EVERY ONCE IN a while, another wild health trend or supplement hits mainstream popularity that makes you wonder, “can this really benefit my health?”

Buckle up, folks—we’ve got another for you. Right now, Irish Sea moss is circulating on social media as the next best thing for your health. Advertisements are boasting that this plant can help support healthy joints, skin, and hair, as well as boost immune health. Really? Moss? From Ireland?

Let's look at the facts. “Irish Sea moss is a type of seaweed or algae that contains vitamins, minerals, and antioxidants,” says Johna Burdeos, R.D., a registered dietitian. “In particular, it supplies iodine, iron, magnesium, phosphorus, zinc, and copper.”

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It sounds good, but can something this wild sounding have legit health benefits, or is it another way to separate you from your money? We’re bringing the answers to the surface.

What is Irish Sea Moss?

Sea moss comes in two forms: Irish Sea moss or red seaweed. It’s found in the Atlantic Ocean, along the coasts of the United States, Canada, and well, Ireland. It is often harvested in New England.

“Sea moss comes in different colors such as green, yellow, red, and purple. Irish Sea moss is a species of the red algae family,” says Burdeos. It is also known as carrageenan and Chondrus crispus. It is added to products like puddings, ice cream, and even toothpaste. Irish Sea moss also has properties that make it useful in preservatives, she says.

What Are the Benefits of Irish Sea Moss?

Science has a ways to go to catch up with the health halo hype that you see associated with Irish Sea moss.

“There are not many studies showing the effects of sea moss on human health,” says Burdeos. Most of the existing studies on humans are small and other studies have been done on animals and in vitro, meaning in a test tube or culture disk—nowhere near the level of testing needed to see results in humans.

There are more studies on seaweed in general than there are specifically on Irish Sea moss. Seaweed is a close cousin to Irish Sea moss, and has been shown to support gut health because of its fiber content. It’s also been shown to have some effect on reducing the risk of heart disease and thyroid issues, because of its iodine content.

The bottom line is there’s no scientific research to support that Irish Sea moss supplements would have a for-sure effect on your health, but it does contain some vitamins and minerals your body needs.

Are There Any Risks With Taking Irish Sea Moss?

Let’s consider the risks of consuming seaweed in general versus Irish Sea moss, since it’s more researched and their makeup is essentially the same.

While there are potential risks to having too much seaweed, they're not very likely. Seaweed is a great source of iodine, a mineral our bodies need to survive. Far too much of it can be harmful to thyroid health, but take a look at what that really means: About 150 mcg daily is recommended by the NIH, and one serving of seaweed has about 116 mcg. You would need to consume over 18,000 mcg a day for multiple days to be at risk of iodine toxicity. You should watch out for high levels of heavy metals in your seaweed, though.

“Seaweed can absorb heavy metals from the waters where it grows. And heavy metals consumed in large amounts can result in neurological, kidney, liver, and heart damage as well as cancer,” says Burdeos. “It’s important to note that the nutrient content in sea moss (and seaweed in general) can vary due to the seasonality and ecology of the harvesting location."

There's no legislation requiring seaweed companies to test for heavy metals, so double check to make sure the brand you're buying does. You can typically find this information on the packaging or on its website.

Should I Be Taking an Irish Sea Moss Supplement?

You really don’t need to. There’s no such thing as being ‘deficient’ in Irish Sea moss, but you may be deficient in some of the nutrients it provides, like iodine and magnesium. If you aren't meeting the requirements in those things, it’s best to talk to a doctor to see what the best course of action is. They may just advise you to go on a regular magnesium or iodine supplement rather than Irish Sea moss. As always, consult with your doctor before trying anything, especially if you have medical conditions.

“If you are already eating a varied diet that includes fruits, vegetables, whole grains, lean proteins, and healthy fats, there is no reason to incorporate a supplement, including Irish Sea moss, unless your doctor advises,” she continues.

If you’re really bugging to try it, just make sure you do so safely. According to a 2020 study, an appropriate serving for adults is about four grams daily, says Burdeos. She recommends selecting from reputable brands that are transparent about the ingredients in their supplement products. You can get it in gel, capsule, or powder form depending on your personal preference.

Look at the dosages and check for a third-party lab test when selecting a product, Burdeos says. Since supplements are not regulated by the FDA, a third-party lab test “shows transparency in product ingredients and that what you read on the label is what you get. It also ensures the product is free from impurities or contaminants, such as heavy metals.”

Headshot of Perri O. Blumberg
Perri O. Blumberg

Perri is a New York City-born and -based writer; she holds a bachelor’s in psychology from Columbia University and is also a culinary school graduate of the plant-based Natural Gourmet Institute, which is now the Natural Gourmet Center at the Institute of Culinary Education. Her work has appeared in the New York Post, Men's Journal, Rolling Stone, Oprah Daily, Insider.com, Architectural Digest, Southern Living, and more. She's probably seen Dave Matthews Band in your hometown, and she'll never turn down a bloody mary. Learn more at VeganWhenSober.com.