9 Potential Sea Moss Benefits, According to Experts

Sea moss (aka Irish moss) is a form of algae that has many purported benefits. In my research, I’ve heard that it might help stimulate proper thyroid function, boost the immune system, reduce inflammation and improve digestion. These claims have helped sea moss gain its current superfood status. Oh, and it doesn’t hurt that Kim Kardashian once posted on Twitter that she often adds it to smoothies. But is it really worthy of its superfood status or is it just a fad? Below, I spoke with a nutritionist, health coach and dermatologist to figure out what’s fact and what’s fluff.

• Dr. Ryan Turner is the founder of TRNR Skin and a board-certified, New York City-based dermatologist specializing in cosmetic dermatology, general dermatology, surgical dermatology and laser surgery. He is an Assistant Professor at the Albert Einstein College of Medicine and the former Director of Dermatologic and Laser Surgery at Montefiore Medical Center. Dr. Turner received his medical degree from Harvard Medical School.
• Lisa Young, Ph.D., RDN, is an adjunct professor of nutrition at New York University and internationally renowned nutrition expert. Dr. Young is the author of Finally Full, Finally Slim  and The Portion Teller Plan. She has appeared in outlets such as The New York Times, CNN, Vogue, Wall Street Journal and CBS News.
• Jamie Koll is a certified health coach, ingredient expert and the creator behind the Instagram account @girlswhoeat. The platform offers accessible nutrition and health resources across the food, beauty, supplement, beverage and household industries. She has partnered with brands like Thrive Market, Branch Basics, Primally Pure, cocokind and Spindrift.

“There are thousands of different varieties of seaweed with three main categories: green, red and brown,” Koll tells me. Sea moss is a type of red seaweed, which falls more broadly into the algae family. It also goes by Irish moss and, officially, Chondrus crispus. While there are many studies looking into the benefits of seaweed, there is not that much regarding Irish sea moss in particular. And crucially, not all seaweed is created equal. “Seaweeds have different nutrients and vitamins, so it’s important to know this before buying a certain type if you’re trying to target specific health benefits,” Koll says.

Like any over-the-counter supplement, sea moss isn’t regulated by the FDA in any of its forms (powder, gel or raw), and more studies need to be conducted in order to fully prove or refute its alleged powers. “We just don’t really know if it’s going to do everything some people claim it will,” Young says. “There’s not enough research out there yet.” In fact, much of the research on sea moss has been conducted on animals, not humans. What we do know is that sea moss does contain many nutrients that can benefit your health, including vitamins K and A, fiber, iodine and protein. So where does that leave us? The experts I spoke with agreed that adding sea moss to your diet isn’t harmful, but it may not live up to the hype touted on social media. With that in mind, let’s dive in.

Heart Health

“Sea moss contains 92 out of the 102 minerals that our bodies need, including magnesium, iodine, selenium and potassium,” Koll says. Additionally, it’s high in fiber, known to help reduce levels of “bad” cholesterol (low-density lipoproteins), lower blood pressure and control inflammation, reports the Mayo Clinic. Too much bad cholesterol and a high blood pressure can lead to heart attacks, strokes and heart disease, so keeping them in a healthy range is beneficial for heart health.

Gut Health

One study published in BMC Complementary Medicine and Therapies found that sea moss had a prebiotic effect on rats when consumed. Specifically, it increased the number of fatty acids and good bacteria in the colon, while eliminating bad gut bacteria. “The results suggest multiple prebiotic effects, such as influencing the composition of gut microbial communities, improvement of gut health and immune modulation in rats,” the study concluded. And while there are no human studies confirming the same benefits, it certainly can’t hurt your gut health to add some sea moss to your morning smoothie.

Weight Loss and Cosmetic Benefits

We also know that sea moss contains citrulline–arginine, an amino acid that stimulates metabolism, which can help if you’re trying to lose weight. This compound also synthesizes collagen, which could lead to healthier skin. As explained in Nutrition and Functional Foods for Healthy Aging (Academic Press, 2017), the compound encourages cell growth as it provides a source of nitrogen necessary for protein and collagen formation. The research has indicated the optimal intake of citrulline-arginine could range between 100 and 1,000 milligrams per day.

Thyroid Health

“Sea Moss is high in iodine, which is essential for proper thyroid function,” Koll notes. According to the National Institutes of Health, iodine is necessary for the thyroid hormones, thyroxine and triiodothyronine, which regulate functions such as metabolism and protein synthesis.

Immune System

A 2018 study examined the benefits of seaweed in the diet of Atlantic salmon and found that “The dietary seaweeds provoked a more efficient immune response...Particularly, expression of many important immune receptors was up-regulated illustrating increased responsiveness.” That means, according to researchers, the that fish’s bodies were more quickly able to pinpoint infections and attack the foreign matter, known as antigens. While promising, fish and humans have totally different bodies, and further studies, including those on humans, would be needed to determine if the benefits are the same.

Muscle and Recovery

Irish moss is also a good protein source, and protein is known to aid muscle recovery, growth and repair. Additionally, red seaweed has a high concentration of taurine, an amino acid found in protein structures. A 2021 paper notes that it is a popular supplement for athletes trying to boost performance. “Taurine dosing appears to be effective...which may improve aerobic performance, anaerobic performance (strength, power) [and] recovery,” the authors write. Though, they do note that overall, available data studied yielded inconsistent results, and that further study is necessary to determine how effective taurine is in aiding recovery and mitigating muscle damage.

Parkinson’s

Another study published by the journal Marine Drugs found that sea moss’s anti-inflammatory powers may help protect the brain from diseases like Parkinson’s. In the trial, researchers found that sea moss extract protected worms from toxin-induced neurodegeneration. “These effects were associated with a corrected slowness of movement...Apart from its potential as a functional food, the tested red seaweed, C. crispus, might find promising pharmaceutical applications for the development of potential novel anti-neurodegenerative drugs for humans,” the authors conclude.

In addition to the purported health benefits, sea moss can also supposedly treat acne, seborrheic dermatitis and rosacea, which is why many beauty brands are adding the ingredient to serums, moisturizers and masks.

“Sea moss is naturally rich in carrageenans, a polysaccharide (starch) that can help thicken beauty products but also feature antioxidant benefits as well as anti-inflammatory properties,” Dr. Turner explains. “There are also phenolic compounds, terpenoids, and glycoproteins found in algae that are recognized for their anti-inflammatory benefits. Addressing inflammation is an important part of managing acne, seborrheic dermatitis, and rosacea as these are all inflammatory conditions.”

A 2020 study showed that sea moss had a high concentration of sulfur compared to other types of algae. Sulfur is antimicrobial, though Dr. Turner cautions that there isn’t any hard, specific data on sea moss specifically, so it’s mostly a hypothesis that the algae could help with conditions caused by bacteria (like acne). “Furthermore, [the table only shows] the sulfur content when the algae is reduced to a biomass, and the sulfur may not be in a chemical form that is freely ‘available’ to treat skin conditions,” he adds. “More research needs to be done, and we can only hypothesize that these compounds may be helpful.”

The FDA’s FoodCentral database shows that sea moss contains vitamin A and K, though in very small amounts. As we know, vitamin A often appears as retinol, which is used to exfoliate and clean pores, boost collagen and help minimize the appearance of lines and wrinkles. Meanwhile, vitamin K is often found in eye creams. “[It’s used] to help with dark circles, given that purported mechanisms that it may help with the blood vessel fragility under the eye or that its antioxidant properties help with discoloration,” Dr. Turner explains. “Vitamin K itself may help calm the skin and reduce redness, so [it] might be useful for rosacea, but there is no clear data.”

Before you load up your plate, there are some caveats to consider when incorporating sea moss into your diet.

Too Much Iodine

“If you’re taking medication for your thyroid, you have to be careful of your iodine intake,” Young explains. “Sea moss is rich in iodine, which is good for your thyroid, but if you’re already taking medication that has iodine in it, you could have way too much of a good thing here and it could negatively affect the gland.” Excess iodine intake can lead to hyperthyroidism, hypothyroidism, an enlarged thyroid gland and thyroid autoimmunity.

Heavy Metals

“Depending on where the sea moss is harvested, it can contain heavy metals,” Koll says. “You want to purchase from a reputable company that is third-party testing and sharing test results to ensure the sea moss does not have high levels of metals, such as lead and mercury.”

Texture and Taste

If you’re not a fan of seaweed in general, you might find sea moss difficult to swallow. It has a slimy texture and tastes briny like the ocean. You can avoid this by incorporating the ingredient into other foods, like smoothies, to mask the taste.

Inflammation and Cancer

Sea moss contains carrageenan, which the FDA has cleared for use as an emulsifier, thickener and stabilizer in processed foods. There have been reports that it causes inflammation in the intestines, though it is unclear how. Degraded, carrageenan becomes poligeenan, which, according to the USDA, has caused ulcers in animal studies. Therefore, it is considered a human carcinogen. Notwithstanding, there isn’t any literature that proves the body can break down carrageenan into poligeenan, though, so until research says otherwise, there’s no need to panic.

While it remains unclear if sea moss is really going to make a noticeable difference to our health, Young adds that there’s no harm in trying it in small doses. “It’s concentrated as a supplement, so you don’t want to take too much,” she notes.

Sea moss comes in three forms: powdered, gel and raw. If you use it raw, the moss needs to be washed and soaked in water for at least 12 hours for it to rehydrate. Koll recommends adding it to juices, tea or smoothies to mask the taste and texture, noting that the recommended serving is one to two tablespoons. Note that sea moss is not recommended for women who are pregnant or breastfeeding, because no research has been conducted on how it interacts with a fetus or newborn’s system. And, of course, always consult with your medical provider before making any significant dietary changes.