Best Iodine Supplements for Thyroid Support in 2026

Iodine is an essential mineral that your thyroid gland requires to produce thyroid hormones, which regulate metabolism, energy production, and numerous other bodily functions. Despite the widespread use of iodized salt, research suggests that iodine deficiency remains more common than many people realize. Certain populations, including those who limit salt intake, follow plant-based diets, or avoid dairy and seafood, may be at a higher risk of inadequate iodine intake.

Whether you are looking to ensure you meet your daily iodine needs or want targeted thyroid support, a quality iodine supplement can fill the gap. We evaluated dozens of products to identify the five best iodine supplements of 2026.

How We Chose Our Top Picks

We assessed each supplement based on iodine form (potassium iodide, nascent iodine, or kelp-derived), dosage accuracy, third-party testing, label transparency, customer feedback, and value per serving. We prioritized products that provide iodine within the recommended daily intake range and clearly disclose their sourcing.

Our Top 5 Iodine Supplements

1. Life Extension Sea-Iodine

Best Overall

Life Extension's Sea-Iodine provides 1,000 mcg of iodine derived from organic kelp and bladderwrack. This whole-food-sourced approach delivers iodine in a form similar to what you would get from a diet rich in sea vegetables. Each vegetarian capsule is free from common allergens and undergoes third-party testing.

• Iodine per Serving: 1,000 mcg
• Source: Organic kelp and bladderwrack
• Third-Party Tested: Yes
• Notable Feature: Whole-food-sourced from organic sea vegetables

Worth noting: As with any supplement, individual results may vary. Consider starting with a lower dose and gradually increasing as needed. Always check with your healthcare provider before adding a new supplement to your routine.

2. Pure Encapsulations Iodine (potassium iodide)

Best Practitioner Grade

Pure Encapsulations offers a clean, hypoallergenic potassium iodide formula providing 225 mcg of iodine per capsule. This amount provides 150 percent of the daily value, making it a moderate and well-tolerated dose. The brand is trusted by healthcare practitioners and free from all major allergens.

• Iodine per Serving: 225 mcg
• Source: Potassium iodide
• Third-Party Tested: Yes
• Notable Feature: Hypoallergenic, moderate dose, practitioner trusted

Worth noting: As with any supplement, individual results may vary. Consider starting with a lower dose and gradually increasing as needed. Always check with your healthcare provider before adding a new supplement to your routine.

3. Thorne Iodine and Tyrosine

Best Thyroid-Focused Formula

Thorne combines iodine with L-tyrosine, the amino acid your thyroid uses alongside iodine to synthesize thyroid hormones. Each capsule provides 225 mcg of iodine and 500 mg of L-tyrosine, making it a targeted formula for thyroid support rather than iodine alone.

• Iodine per Serving: 225 mcg
• Source: Potassium iodide plus L-tyrosine
• Third-Party Tested: NSF Certified for Sport
• Notable Feature: Combines both raw materials for thyroid hormone production

Worth noting: As with any supplement, individual results may vary. Consider starting with a lower dose and gradually increasing as needed. Always check with your healthcare provider before adding a new supplement to your routine.

4. NOW Foods Kelp Capsules

Best Natural Source

NOW Foods sources their iodine from North Atlantic kelp, providing 150 mcg per capsule — exactly 100 percent of the daily value. For those who prefer getting iodine from a natural whole-food source at a gentle, maintenance-level dose, NOW Kelp is a reliable and affordable option.

• Iodine per Serving: 150 mcg
• Source: North Atlantic kelp
• Third-Party Tested: GMP Certified
• Notable Feature: Whole-food source at 100 percent daily value

Worth noting: As with any supplement, individual results may vary. Consider starting with a lower dose and gradually increasing as needed. Always check with your healthcare provider before adding a new supplement to your routine.

5. Nutricost Potassium Iodide

Best Value

Nutricost delivers a straightforward potassium iodide supplement at an extremely competitive price. Each capsule provides 225 mcg of iodine, and with 240 capsules per bottle, a single purchase provides an eight-month supply. For those who want consistent iodine supplementation without a premium price tag, Nutricost delivers.

• Iodine per Serving: 225 mcg
• Source: Potassium iodide
• Third-Party Tested: Yes
• Notable Feature: Outstanding value with large bottle size

Worth noting: As with any supplement, individual results may vary. Consider starting with a lower dose and gradually increasing as needed. Always check with your healthcare provider before adding a new supplement to your routine.

Buying Guide: What to Look For

Iodine Form

Potassium iodide is the most common and well-studied supplemental form. Kelp-derived iodine provides iodine in a whole-food matrix but iodine content can vary between batches. Nascent iodine is marketed as a more bioavailable form, though clinical evidence supporting this claim is limited.

Dosage Considerations

The recommended daily intake for iodine is 150 mcg for most adults, 220 mcg during pregnancy, and 290 mcg during breastfeeding. The tolerable upper intake level is 1,100 mcg per day for adults. Both deficiency and excess can affect thyroid function, so more is not necessarily better with iodine.

Who May Need Iodine Supplements

People who follow plant-based diets, avoid iodized salt, limit dairy consumption, or live in iodine-deficient geographic regions may benefit from supplementation. If you suspect a thyroid issue, get tested before supplementing, as excessive iodine can worsen certain thyroid conditions.

Final Thoughts

Iodine is a critical mineral for thyroid health and overall metabolic function. The right supplement can help ensure you meet your daily needs, particularly if your diet may not provide sufficient iodine. Choose a product that matches your dose requirements, comes from a reputable manufacturer, and undergoes third-party testing. And remember, with iodine, the goal is adequacy, not excess. Work with your healthcare provider to determine the right amount for your individual needs.

Related Articles

• Best Kelp Supplements for Thyroid and Mineral Support in 2026
• Best Manganese Supplements for Bone and Metabolic Health in 2026
• Best Thyroid Support Supplements in 2026

Key Research

• A large 2022 meta-analysis found that vitamin D supplementation was associated with reduced risk of autoimmune disease (BMJ, 2022).
• The Endocrine Society recommends adults at risk of deficiency maintain serum levels of at least 30 ng/mL (Journal of Clinical Endocrinology & Metabolism, 2011).
• A 2019 meta-analysis found vitamin D supplementation reduced the risk of acute respiratory infections (BMJ, 2019).