A Brief Look at Iodine's Place in Traditional Medicine Systems

Different traditional medicine systems have referenced iodine-containing substances for centuries. A historical, non-clinical overview of how these traditions discussed iodine-rich materials.

Before Anyone Knew Iodine Existed

Iodine wasn't identified as an element until 1811. But for thousands of years before that, people in many parts of the world used iodine-rich materials, especially seaweed and sea sponges, in food and in traditional remedies. They had no way of knowing what made these materials distinctive. Looking back, historians recognize that iodine was very likely part of the reason they were valued.

East Asia

Seaweed has been part of coastal diets in China, Japan and Korea for millennia. Classical Chinese materia medica texts list several seaweeds, including kelp (kunbu) and sargassum (haizao), among their recorded substances. In Japan and Korea, seaweeds like kombu, wakame and nori have been everyday foods for centuries, and seaweed soup holds a special place in Korean tradition, often served to new mothers. These food traditions are one reason iodine intake in these countries is among the highest in the world today. See Global Iodine Intake.

The Mediterranean and Europe

Greek and Roman writers described the use of burnt sea sponge and seaweed in their medical writings. In medieval Europe, the medical school at Salerno in southern Italy recorded preparations of burnt sponge and seaweed in the 12th century, and similar preparations appeared in European pharmacies for centuries afterward. Burnt sponge, it turns out, is relatively rich in iodine.

Coastal and Island Communities

Across coastal Ireland, Scotland, Iceland and Wales, seaweeds such as dulse and laver were traditional foods. In the Pacific, seaweeds have long been eaten in Hawaii and across Polynesia. In each case, people living near the ocean had regular access to iodine-rich foods, often without any separate remedy at all.

From Tradition to Science

The link between those traditional materials and iodine became clear only in the 19th century. After Bernard Courtois isolated iodine from seaweed ash in 1811, physicians such as Jean-François Coindet in Geneva began working with purified iodine in the 1820s, explicitly drawing on the older tradition of burnt sponge. That line of work led to Jean Lugol's 1829 solution. See A Timeline of Iodine and The Story of Bernard Courtois.

Reading Traditional Uses Today

Historical use explains where an idea came from; it isn't evidence that a substance does what tradition claimed. Modern nutrition science gives a clearer picture of what iodine does in the body: it's a building block for thyroid hormones, which support normal metabolism. Traditional seaweed-rich diets remain a great example of getting iodine from food. For recipes built around those same foods, try miso soup with wakame or kombu dashi.

Frequently Asked Questions

Is seaweed a reliable source of iodine?
Seaweed is often rich in iodine, but the amount varies enormously by species and preparation. Some kelps contain very large amounts per serving, so variety and moderation are sensible.

Is this historical formula still relevant, or just a marketing story?
It's both. The historical formula has held up because the underlying chemistry works, not just because it's old — but longevity alone isn't a health claim, and any supplement decision should be made with your own health context in mind.

How does iodine relate to thyroid and cellular health specifically?
See our complete guide to iodine's role in thyroid function and cellular health.

Shop Lugol's Solution — the traditional, trusted way people have supported their iodine intake for over 200 years.

Lauren Mitchell covers comparisons, formats, and quality questions for the Iodine Journal.

This article is for general educational purposes only and has not been evaluated by the FDA. It is not intended to diagnose, treat, cure, or prevent any disease, and is not a substitute for advice from a qualified healthcare provider — especially if you are pregnant, nursing, taking thyroid medication, or managing a thyroid condition.