Sea moss is a type of sea algae that people may add to food or take as a nutritional supplement. Sea moss benefits may include supporting the immune system, thyroid function, and hair and skin health.

In this article, we will discuss the nutritional information of sea moss, how to prepare it, and any potential benefits and side effects.

Ground covered in beige-colored sea moss.Share on Pinterest
Egmont Strigl/Getty Images Caption: Tundra floor covered with Irish Moss (Chondrus crispus)

Sea moss typically refers to a specific type of algae or seaweed called Chondrus crispus, also known as Irish moss. It is a spiny, edible plant, and has some similarities to other edible seaweeds such as kombu, dulse, or wakame.

Sea moss grows naturally in waters and tide pools along rocky coasts, such as coasts of the northern Atlantic Ocean. Common sea moss is a red seaweed, though it can grow in different colors as well, depending on factors such as the local climate and water temperatures.

According to the U.S. Department of Agriculture (USDA) FoodData Central, 2 tablespoons (tbsp) or a 10 gram (g) serving of sea moss contains approximately:

  • calories: 4.9
  • protein: 0.2 g
  • fat: 0 g
  • carbohydrates: 1.2 g
  • sugars: 0.1 g

The same serving of sea moss also contains these vitamins and minerals:

  • calcium: 7.2 milligrams (mg)
  • magnesium: 14.4 mg
  • phosphorous: 15.7 mg
  • potassium: 6.3 mg
  • iron: 0.9 mg
  • zinc: 0.2 mg
  • copper: 0.02 mg
  • manganese: 0.04 mg

Red seaweeds also have antioxidant properties, which may help prevent oxidative damage in the cells.

Similar to other sea vegetables, sea moss is a natural source of the mineral iodine. Research posted to the Journal of Medicinal Food notes that sea moss contains about 47 mg of iodine per gram.

Sea moss has a history of use in cultures close to where the moss naturally grows. Sea moss is a natural source of a thickener called carrageenan. This can make it a good addition to soups, stews, or other foods that need thickening.

Some companies still harvest and sell the dried sea moss itself, but it is more common to find sea moss in the form of a dietary supplement.

Supplements may contain sea moss on its own, or with a combination of other ingredients. The sea moss is usually in powdered or gel form.

Some companies may take advantage of the thickening properties of sea moss to create products such as vitamin gummies or gels.

Sea moss may have the same benefits as other types of sea algae, as they share similar compounds.

However, the current research into sea moss has limitations, and scientists still need further evidence to back any health claims. Those include:

Supporting weight loss

Seaweeds may help support weight loss. In a 12-week study of 78 adults, those who took 1,000 milligrams of red seaweed extract per day had a significant reduction in total body fat mass and body weight than the placebo group.

Research posted to Marine Drugs also notes that a compound in many seaweeds called fucoxanthin shows promise in helping to break down and metabolize fat.

Weight loss effects may vary with each type of seaweed, and much of the research focuses on isolated compounds, rather than the effects of sea moss generally.

Supporting thyroid health

Diets rich in iodine may support thyroid health. The thyroid needs this mineral to create and use important hormones in the body. Without enough iodine, the thyroid may not function properly and could cause metabolic issues.

As a natural source of iodine, types of sea algae such as sea moss may help prevent iodine deficiency.

Supporting gut health

Sea moss may have prebiotic effects which could play a role in improving the health of the gut microbiome.

Research posted to BMC Complementary Medicine and Therapies notes that sea moss is rich in dietary fiber and oligosaccharides such as carrageenan. The sea moss seemed to support gut health by feeding the healthy bacteria in the intestines.

This was an animal study, though. Researchers would need to do further human studies to support these findings.

Supporting immune health

The gut relates to the immune system. A diet rich in prebiotic, fiber-rich foods such as sea moss may help promote a healthy immune system.

Research posted to BMC Complementary Medicine and Therapiesfound higher levels of immune antibodies in rats who had eaten sea moss. Further research in humans could help support these findings.

Helping in the fight against cancer

Compounds in some algae may help fight against specific cancers. Research posted to Cancers notes that fucoxanthin, found abundantly in some algae, may help fight against specific markers of colorectal cancer or reduce risk factors.

With this said, the research focused heavily on high concentrations and extracts of fucoxanthin. More research into sea moss itself could show if the same benefits apply.

Having neuroprotective effects

Antioxidant properties in algae may help protect against neurodegenerative disease. Research posted to Marine Drugs found that an extract from sea moss protected against markers of Parkinson’s disease.

Researchers carried out the study on roundworms. Further research in humans would help explore the potential neuroprotective effects of sea moss on humans.

Supporting muscle and energy recovery

Sea moss may play a role in helping the body recover from workouts or help relieve fatigue.

A study in the Asian Journal of Medical Sciences involved 80 adults over the age of 40 with musculoskeletal symptoms. The research found that people given certain types of sea moss had reduced fatigue, exhaustion, and pain levels. This may be due to the high levels of amino acids and total proteins present in the plant.

Supporting fertility

There is not much formal research to back up the claim that sea moss will promote fertility. Sea moss may make up part of fertility treatment in traditional medicinal systems, and anecdotally some people claim the algae helps their fertility. More formal research is needed to evaluate this claim.

Supporting healthy hair and skin

Some anecdotally claim that taking sea moss regularly improves the look and feel of their skin and hair. Researchers need more evidence to support this claim.

There are some possible downsides or side effects from eating sea moss.

Even in supplement form, the nutritional content, and therefore potential benefits, from sea moss can vary. Factors such as growing region, temperature, and minerals in the water may affect the nutrient levels in sea moss.

Varying levels of iodine in sea moss may also put a person at risk for iodine deficiency if sea moss is the person’s only source of iodine.

Some people who eat large quantities of sea moss or other seaweeds that are very rich in iodine may get too much iodine in their diet. Overconsumption of iodine may put a person at risk for iodine poisoning or thyroid problems.

Contamination may be another potential risk for seaweeds such as iodine. Seaweed and algae may accumulate minerals and metals from the environment. If there are heavy metals in the area, they may be in the algae as well.

Sea moss lends itself well to a number of recipes and ways of preparation.

Sea moss in a raw, dried form can help thicken soups and stews.

Making a sea moss gel is a useful way to add sea moss to the diet. Using dried sea moss, soak the sea moss in water overnight. Rinse the sea moss off, and add it to a blender with clean water. Blend the mixture until smooth, and store it in a covered container. Put the covered mixture in the refrigerator to gel overnight.

This gelled mixture makes a simple addition to foods that need thickening, or people can eat it as a supplement. The shelf life will vary based on factors such as storing temperature and cleanliness of the preparation tools.

People can also add powdered sea moss to juices and smoothies and sprinkle it over yogurt or cereal. Adding powdered sea moss to soups or stews may have a similar thickening effect as using it in gel form.

Sea moss is a spiny sea vegetable similar to other forms of seaweed. It may have similar health benefits to other types of seaweed. Traditionally harvested for its carrageenan, it also contains varying levels of healthy minerals and antioxidants.

Further research on sea moss, particularly in humans, will help evaluate current health claims about the product.

People can easily add dried, powdered, or gelled sea moss into their diet, or take as a supplement. If people have an existing thyroid problem, they should check with their healthcare provider before taking it due to the iodine content in sea moss.