Sea moss is the latest superfood supplement making waves in the wellness ecosphere. Athletes such as Cristiano Ronaldo, and Lionel Messi, and actor Michael B. Jordan are just a few examples of big names who swear by seaweed’s nutrient-dense profile. And for good reason, sea moss (a type of seaweed) is believed to promote fertility and heart health. But is there scientific evidence to back up these alleged sea moss benefits for men?
In case you’re wondering what the heck sea moss (or Irish moss) even is, it’s an edible red algae that grows on rocky outposts along the Atlantic coastlines of Europe and North America (1). You’ve swallowed microscopic amounts of the algae before without knowing it: Sea moss is naturally rich in carrageenan, a food stabilizing additive added to commercial food products, such as nut-based milk and Greek yogurt (2, 3).
In stores and online, sea moss comes in gel, liquid, gummy, or powder forms—though taking it isn’t going to magically turn you into a professional soccer player or ripped actor.
From a nutrition perspective, sea moss or Irish moss is pretty overhyped, says registered dietitian Courtney Pelitera, R.D. “Like many ‘superfoods,’ the magic is all in the marketing,” she says. In other words, sea moss won’t make you healthier just on its own.
Before you go out and buy a $40 jar of sea moss gel, here’s what nutrition experts want you to know.
About the Experts
Courtney Pelitera, M.S., R.D.N., is a registered dietitian who works with athletes from high school up to the professional level. She is the founder at Devour Your Life Nutrition LLC.
Elizabeth Sergeant, A.Nutr., AFMCP, is a registered nutritionist and functional medicine practitioner. She is the founder and CEO of Well Nourished Club.
Potential Sea Moss Benefits
Many species of seaweeds are good sources of vitamins, essential minerals, dietary fiber, essential amino acids and polyphenols, which have antioxidant and anti-inflammatory properties (4). However, research specifically on the benefits of sea moss isn’t as robust as it is for other types.
Registered nutritionist and functional medicine practitioner Elizabeth Sergeant says, “while sea moss is a good source of beneficial nutrients such as folate, iron, zinc, potassium, and magnesium” there are minimal scientific studies to suggest it will have life-changing effects (such as feeling more energized and smarter) as many social media influencers, rappers, and celebrities suggest.
That said, those who follow a vegan or vegetarian diet may benefit from a daily serving of sea moss, Pelitera says. “It’s a natural source of vitamin B12, which is often difficult to find in plant foods,” she says.
Here’s what a growing body of research suggests sea moss could be capable of in the human body. Of course, it’s always a good idea to touch base with your healthcare provider before adding any supplement to your stack.
May Help Lower Cholesterol
“Certain articles cite a study about sea moss having cholesterol-lowering effects,” says Sergeant. That’d be a boon, considering 32 percent of adult men have high cholesterol, a condition which puts them at risk for coronary artery disease (5). “However, the original study seems to have been done on Ulva rigida (6), a type of sea lettuce.” Sea moss may not have the same effect.
Still, “sea moss does contain a specific type of soluble fiber called carrageenan, which a few small studies suggest (7) may lower cholesterol levels,” she adds. Keep in mind this research is a bit dated, so take that with a grain of salt.
May Support Gut Health
Eating adequate fiber daily can help prevent constipation and, in the long run, colorectal cancer. Yet only four percent of men in the U.S. meet daily fiber recommendations (8). Not only does a healthy gut improve digestion, but it also supports immune function, mood, and cognition (9).
“The fiber and certain compounds in sea moss may support a healthy gut microbiome,” says Sergeant. “However, research on the gut health benefits of sea moss is scarce.” Not to mention, there is less than one gram of fiber in just two tablespoons of sea moss (10). Other gut-healthy supplements are backed by stronger evidence.
To make matters even more confusing, some older studies suggest that carrageenan may increase gut inflammation (11). But, the link between the two isn’t definitive and requires more research.
May Boost Fertility
Sperm count is famously on the decline: In the last 50 years, men’s total sperm count decreased by about 62 percent (12). One small study showed that red seaweed (sea moss) enhanced sperm motility in male albino rats, which might increase their fertility (13). It also showed that rats treated with sea moss experienced a nearly 37 percent increase in sperm, compared to those that weren’t treated.
Granted, there isn’t equivalent research on humans. However, many men in the Caribbean islands believe sea moss has “bedroom benefits,” which may be due to its rich concentration of nutrients like zinc.
One study suggests taking 250 milligrams (mg) of zinc per day can boost testosterone levels after just six weeks (14), which can support fertility efforts. Keep in mind the study was done on men with chronic renal failure who were undergoing hemodialysis. Also, that dose of zinc is more than 20 times the recommended daily amount (15).
The real kicker? Two tablespoons of raw sea moss has less than 1 mg of zinc (10).
MORE GUT HEALTH
Sea Moss Side Effects
As with many things in life, more isn’t always better—and that includes an extra helping of sea moss. There are a few reasons not to add sea moss supplements to your daily diet.
May negatively affect thyroid health
“Sea moss contains high amounts of iodine, which can affect thyroid function,” says Pelitera. Iodine is necessary for hormone production, but most men get enough through their diet.
Iodine deficiency is uncommon in the U.S., and many endocrinologists advise against taking iodine supplements unless prescribed by your healthcare provider (16, 17). The National Institutes of Health suggests high iodine intake can cause thyroid gland inflammation and, in the absolute worst case, cancer (16). Those with hyper- or hypothyroidism should steer clear.
Can mess with blood thinners
Sea moss (like many leafy green veggies) contains vitamin K (10), which can pose a problem for some men.
If you have AFib or another heart condition—or if you’re at increased risk for stroke—you may be on a blood thinner, which helps treat and prevent blood clots. Warfarin (also known as Coumadin), is a common blood thinner that alters vitamin K metabolism, as the vitamin helps with blood clot formation (18, 19).
Generally, when taking a medication like Warfarin you’ll want to keep your vitamin K intake low and consistent (20). “If you’re on a blood thinner you should probably avoid adding this supplement,” Pelitera says.
Final Verdict: Is Sea Moss Worth It?
While sea moss contains nutrients like zinc, magnesium, and folate, experts agree you’re better off skipping sea moss supplements and just eating nutrient-dense foods.
“The amount of vitamins and minerals you’d get in a single serving isn’t enough to give you a significant boost,” Sergeant says. “I would take the $40 the sea moss supplement would cost and put it right toward my grocery bill.”
Pelitera concurs, and adds, “if you do decide to take a supplement, make sure you are getting it from a trusted, reliable source.”
Unlike prescription medications, supplements aren’t FDA-regulated, which means that manufacturers are not required by law to prove the efficacy or safety of their products (21). Make sure any product you purchase is third-party, independently tested to make sure you’re getting what the label indicates. “This designation will be right on the packaging,” Pelitera says.
Also, similar to seaweed, “sea moss may contain trace amounts of heavy metals (22) like aluminum, mercury, or lead, depending on where it’s grown, or if it’s lab-grown versus harvested,” Pelitera adds. Heavy metals occur naturally in many foods in very small amounts, but higher concentrations can be toxic to the brain, kidneys, or nervous system (23). The idea here is to not overdo sea moss, knowing it contains certain metals that could potentially be stored in the body over time.
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- Heart Disease and Stroke Statistics—2023 Update: A Report From the American Heart Association.
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- Review of harmful gastrointestinal effects of carrageenan in animal experiments.
- Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected globally in the 20th and 21st centuries.
- The effect of Red Seaweed (Chondrus crispus) on the fertility of male albino rats.
- Impact of oral zinc therapy on the level of sex hormones in male patients on hemodialysis.
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- Iodine Fact Sheet for Consumers.
- What Are The Benefits of Sea Moss?
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- Warfarin alters vitamin K metabolism: a surprising mechanism of VKORC1 uncoupling necessitates an additional reductase.
- Warfarin Diet: What food should I avoid?
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- Heavy metals and potential risks in edible seaweed on the market in Italy.
- Heavy metals contamination and associated health risks in food webs—a review focuses on food safety and environmental sustainability in Bangladesh.
