Sea Moss and Bladderwrack: Why They Are Paired Together

By Suhail Rivera, JD, founder of Alkaline Herb Shop

Look at almost any sea moss capsule on the market and a second seaweed keeps showing up next to it: bladderwrack. The pairing is so common that many people assume they are the same plant. They are not, and the reason they travel together is a better story than most sellers bother to tell.

Two Different Seaweeds

Sea moss is Chondrus crispus, a red seaweed, the small curly one we cover in full in our guide to what Chondrus crispus is. Bladderwrack is Fucus vesiculosus, a brown seaweed, named for the small air filled bladders along its fronds that keep it upright in the water. Both grow in cold North Atlantic waters, often on the same shores, and both have been gathered by coastal communities for generations.

Where the Pairing Comes From

Combining the two is a tradition, not a modern marketing invention. In Caribbean and Irish coastal tradition, the red and the brown seaweed were gathered and used together for generations, and today's capsules simply continue that pairing in a more convenient form. That is the honest origin: two sea vegetables from the same waters that people have long taken side by side.

What Is Actually in Them

Both are whole sea vegetables, and their minerals are the seaweed's own, not added in a factory. Because the mineral content of any seaweed depends on its harvest, we test ours instead of guessing: an independent lab measured a three capsule serving of our sea moss and bladderwrack capsules and found 561 micrograms of naturally occurring iodine, which is 374 percent of the daily value, and 2 milligrams of iron, which is 11 percent. The full numbers are public on our lab results page.

Does Sea Moss Have Iron?

Yes, and in this pairing the iron is mostly the sea moss's contribution. Our pure sea moss capsules list 4 milligrams of iron per serving on their Supplement Facts panel, which is 24 percent of the daily value, while a serving of the sea moss and bladderwrack blend tests at 2 milligrams, or 11 percent. Read side by side, our own labels tell the story of the division of labor: the sea moss brings the larger share of the iron, and bladderwrack brings the iodine.

The Part That Deserves Respect: Iodine

Bladderwrack typically runs higher in iodine than sea moss, which means the pair together is a high iodine combination. That is a fact to take seriously, not a selling point. 561 micrograms per serving sits within the NIH adult upper intake level of 1,100 micrograms a day, but it is not a product to double up on, and it is not for people with hyperthyroidism. If you have any thyroid condition, talk to your doctor before taking either seaweed. The full picture is in our articles on sea moss and the thyroid and sea moss side effects.

Do You Have to Take Them Together?

No. Sea moss on its own is milder in iodine and comes in more kitchen friendly forms, from raw sea moss for gel making to powder and capsules. The pairing exists for people who want both seaweeds in one measured serving. If you are weighing bladderwrack itself, our guide to what bladderwrack is good for gives it the same honest treatment.

Suhail Rivera, JD, is the founder of Alkaline Herb Shop. She has spent years sourcing, handling, and selling the herbs she writes about, working directly with growers and third party testing labs. She holds a Juris Doctor. She is not a medical professional. This article is for general information only and is not medical advice. Talk to your doctor or pharmacist before starting any herb, especially if you are pregnant, nursing, taking medication or managing a health condition. Read more about her and the store on the About page.