Two bowls on a wooden table: dried, pale seaweed in a wooden bowl and soaked, translucent seaweed in water in a ceramic bowl.

Sea Moss Capsules vs Gel: What the Label Can Prove

Michael Hofer

Sea moss capsules vs gel comes down to what each label can prove about a serving. A capsule label usually gives a weight of dried sea moss per serving, and sometimes other herbs. A gel is mostly water, and its label may give only the weight of the gel. To compare them fairly, write down the species, the sea moss weight per serving, every added ingredient, whether iodine is listed and what the brand says about testing.

Key takeaways

  • Write down the species on each label. The NIH LactMed database describes sea moss as Irish moss (Chondrus crispus), and some products add bladderwrack or other herbs. Write down each one with its amount.
  • A gel's weight is not its sea moss weight. USDA FoodData Central lists 81.3 grams of water in 100 grams of raw Irish moss, and gels are usually blended with more water.
  • Seaweed iodine varies widely, and a sea moss label may give no iodine amount. Record whether iodine is listed and what the brand says it tests for, such as heavy metals.

What "sea moss" means on a label

The Drugs and Lactation Database (LactMed), run by the National Institute of Child Health and Human Development, describes sea moss or Irish moss (Chondrus crispus) as a red seaweed used as food. It says sea moss contains carrageenan and other carbohydrates, and numerous minerals, including iodine.

Some sea moss supplements also contain bladderwrack. The same database describes kelp, also known as bladderwrack (Fucus vesiculosus, other Fucus species and Ascophyllum nodosum), as the dried whole plant, and says it contains soluble fiber, vitamin B12, iron and iodine. Write down the Latin name of each seaweed when the label gives one.

Capsules, gel and dried moss: what changes

  • Capsules. The serving is a set number of capsules. Check the serving size, the weight of each seaweed or herb per serving and the number of servings per day.
  • Gel. The serving is often a spoonful or a weight of gel. Check whether the label says how much sea moss is in that serving, or only how much gel. Follow the storage directions on the jar.
  • Dried whole moss. This is a food you prepare yourself. The amount you eat depends on how much you soak and how much water you add.

Why gel weight is not sea moss weight

Raw sea moss is already mostly water: USDA FoodData Central lists 81.3 grams of water in 100 grams of raw Irish moss. Gels are made by soaking the moss and blending it, usually with more water, so the share of sea moss in a spoonful depends on the recipe.

Soaking and cooking can also change what is in the seaweed. A 2021 study in Food and Chemical Toxicology rehydrated and boiled four seaweeds, including Irish moss, and found that part of their iodine, arsenic and selenium came out into the water, by different amounts for each species. The authors say that in some species, high iodine and arsenic levels might still pose risks after 20 minutes of boiling. So a test of dried moss may not describe a soaked or cooked product.

How to compare the label lines

Record the same lines for each product, then compare dried weight with dried weight, and gel with gel.

Label line What to write down
Species Each seaweed named, with its Latin name if given
Format and serving Capsules per serving, or the gel serving in spoons or grams, and servings per day
Sea moss amount Milligrams of sea moss per serving, or "gel weight only"
Other ingredients Each added seaweed or herb and its amount, or "sea moss only"
Iodine The iodine amount per serving, or "not listed"
Testing statement The brand's exact words about outside testing
Certificate of analysis Offered, on request, or not mentioned

Sea moss alone or with other herbs

A sea moss-only product and one that adds bladderwrack, burdock root or black pepper extract are simply different formulas. Put each ingredient on its own line with its amount, and line up sea moss against sea moss. Copy any extract ratio, such as 10:1, exactly as printed, and compare it only with another ratio. When a label groups ingredients in a blend with one total weight, record that total; the amounts inside the blend are not stated.

Iodine: what a label can and cannot show

The NIH Office of Dietary Supplements (ODS) says seaweed is one of the best food sources of iodine and that iodine amounts in different seaweed species vary greatly. A 2004 study in the journal Thyroid tested 12 species of seaweed and found iodine from 16 mcg per gram in nori to more than 8,165 mcg per gram in one sample of processed kelp granules. The same study says iodine dissolves in water during cooking and may vaporize in humid storage, which makes the iodine in prepared foods difficult to estimate.

Because of this, the weight of sea moss on a label does not tell you its iodine amount. If a label lists iodine per serving, write the amount down. If it does not, the iodine amount is not stated; that does not mean the serving has none.

The Food and Nutrition Board's tolerable upper intake level for iodine, listed by ODS, is 1,100 mcg a day for adults 19 and older, from food and supplements. ODS says many multivitamin/mineral supplements contain iodine, often at a dose of 150 mcg. If you take more than one product with iodine, add up the amounts that are listed, and note any product that gives no iodine amount.

Testing and heavy metals

LactMed says sea moss can contain some toxic heavy metals, such as arsenic, lead, cadmium and mercury, that come from the water where it was grown. It says bladderwrack can also contain heavy metals such as arsenic, cadmium and lead.

The label lists what a product should contain, not what a lab found in a given batch. NCCIH says a manufacturer's use of "standardized," "verified" or "certified" does not necessarily mean the product is of consistent quality. ODS names ConsumerLab.com, NSF International and U.S. Pharmacopeia as organizations whose seal shows a product passed their quality testing, and says a seal is not proof that a product is safe or effective. For each product, note what the brand says it tests for, such as heavy metals, and whether a certificate of analysis (a batch test report) is posted or offered on request. A report that is not public does not show that a product was untested.

Safety: what to know before you start

ODS says some people, such as those with autoimmune thyroid disease and iodine deficiency, may have adverse effects with iodine intakes considered safe for the general population. It also says that taking high doses of iodine with antithyroid medications, such as methimazole, can have an additive effect and could cause hypothyroidism, and that people who take these medications regularly should discuss their iodine intakes with their health care providers.

LactMed says excess iodine from seaweed eaten by a nursing mother has caused thyroid suppression in breastfed infants, and that sea moss should be avoided during breastfeeding unless the levels of iodine and heavy metals have been shown to be low enough to be safe. NCCIH says dietary supplements may interact with your medications or pose risks if you have certain medical problems or are going to have surgery. Bring the label to your health care provider if you take other supplements or medicines.

Frequently asked questions about sea moss capsules vs gel

Are sea moss capsules different from sea moss gel?

Yes, mainly in how the serving is measured. A capsule label usually gives a weight of dried sea moss per serving, while a gel is mostly water and its label may give only the gel weight.

How do I compare a gel serving with a capsule serving?

Use the sea moss amount each label states, not the total weight of the gel. USDA FoodData Central lists 81.3 grams of water in 100 grams of raw Irish moss, and gels are usually blended with more water. If a gel label gives only the gel weight, the sea moss amount per serving is not stated.

Do sea moss labels list iodine?

Some do and some do not. The NIH Office of Dietary Supplements says iodine amounts in seaweed species vary greatly, so the sea moss weight does not tell you the iodine amount. If a label gives no iodine amount, the amount is not stated; that does not mean the product has none.

Can sea moss contain heavy metals?

Yes. The NIH LactMed database says sea moss can contain toxic heavy metals, such as arsenic, lead, cadmium and mercury, from the water where it was grown. Record what each brand says it tests for and whether it offers a certificate of analysis for the batch.

What is bladderwrack on a sea moss label?

Bladderwrack (Fucus vesiculosus, other Fucus species and Ascophyllum nodosum) is a seaweed that some sea moss products add. The NIH LactMed database says it contains iodine and can also contain heavy metals such as arsenic, cadmium and lead. Check that the label lists it with its own amount per serving.

Related reading

Sources

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If you are pregnant, nursing or trying to conceive, ask your healthcare provider before use.

This article is for education and is not personal medical advice. Individual results vary.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

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