Sea Moss

People often come to sea moss after reading something confident online. These are the questions our naturopaths ask in store, mostly about what's actually in the tub and who should avoid it.

A good fit if

• You want a measured source of iodine and you'll buy a listed medicine rather than an imported gel
• Your thyroid is healthy and no practitioner has ever raised a concern about it
• You're not already taking kelp, bladderwrack or another seaweed, because nothing caps the total
• You're comfortable buying a traditional food product with no human trials behind it
• You want it on your skin for hydration, which is a permitted use and a much lower-risk one

Check with us first if

• You already take any seaweed product. Sea moss, kelp, bladderwrack, Ascophyllum and Laminaria each have their own cap, and the combined total isn't capped at all.
• You're pregnant or planning to be. A study of 10,736 pregnant women found 52 per cent had too much iodine, which can lead to low thyroxine, an underactive or overactive thyroid, and in newborns, high birth weight and thyroid problems.
• You're breastfeeding. The iodine target rises to 270 micrograms a day, higher than in pregnancy, and there's no sea moss data for breastfeeding.
• You've had a long history of low iodine. The reference source says you may still react badly at intakes below the upper level.
• You're buying an imported gel or bulk dried seaweed. Only a compliant Australian listed product has had its iodine measured, and iodine in seaweed varies enormously with species, harvest site and season.
• You take any prescription medicine. There's no interaction data for sea moss either way, so talk to your pharmacist rather than guessing.
• If you take prescription medicine, check with your doctor, pharmacist or our naturopaths before you start.

• Sea moss gel. Best known for: Whole seaweed soaked and blended, and the format you'll see most online. Absorption: There's no clinical study of any sea moss format. Typical use: How much iodine it has depends entirely on the batch of seaweed, and it isn't measured unless the product is a listed medicine. That's the whole risk in one sentence.
• Chondrus dry, the whole dried seaweed. Best known for: The raw material, allowed under its own Schedule 1 entry. Absorption: None established. Typical use: It has exactly the same iodine condition: under 300 micrograms per maximum recommended daily dose when taken internally.
• Chondrus extract. Best known for: Concentrated, so it may hold more iodine, weight for weight, than the raw seaweed. Absorption: None established. Typical use: The same iodine condition again. Because it's concentrated, measuring the iodine matters more, not less.
• Capsules and tablets. Best known for: The format most likely to be a listed medicine. Absorption: None established. Typical use: That makes it the format most likely to have had its iodine measured, which is the only thing Australian rules actually ask of this ingredient.
• Topical sea moss creams and masks. Best known for: Applied to the skin rather than swallowed. Absorption: Not established. Typical use: Use on the skin is allowed where the iodine concentration in the medicine, not counting salt derivatives or iodophors, is 2.5 per cent or less.
• Carrageenan. Best known for: The purified gum taken from Chondrus and used as a thickener. Absorption: Not applicable. Typical use: Allowed in Schedule 1 only as an inactive ingredient, both as carrageenan and as sodium carrageenan. A product listing it as an active ingredient doesn't comply.
• Gracilaria sold as sea moss. Best known for: A different seaweed sold under the same common name. Absorption: Not established. Typical use: Gracilaria doesn't appear in any Schedule 1 entry. If a product lists it as an active ingredient, it's worth asking how the product is regulated.
• Kelp, bladderwrack, Ascophyllum and Laminaria. Best known for: Different seaweeds with exactly the same iodine limit. Absorption: Not applicable. Typical use: Each is capped on its own at under 300 micrograms of iodine a day, and nothing in the rules caps the combined total across them.
• Wakame and sea lettuce. Best known for: Two seaweeds with completely different conditions. Absorption: Not applicable. Typical use: Wakame has no iodine condition but must not contain the holdfast (the root-like base) and is for use by mouth only. Sea lettuce is for the skin only at no more than 0.1 per cent, and not for use in the eye.

Reference values. There's no sea moss dose, because there's no sea moss trial. What we can give you is the iodine maths. The NHMRC adult iodine target is 150 µg a day for both men and women, rising to 220 µg in pregnancy and 270 µg while breastfeeding. For children, it's 90 µg from ages 1 to 8, 120 µg from 9 to 13 and 150 µg from 14 to 18. Infants have an adequate intake rather than a target: 90 µg up to six months and 110 µg up to twelve months.

Typical supplemental range. The only number Australian law sets is the limit, not a dose. A listed medicine containing Chondrus crispus, Chondrus dry or Chondrus extract must contain less than 300 micrograms of iodine per maximum recommended daily dose for products you swallow, and for products used on the skin, the iodine must be 2.5 per cent or less of the medicine. There's no cap on grams of seaweed. The cap is on the iodine it gives you. Where a product carries a pregnancy thyroid claim, it must also provide at least 150 micrograms of iodine a day, which puts it in a narrow window between 150 and just under 300.

Upper level. The NHMRC iodine upper levels are 1,100 µg a day for adults, 900 for ages 14 to 18, 600 for 9 to 13, 300 for 4 to 8 and 200 for ages 1 to 3. No upper level could be set for infants under 12 months, and the source says their iodine should come only from milk, formula and food. Compare the sea moss limit with those: a compliant adult product can give more iodine in a day than the whole upper level for a four-year-old. The source also notes that people with thyroid disorders or a long history of low iodine may still react badly at intakes below the upper level.

Worth knowing. The most useful thing to know is that there's no cap on the total when you combine products. Sea moss, kelp, bladderwrack, Ascophyllum and Laminaria each have the same iodine limit on their own, and nothing in the rules limits the total across them. If you take a gel, a kelp tablet and a bladderwrack capsule, you're combining three separately capped sources. What you need depends on your age, diet and health, so talk to one of our naturopaths.

If any of these sound like you, talk to one of our naturopaths or your doctor before you start.

• Any thyroid condition. In autoimmune thyroiditis or Graves' disease that has been treated before, the thyroid can't adjust to extra iodine the way it normally would, and an underactive thyroid (hypothyroidism) follows.
• High iodine intake over a long time. Too much iodine triggers autoimmune thyroiditis, partly because heavily iodised thyroglobulin provokes the immune system more.
• Pregnancy. Too much iodine was found in 52 per cent of 10,736 pregnant women studied, with effects on newborns including large birth size (macrosomia) and thyroid problems.
• Newborns and unborn babies. They're specifically named among those whose thyroid can't adjust to extra iodine.
• Babies 0 to 12 months. No safe upper level of iodine can be set, so iodine should come from breast milk, formula and food only.
• Children under nine. An adult product that follows the rules may supply their entire iodine upper level or more.
• A long history of low iodine. You could react badly even at intakes below the upper level.
• Taking more than one seaweed. Sea moss, kelp, bladderwrack, Ascophyllum and Laminaria are each capped on their own, and the total isn't capped.
• Imported gels and bulk dried seaweed. The iodine isn't measured, and it varies with species, harvest site and season.
• Heavy metals. Seaweeds concentrate elements from seawater, none of our sources looks at heavy metals in Chondrus crispus, and Schedule 1 sets no heavy metal condition for it. That's a missing control rather than a proven risk.
• Medicine interactions. We have no interaction data for sea moss, so ask a pharmacist rather than assuming there are none.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before you start.