general educational and informational purposes only. Nothing on this website should be interpreted as a diagnosis, treatment recommendation, or substitute for professional medical advice. Supplement research is complex and evolving — study results may not apply to every individual, and what works in a clinical trial may not produce the same results in real-world use.
Always consult a qualified healthcare provider before starting, stopping, or changing any supplement regimen, especially if you are pregnant, nursing, taking prescription medications, or managing a chronic health condition. Your doctor or pharmacist can help you evaluate whether a specific supplement is appropriate for your individual circumstances.
This content is for general educational purposes only and is not intended as medical advice. Consult a healthcare professional before starting any supplement. Individual results may vary. See our full disclaimer and affiliate disclosure.