“Sea moss contains 92 of the 102 minerals your body needs.”
Your body does not need 102 minerals; US health guidance lists about 15, and sea moss supplies only some of them in amounts that vary.
Sea moss is a seaweed with some useful minerals, but it is not a complete mineral source, and no human study backs its health claims. A varied diet covers the minerals your body needs, and sea moss can add more iodine than you want.
If you buy sea moss, choose one that names the seaweed species on the label and shows third-party testing for heavy metals.
Safety note: Too much iodine, more than about 1 milligram a day, can harm the thyroid, and the iodine in seaweed products varies widely. In a 2026 study of 66 sea moss products sold online in the US, arsenic, cobalt and mercury were detected in dried sea moss, and some products carried germs such as Salmonella. The study summary does not say whether the metal levels were above safety limits. Excess iodine from seaweed eaten by nursing mothers has slowed the thyroid in breastfed babies, so sea moss should be avoided while breastfeeding unless its iodine and heavy metal levels are known to be low.
Talk to a healthcare professional if: you have a thyroid condition, you are pregnant or breastfeeding, or you plan to take sea moss every day.
The list of minerals the body needs is well settled, and it has about 15 entries, not 102. Sea moss does contain some of them, but no source backs the 92-of-102 figure.
Your body does not need 102 minerals; US health guidance lists about 15, and sea moss supplies only some of them in amounts that vary. MedlinePlus, from the National Library of Medicine, lists seven minerals you need in larger amounts (calcium, phosphorus, magnesium, sodium, potassium, chloride and sulfur) and eight you need in small amounts (iron, manganese, copper, iodine, zinc, cobalt, fluoride and selenium). Most people get enough of them from a varied diet.
Sea moss, also called Irish moss (Chondrus crispus), is a red seaweed. Seaweeds eaten as food contain minerals such as iron, magnesium and zinc. But the mineral content of sea moss changes a lot with the conditions it grows in, and the US military's supplement safety program found that human research testing sea moss supplement claims is lacking.
Seaweed can carry much more iodine than people expect. In a study of 96 seaweed foods and supplements, one portion of whole seaweed held anywhere from 128 to 62,400 micrograms of iodine, and for 54 of the products a single portion or dose went over the safe upper limit. Labels often listed the seaweed or its iodine content wrongly or not at all. The kelps tested were the highest; the study did not single out sea moss.
- MedlinePlus, National Library of Medicine. Minerals. Health topic page
- Operation Supplement Safety (Consortium for Health and Military Performance, Uniformed Services University). Sea Moss in Dietary Supplements. Published 15 November 2021
- Drugs and Lactation Database (LactMed). Sea Moss. National Institute of Child Health and Human Development; 2006-. PMID: 41730053
- Aakre I, Solli DD, Markhus MW, Maehre HK, Dahl L, Henjum S, Alexander J, Korneliussen PA, Madsen L, Kjellevold M. Commercially available kelp and seaweed products: valuable iodine source or risk of excess intake? Food & Nutrition Research. 2021;65:7584. DOI: 10.29219/fnr.v65.7584. PMID: 33889064
- Rejuso A, Cobo M, Curran JE, Wang R, Humiston G, Worobo R, Vegdahl AC. Microbial and Heavy Metal Analyses of Commercially Available Sea Moss and Sea Moss Products. Journal of Food Protection. 2026;89(11):100915. DOI: 10.1016/j.jfp.2026.100915. PMID: 42710593