Sea Moss Is Everywhere—But Should You Actually Be Taking It?

Sea moss supplements are flooding social media feeds and health food stores, promising everything from better gut health to stronger immunity. But while this red algae does contain valuable nutrients, the scientific evidence supporting most health claims remains surprisingly thin, and taking too much could actually backfire on your health.

What Makes Sea Moss So Popular?

Sea moss, also known as Irish moss, is a type of red algae harvested along the Atlantic coast. It has a mild fishy taste and shows up in everything from ice cream to smoothies, where other ingredients help mask the flavor. The supplement industry has embraced it in gel, powder, and capsule forms, marketing it as a nutrient-dense superfood.

"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. Most of the touted benefits actually come from studies on seaweed in general, not sea moss specifically.

What Nutrients Does Sea Moss Actually Provide?

Despite the limited research, sea moss does offer some legitimate nutritional value. It's an excellent source of iodine, which your thyroid needs to produce hormones. Some types contain several micrograms of iodine per gram, though exact amounts vary widely depending on the species and where it's grown.

Sea moss also contains several other essential nutrients:

• Calcium: Important for bone health and muscle function
• Magnesium: Supports nerve function and energy production
• Potassium: Helps regulate blood pressure and heart rhythm
• Iron: Essential for oxygen transport in blood
• Zinc: Supports immune function and wound healing

The algae is also high in fiber, which acts as a prebiotic to feed beneficial gut bacteria. This fiber content might support weight management, though more research is needed to confirm sea moss's specific benefits.

Why Too Much Sea Moss Could Harm Your Thyroid?

Here's where things get tricky: sea moss's high iodine content can be both a benefit and a risk. Adults need about 150 micrograms of iodine daily, but the tolerable upper limit is 1,100 micrograms per day. Exceeding this amount can trigger thyroid problems, including hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid).

"People who have thyroid disease should use caution when increasing their iodine from sea moss or other foods and supplements with iodine," warns Dr. Wood. If you take thyroid medications like levothyroxine, sea moss could interfere with your treatment by altering your iodine levels.

The problem gets worse because sea moss supplements aren't regulated by the Food and Drug Administration (FDA), so quality and iodine content can vary dramatically between products. "The labeling on sea moss products for iodine is not always accurate, which makes it difficult to determine the actual amount," explains Dr. Wood.

Should You Avoid Sea Moss Entirely?

Sea moss isn't necessarily dangerous for everyone, but it requires careful consideration. Pregnant and breastfeeding women should avoid sea moss supplements entirely due to unpredictable iodine levels and potential contaminants. Children shouldn't take it either because of the high iodine content.

Sea moss can also accumulate heavy metals like arsenic, lead, cadmium, and mercury from ocean water. These contaminants have been linked to serious health problems including dementia, cancer, and reproductive issues.

If you decide to try sea moss, Dr. Wood recommends starting small with 1 to 3 grams of dried sea moss added to foods like smoothies rather than taking high-dose capsules. "Taking sea moss is not foundational to health," she notes. "Moderation is essential since it's possible to overdo it on iodine."

For most people, getting iodine from iodized salt or a standard multivitamin is safer and more predictable than relying on sea moss supplements. The trendy algae might be everywhere, but that doesn't mean it belongs in everyone's daily routine.