Is a spoonful of Irish moss the key to good health?

It’s full of nutrients and has plenty of celebrity fans, but how much good can this spiky sea vegetable really do for you?

In videos on TikTok, influencers wince as they dig spoons into jars of what looks like slime. Sometimes the glop is pale green or yellow, sometimes it’s deep red. Some people wrinkle their noses and grimace as they swallow a dollop; others sniff their spoons and grin into the camera. “It kind of smells like ocean water,” one woman says before choking down a glob and then covering her mouth, appearing to gag, eyes watering. “It’s really good,” she says flatly and unconvincingly, blinking away tears. “I’m going to do it every day.”

They are among a number of people online who have been promoting the health benefits of Irish moss, aka carrageen moss or sea moss. Found along the rocky Atlantic coasts of Europe and North America, including the west coast of Ireland, it’s an edible sea vegetable in the algae family that is packed with nutrients like folate, vitamin K, vitamin B, iron, iodine, magnesium, zinc and calcium.

While the plant can be consumed raw and in supplement form — including as pills, powders and gummies —, it’s most often eaten as a gel, made by soaking the dried plant in water, blending it and letting it coalesce in the fridge. Some claim that a scoop or more per day can heal their gut, clear their skin, regulate their menstrual cycle, strengthen their immune system or help them shed pounds. But is this hype based on science?

Here’s what to know before slurping down a spoonful.


What is sea moss?

Sea moss is a spiky, frilly sea vegetable that somewhat resembles frisée lettuce when it’s in the ocean. It thrives along the Atlantic coasts, mainly between North America and Europe, and in the warm waters of Asia, South America, Africa and parts of the Caribbean. When dried and packaged, the plant looks like cooked ramen noodles, with tangled tendrils that clump together. Food manufacturers harvest it for its carrageenan, an ingredient that acts as a thickening agent for foods like ice cream, chocolate milk and creamers.

But because it’s so nutrient-rich, people sometimes eat it in the hope of improving their health — swirling the gel into smoothies, blending it into puddings or eating it straight from a jar.

The gel often tastes fishy and has a slick, slimy texture. Raw sea moss can also have an earthy, ocean-like taste, not unlike an oyster or a clam — which can be off-putting to some, according to Brooke Levine, a dietitian nutritionist at NYU Langone Health.

When did sea moss become so popular?

Sea moss has received a number of celebrity endorsements on social media in recent years. In 2020, Kim Kardashian shared on Twitter that she drank sea-moss smoothies as part of her diet; last summer, Erewhon Market, a grocery chain based in Los Angeles, released “Hailey Bieber’s Strawberry Glaze Skin Smoothie” — complete with sea moss gel. The rapper Meek Mill mused online in 2019 that maybe sea moss made him smarter, and in 2021 the former Disney Channel actor Skai Jackson said she ate sea moss “every single day”.

Sea moss also gained attention in the United States last autumn when a flurry of panicky social-media posts from fans of the plant claimed that the US Food and Drug Administration was going to ban all sea-moss products, possibly because of certain unproven health claims. Although the FDA has issued warning letters to makers of sea moss-containing products in the past (including to a company that claimed its product could prevent or treat Covid-19), the posts about the ban turned out to be based on misinformation. But the passionate reactions of some users showed just how fervent a following the plant had gained.

Is sea moss actually good for you?

Sea moss, in gel or other forms, can be a relatively low-calorie conduit to adding more nutrients to your diet, says Dr Melinda Ring, the executive director of the Osher Center for Integrative Health at Northwestern University Feinberg School of Medicine, in Chicago. The plant is rich in antioxidants, which can break down free radicals that damage our cells, she says. And sea-moss gel contains large amounts of potassium, an essential mineral that supports muscle contraction and blood pressure control.

But while nutrition experts say that the nutrients in sea moss might offer some health benefits, the hype is probably overblown, according to Ring. “Like all of the superfoods that have come and gone, there’s some truth to it,” she said. “It’s just not a magical thing that everyone should be taking.”

No clinical trials have investigated whether sea moss is beneficial for humans, Levine says, though seaweed in general has been well researched: it’s packed with vitamins and minerals similar to those found in sea moss, and some studies suggest that certain fatty acids and vitamins in some types of seaweed, like omega-3 fatty acids and vitamins D and B12, can help strengthen the immune system.

But without hard and fast data on sea moss itself, Ring says, its health effects aren’t totally clear.

Besides, Levine says, you’re most likely already getting the same nutrients found in sea moss if you follow a well-balanced diet. And if you don’t, she says, consuming sea moss won’t counteract poor nutrition choices. “It won’t help to eat sea-moss gel if you’re getting a Big Mac.”

Instead of turning to sea moss for a nutritional boost, she says, a few rolls of sushi containing seaweed can help supply comparable amounts of B vitamins and zinc. You can also get many of the nutrients in sea moss from leafy greens like kale, arugula or Swiss chard, according to Mary Ellen DiPaola, a senior outpatient dietitian at the University of California, San Francisco.

Kristin Kirkpatrick, a dietitian at the Cleveland Clinic, agrees. “When a patient comes to me and says, ‘I saw this on TikTok, I’m thinking about taking it,’ I’m, like, ‘That’s great. How about having more broccoli?’”

Can sea moss help you lose weight?

Despite what some people are saying online, sea moss won’t suddenly speed up your metabolism, according to Kirkpatrick. It does, however, contain plenty of prebiotic fibre, a food source for the good bacteria in your gut, which can help regulate your digestive system, she says.

Theoretically, sea-moss gel could contribute to weight loss because its goopy consistency makes it slow to leave our stomachs, keeping us fuller for longer, according to Ring, but it’s not guaranteed.

Can sea moss keep you from getting sick?

The individual nutrients found in sea moss — like B vitamins and zinc — indicate that, theoretically, the gel could help support your immune system, Ring says. But without data or clinical trials there’s no proof that sea moss can prevent or cure any disease.

Are there risks associated with eating sea moss?

Sea moss contains high levels of iodine, which can damage your thyroid if consumed in large quantities, Ring says. If you want to try it, she recommends taking no more than two tablespoons of the gel at a time and using it every other day, rather than every day.

Like seaweed, sea moss may contain trace amounts of heavy metals like aluminium or cadmium, depending on where it’s grown. So you should be careful to not overdo it, Ring says.

Food supplements are regulated in the European Union; the packaging must be clear about exactly what the supplement contains, and must not make health claims about the supplement.

Is sea moss worth shelling out for?

Several Irish companies sell sea moss, usually in dried or powdered form (such as here and here and here)

Swallowing a spoonful of sea moss isn’t likely to harm you, experts say. But it won’t transform your health or body, either.

“When we’re having a conversation about diet, there’s never been a situation where we’ve found one food is the salvation we were searching for,” Kirkpatrick says. “It’s always a combination of factors.” – This is an edited version of an article that originally appeared in The New York Times