Best Iodine Supplements 2026: Cost per Effective Dose
Top pick for Iodine: Nutricost Kelp Tablets, 325mcg Iodine — 325mcg per 1 tablet, None stated, $0.05/day. Our best-value pick.
All Iodine Supplements Compared
All 4 products sorted by cost per labelled serving (lowest first). Dose, certification, and pricing verified against NIH DSLD and manufacturer data.
Read the dose column before the price column. Servings in this category are not equivalent — they range from 150 to 1,000 mcg per serving. A lower cost per day here can simply mean a smaller serving, so the cheapest row is not automatically the best value.
| Product | Brand | Dose / Serving | Cost / Day | Certification | Pick | Buy |
|---|---|---|---|---|---|---|
| NOW Supplements Kelp, 150mcg Natural Iodine | NOW Foods | 150mcg / 1 tablet | $0.04 | None stated | Buy | |
| NOW Supplements Kelp, 325mcg Natural Iodine | NOW Foods | 325mcg / 1 veg capsule | $0.05 | None stated | Buy | |
| Nutricost Kelp Tablets, 325mcg Iodine | Nutricost | 325mcg / 1 tablet | $0.05 | None stated | Best Value | Buy |
| Life Extension Sea-Iodine, 1000mcg | Life Extension | 1000mcg / 1 veg capsule | $0.11 | None stated | Buy |
In-Depth Iodine Guides
Go deeper on iodine — by goal, by form, and what the evidence actually supports:
Our Picks
Best Value: Nutricost Kelp Tablets, 325mcg Iodine
325mcg per 1 tablet. None stated. $0.05/day. 240 servings per container at $11.95.
How We Rank Iodine Supplements
Every product is evaluated on three criteria:
- Cost per day. Not cost per pill or cost per bottle — what it actually costs per day at the product's labelled serving. Where a category's servings differ in strength we flag it above the table, because cost per day is only comparable when the doses are.
- Third-party certification. USP Verified, NSF Certified for Sport, and ConsumerLab Approved indicate independent testing for purity, potency, and contaminants.
- Bioavailable form. We prioritize products using the specific chemical form shown to be most effective in published research.
Rankings are not influenced by affiliate commissions. We earn the same commission regardless of which product you choose. Read our full methodology.
Personalize Your Iodine Choice
Not sure which iodine supplement is right for you? Use our free tools:
- DNA Supplement Analyzer — upload 23andMe or AncestryDNA data to check for genetic variants affecting iodine metabolism. Runs entirely in your browser.
- Lab Results Interpreter — enter your blood test values to get personalized dosing recommendations.
- Supplement Stack Builder — build a complete protocol based on your age, sex, medications, and goals.
- Supplement Audit — already taking iodine? Check if you have the right form and dose.