Sea moss is showing up everywhere — from foods like ice cream, yogurt and soups to sea moss supplements in gel, powder and capsule form. Social media regularly highlights the benefits of sea moss and celebrates it as a superfood. But is there any proof to the hype?

Health Benefits of Sea Moss

Sea moss has been used throughout the centuries, but it’s most recently in the spotlight for several health claims, including that it can improve gut health, immunity and heart health. But most of these claims come from studies on seaweed, not specifically sea moss.

“High-quality evidence that supports health benefits and claims about sea moss is limited,” says Mary Ella Blair Wood, DO, an integrative medicine physician at Northwestern Medicine.

More research is needed to confirm its health benefits, but sea moss is a good source of some essential vitamins and minerals.

Excellent source of iodine

Although exact amounts vary by species and growing waters, sea moss is high in iodine. Some types of red seaweed have several micrograms (mcg) of iodine per gram.

Iodine is important because it helps make thyroid hormone. But too much iodine from sea moss or other supplements with iodine can cause thyroid problems like hypothyroidism (an underactive thyroid) or hyperthyroidism (an overactive thyroid), so it’s important to not take too much iodine.

“People who have thyroid disease should use caution when increasing their iodine from sea moss or other foods and supplements with iodine,” says Dr. Wood.

Source of other vitamins and minerals

Sea moss contains several other vitamins and minerals, including:

• Calcium
• Magnesium
• Potassium
• Iron
• Zinc

Sea moss is also known for its high fiber content. The fiber in sea moss acts as a prebiotic, which feeds good gut bacteria. Added fiber can support weight loss, but more research is needed to confirm the specific benefits from sea moss.

How Much Sea Moss Should You Take?

Dr. Wood says there is no standardized or evidence-based daily dose for sea moss because there is such a wide range of species. How it’s sourced and processed varies, too, which could impact quality. It’s worth noting that in the United States, dietary supplements — including sea moss supplements — are not approved by the U.S. Food and Drug Administration (FDA), so quality can vary.

Form also matters. Sea moss gel is diluted, so it usually delivers fewer minerals per serving than dried powder or capsules, which are typically more concentrated.

If you do decide to take sea moss supplements, “prioritize brands that clearly identify species and how it’s sourced, as well as provide heavy‑metal testing and batch-specific certificates of analysis,” says Dr. Wood.

Special considerations for taking too much iodine

Because the amount of iodine in sea moss supplements varies widely, keep total iodine near the recommended dietary allowance for adults, which is 150 mcg per day, and below the tolerable upper limit, which is 1,100 mcg per day. Taking more than that can increase your risk of developing a thyroid problem.

“Safety guidance should be based on your total amount of daily iodine. The labeling on sea moss products for iodine is not always accurate, which makes it difficult to determine the actual amount. Only use products that clearly label the amount of iodine and provide batch-specific testing,” says Dr. Wood.

If you are pregnant or breastfeeding, you need more iodine (220 mcg per day during pregnancy and 290 mcg per day while breastfeeding), but it’s important not to exceed these recommended amounts.

“Taking sea moss supplements during pregnancy or while breastfeeding is not recommended because the amount of iodine in supplements is unpredictable and because of potential contaminants found in sea moss,” says Dr. Wood. “From a risk-benefit standpoint, I generally recommend avoiding sea moss. Clinical guidelines recommend getting iodine through iodized salt and prenatal vitamins that have a standardized amount of iodine.”

Additionally, if you follow a plant-based diet, focus on iodized salt or other food sources of iodine instead of supplements. And because it’s high in iodine, avoid giving sea moss to children.

Sea Moss Side Effects

In addition to the development of thyroid problems, other potential side effects from taking sea moss include:

• Digestive discomfort, including bloating and diarrhea
• An allergic reaction, especially if you’re allergic to seafood
• Medication interactions. Talk to your doctor before trying sea moss if you take any of these medications:
• Thyroid medications
• Because of its high amount of iodine, sea moss can affect thyroid medications like levothyroxine and antithyroid medications.
• Dr. Wood says: “If you take a thyroid medication, before starting sea moss, ask your doctor to order a lab test to get your baseline thyroid level. Then have a follow-up lab test to see if your levels have changed. I recommend testing thyroid levels six to eight weeks after starting sea moss since taking additional iodine can alter your medication dosage.”
• Diabetes medications
• The fiber in sea moss can help support how your body regulates insulin.
• Dr. Wood says: “People with diabetes should monitor their blood sugar levels more closely when taking sea moss because the added fiber may influence their sensitivity to insulin.”
• High blood pressure medications
• Sea moss is high in potassium, and blood pressure medications can affect potassium levels.
• Dr. Wood says: “If you take medication for high blood pressure, monitor your blood pressure at home when you first start taking sea moss.”
• Anticoagulants (blood thinners)
• The vitamin K in sea moss may interact with these medications.
• Dr. Wood says: “If you take a blood thinner, especially warfarin, you should be closely monitored because ingredients in supplements can vary widely.”

Other Considerations

Before adding sea moss to your routine, there are a few more things to keep in mind.

Quality and contaminant risks

Sea moss can accumulate heavy metals (known as contaminants), such as:

• Arsenic
• Lead
• Cadmium
• Mercury

Heavy metals in food have been linked to a host of health problems, including dementia, cancer and reproductive issues.

The connection between sea moss and carrageenan

In foods, sea moss is primarily used for its carrageenan — a common food additive that helps thicken milk products like ice cream and is found in many processed foods. Carrageenan is a fiber extracted from red seaweed and is FDA‑approved, but its safety has been widely debated.

Food‑grade carrageenan is generally recognized as safe, but some forms of it have been linked to issues with gastrointestinal health. If carrageenan causes digestive issues, especially if you have irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD), choose foods without it.

How To Include Sea Moss in Your Diet

“Taking sea moss is not foundational to health,” says Dr. Wood. “If you decide to use it, small amounts added to foods like smoothies is preferred over taking high-dose capsules or gels. Moderation is essential since it’s possible to overdo it on iodine.”

To help manage the amount of iodine you get from sea moss, start small with 1 to 3 grams of dried sea moss. Before eating it, rinse and soak raw sea moss thoroughly. Dr. Wood advises against combining sea moss with other foods and supplements that contain iodine unless your doctor has reviewed how much iodine you get daily.

Talk with your physician or a registered dietitian to see if adding sea moss to your diet makes sense for you, especially if you have thyroid disease, are pregnant or breastfeeding, or are taking prescription medications.