Sea moss benefits: what's in it and what does research say?

Short answer: Sea moss (Irish moss, Chondrus crispus) is a red seaweed that consists mainly of carrageenan, a fibre-like substance that forms a gel with water, plus some protein and minerals, including iodine. Sea moss itself has hardly been studied in humans: the studies that exist are mainly about its composition, about animals and about the lab. The benefits that may officially be claimed in the EU are about iodine; you will find them further down this article.

Last updated: 5 November 2026 · Written by Florian Fermin

At GOYU we sell sea moss gel and sea moss capsules. Online you often find lists of ten or twenty sea moss benefits. Here you can read what is really in it, what research shows and what it does not. The basics, such as where sea moss comes from and how to use it, are in our sea moss guide.

What is sea moss?

Sea moss is the popular name for Irish moss, also called carrageen moss or seamoss. It is a small red seaweed, usually no longer than 20 cm, that grows on rocks along the Atlantic coasts of Europe and North America. In Ireland and the Caribbean it has been eaten for centuries, for example in puddings and drinks. In the European Novel Food Catalogue, Chondrus crispus is listed as not novel in food: it was already eaten in the EU before 1997 (EU Novel Food Catalogue).

Note: not everything sold online as sea moss is Chondrus crispus. Check the label for the Latin name.

What is in sea moss?

According to the description in the EU Novel Food Catalogue, dried Irish moss consists of about 55% carrageenan, almost 10% protein and about 15% minerals. The catalogue also describes the seaweed as rich in iodine and sulphur.

Research shows how much these levels vary. In an Italian analysis of 14 seaweeds bought in shops, mineral levels differed between species by a factor of 100 to 10,000; Chondrus crispus had the highest sulphur content of all seaweeds tested (Desideri et al., 2016). That is why we do not state fixed mineral or iodine levels.

Does sea moss really contain 92 minerals?

You see that number everywhere, but we have not found any research that backs it up. What is true: sea moss naturally contains various minerals, and how much it contains varies per harvest. A figure like 92 of the 102 minerals therefore says little about what you get from a tablespoon of gel or a capsule.

How much iodine is in sea moss?

That varies greatly per species, per harvest and per product. In a Norwegian study of 96 seaweed products, one portion of pure seaweed contained 128 to 62,400 micrograms of iodine, and 54 products already exceeded the safe upper limit with a single portion or dose. Brown seaweeds such as kelp and kombu contained the most (Aakre et al., 2021). Iodine has also been measured in Irish moss, with differences between samples (Darias-Rosales et al., 2020).

These values come from the Netherlands Nutrition Centre (Voedingscentrum), which advises against kelp tablets because the iodine content of kelp varies so much. That is why our sea moss gel and capsules say: do not use if you have a thyroid condition or take thyroid medication. If you already use other products with seaweed or iodine, check with your doctor first.

What does research say about sea moss?

Sea moss itself has hardly been studied in humans. In a PubMed search (November 2026) we found no controlled human studies with Irish moss as a food or supplement. What does exist:

• Composition. Analyses of minerals, iodine and heavy metals in seaweed from shops (Desideri et al., 2016; Aakre et al., 2021).
• Animal studies. In one study, young rats were fed cultivated Irish moss, and researchers looked at the gut flora and the substances gut bacteria produce (Liu et al., 2015). Irish moss has also been tested as feed for dairy cows, including its effect on iodine metabolism (Reyes et al., 2025).
• Lab studies with extracts on cells or on tiny roundworms. They say little about what a tablespoon of gel or a capsule does in humans.

Animal and lab studies are a start, but you cannot simply apply the results to humans. If you read somewhere that sea moss does something for your immunity, gut, skin or energy, ask for the human research. We wrote a separate article about sea moss and the skin: sea moss and the skin.

Which sea moss benefits may officially be claimed?

In the EU, foods and supplements may only use health claims that have been authorised or are still being assessed. No health claim has been authorised for sea moss as a plant. For iodine there are. For our sea moss gel we use these claims:

• Source of iodine**
• Iodine contributes to normal cognitive function**
• Iodine contributes to normal functioning of the nervous system**
• Iodine contributes to the maintenance of normal skin**

**Authorised health claim (Regulation (EU) No 432/2012) or nutrition claim (Regulation (EC) No 1924/2006).

We do not use health claims for our sea moss capsules.

What should you look out for with sea moss?

• Iodine: stick to the daily dose on the packaging and don't casually combine sea moss with other seaweed or iodine products.
• Heavy metals: seaweed absorbs substances from the water it grows in. In the EU, maximum levels apply to food supplements for lead, cadmium and mercury, among others (Regulation (EU) 2023/915). So choose sea moss with a clear origin and a lab test. More on this in why the origin of your seaweed matters.
• Pregnant, breastfeeding, taking medication or have a medical condition: check with your doctor first. That is also on the label.
• Children: our sea moss gel is not intended for children. Keep both products out of reach of young children.

Sea moss gel or capsules: does it matter?

It is the same seaweed, just processed differently. Our sea moss capsules contain 500 mg of dried and ground Irish moss per capsule; you take 1 a day, preferably during or just after a meal. Our gel consists of Irish moss, water, lime juice and potassium sorbate; adults take 1 to 2 tablespoons a day. How much dried seaweed is in a tablespoon of gel differs per brand and recipe, so you cannot convert them exactly. Choose based on convenience and taste. The comparison is in sea moss gel or capsules, and recipes and tips for the gel in how to use sea moss gel.

Summary in 3 points

• Sea moss (Chondrus crispus) is a red seaweed that consists mainly of carrageenan, with some protein and minerals, including iodine.
• Sea moss has hardly been studied in humans; most studies are about its composition, about animals and about the lab.
• The benefits that may officially be claimed are about iodine. So stick to the daily dose and watch out for other sources of iodine.

Frequently asked questions

What is sea moss good for?

Sea moss is first and foremost a food: a seaweed you use in smoothies, desserts and drinks, and thanks to the carrageenan also as a thickener. The benefits that may officially be claimed are about iodine. For our sea moss gel, those claims are listed above.

Is sea moss healthy?

Sea moss mainly contains carrageenan, some protein and minerals, including iodine. How healthy it is for you depends mostly on how much you take and how much iodine you already get from other food. Human research on sea moss itself is still lacking.

How much sea moss should you take per day?

Adults take 1 to 2 tablespoons a day of our gel, or 1 capsule a day of our capsules. Do not exceed the recommended daily dose, and check with your doctor first if you also use other products with seaweed or iodine.

Does sea moss have side effects?

The main point of attention is iodine: too much iodine is not good, especially with a thyroid condition or thyroid medication. The label of our capsules says: preferably take them during or just after a meal.

Is sea moss the same as Irish moss?

Yes. Sea moss, seamoss, Irish moss and carrageen moss are all names for the red seaweed Chondrus crispus. In French it is called mousse d'Irlande, in German Irisch Moos.

Sources

1. European Commission. Novel Food Catalogue, entry Chondrus crispus (POL-NF-00243), status: not novel in food. ec.europa.eu
2. Desideri D et al. (2016). Essential and toxic elements in seaweeds for human consumption. Journal of Toxicology and Environmental Health, Part A. Analysis of 14 seaweeds from shops. doi.org/10.1080/15287394.2015.1113598
3. Aakre I et al. (2021). Commercially available kelp and seaweed products: valuable iodine source or risk of excess intake? Food & Nutrition Research 65. Analysis of 96 products. doi.org/10.29219/fnr.v65.7584
4. Darias-Rosales J et al. (2020). Risk assessment of iodine intake from the consumption of red seaweeds (Palmaria palmata and Chondrus crispus). Environmental Science and Pollution Research. 30 samples. doi.org/10.1007/s11356-020-10478-9
5. Liu J et al. (2015). Prebiotic effects of diet supplemented with the cultivated red seaweed Chondrus crispus or with fructo-oligo-saccharide on host immunity, colonic microbiota and gut microbial metabolites. BMC Complementary and Alternative Medicine 15:279. Study in rats. doi.org/10.1186/s12906-015-0802-5
6. Reyes DC et al. (2025). Feeding incremental amounts of the red seaweed Chondrus crispus: effects on production performance, methane emissions, nutrient utilization, and ruminal and iodine metabolism in dairy cows. Journal of Dairy Science. Study in dairy cows. doi.org/10.3168/jds.2024-26244
7. Voedingscentrum (Netherlands Nutrition Centre). Jodium (iodine). voedingscentrum.nl
8. Commission Regulation (EU) 2023/915 on maximum levels for certain contaminants in food. eur-lex.europa.eu
9. Product information and labels of GOYU Sea Moss Gel and Sea Moss Capsules 500 mg Organic, accessed 5 November 2026.

This article is for information only and is not medical advice. Seaweed naturally contains iodine. If you have a thyroid condition, take thyroid medication, are pregnant or breastfeeding, check with your GP or pharmacist first. Food supplements are not a substitute for a varied diet and a healthy lifestyle.