- How much iodine is in sea moss? We measured ours.
It's the question almost every sea moss brand dodges, and it's the one that matters most. Sea moss is a seaweed, and seaweeds concentrate iodine from the ocean. So a fair customer question is simple: how much iodine am I actually getting per serve?
Most product pages answer with a shrug — "rich in minerals", "nature's multivitamin" — and never a number. We think that's the wrong way round. So we sent our gels to accredited laboratories, had the results assessed by a government toxicologist, and published the lot. Here are the numbers.
The short answer
Our finished sea moss gel measured 0.66 mg/kg of iodine in the Soothing Honey Lemon & Matcha flavour and 1.1 mg/kg in the Classic Lime, tested as the gel is actually eaten. Translated into a serve:
- About 10–17 µg of iodine per 15 g serve (one scoop).
- About 20–33 µg per recommended daily amount (two tablespoons).
For context, the Australian Nutrient Reference Values set an adult Recommended Dietary Intake (RDI) of 150 µg of iodine a day, and an Upper Level of Intake of 1,100 µg a day. So a daily serve of Belo gel contributes a modest slice of your iodine needs — meaningful, but well short of the upper limit at the recommended amount.
Those finished-gel numbers, and the toxicological reading of them, were assessed by the Western Australian Department of Health in 2026. You can read the underlying reports in full on our .
This is general information, not medical advice. If you have a thyroid condition, are pregnant, or take medication, talk to your clinician before adding any new iodine source.
Why the "per serve" number is the honest one
You'll see sea moss iodine quoted two ways, and the difference matters.
Dry weight basis is the concentration in dried, powdered seaweed before it becomes anything you'd eat. Our own dry-basis testing returned 13 mg/kg of iodine (measured by NATA-accredited Mérieux NutriSciences and the National Measurement Institute, January 2026). That's a useful cross-check on the raw material — it confirms the finished-gel figures are in the right ballpark once you account for hydration — but it is not what lands in your bowl.
Finished-product basis is the gel as you actually consume it, water and all. That's the 0.66–1.1 mg/kg above. When a brand quotes only the big dry-weight number without saying so, it can make a product sound many times more concentrated than the spoonful you eat. We label ours clearly so the two never get confused.
Iodine in seaweed varies — a lot — and we won't pretend otherwise
Here's the honesty part. Iodine content in seaweed is not fixed. It swings with the species, where and when it was grown, and how it was processed.
A 2024 study in Environmental Science & Technology measured total iodine across 26 seaweed samples from four species and found a range from 52.4 to 1,322 mg/kg dry weight — a more than twenty-fold spread — and found that how much of that iodine the body can actually take up varied from 18.5% to 89%, depending on the inorganic iodine fraction and the fibre in the seaweed (Zhou et al., 2024). A separate systematic review of brown algae reached the same broad conclusion: iodine levels and bioavailability differ enormously by species and are changed by drying, soaking and cooking (Blikra et al., 2022).
Our sea moss is Kappaphycus alvarezii (commercially known as "Eucheuma cottonii", or gold sea moss) — a warm-water red seaweed that sits well below high-iodine brown kelps like kombu on the iodine scale. That biology is part of why our per-serve figures are what they are. But it also means batch-to-batch variation is real, and any brand claiming a single permanent iodine number for a natural seaweed is overselling the precision. Our published figures reflect the batches we tested; we retest, and we republish.
What "well below the upper level" actually means
The Department of Health assessment looked at our finished-gel iodine against the population Upper Level of Intake (1,100 µg/day for adults) and concluded it sits well below that limit for the general population at the recommended intake. In plain terms: at two tablespoons a day, the iodine from the gel is a supportive contribution toward the 150 µg RDI, not a megadose.
That said, iodine is one of those nutrients where both too little and too much can cause problems, and individual circumstances differ. Which brings us to the part we put on every page where iodine comes up.
Who should check with a clinician first
Sea moss is naturally rich in iodine. This product is not appropriate for individuals with hyperthyroidism. Do not exceed the recommended amount. Consult a healthcare professional before use if you are pregnant, taking medication, or have a thyroid condition.
We mean that plainly. If you have hyperthyroidism, sea moss is not the product for you. If you're pregnant, breastfeeding, on thyroid medication, or managing a thyroid condition, have the conversation with your clinician before you start — iodine needs are individual, and a professional who knows your history is the right person to weigh it.
How to sanity-check any sea moss brand's iodine claim
If you take one thing from this piece, make it a checklist you can use on anyone's product:
- Is there a number at all? "Rich in iodine" is not a number.
- Is it dry-weight or finished-product? A dry-weight figure on a gel or drink can look 15–20× bigger than what you actually consume.
- Is the number tied to a serve size? Micrograms per serve is what you can compare to the 150 µg RDI.
- Is there a lab report behind it, from an accredited lab? Ask to see it.
- Does the brand say who shouldn't use it? Honest iodine information includes the hyperthyroidism caution.
We've tried to pass our own checklist. Our per-serve iodine, the dry-basis cross-check, the arsenic and heavy-metal panels and the microbiology are all published, in full, at . If you'd like to see the gel these numbers come from, that's our .
Sea moss should be good for your belly and honest with your questions. Iodine is the question. Now you have the number.
References
- Zhou S, Zhang D, Kong Y, Zhang Q, Cui X. In Vivo Bioavailability and In Vitro Bioaccessibility of Iodine in Edible Seaweeds: Method Development and Health Implications. Environmental Science & Technology. 2024;58(51):22553–22562. doi:10.1021/acs.est.4c08990
- Blikra MJ, Henjum S, Aakre I, et al. Iodine from brown algae in human nutrition, with an emphasis on bioaccessibility, bioavailability, chemistry, and effects of processing: A systematic review. Comprehensive Reviews in Food Science and Food Safety. 2022;21(2):1517–1536. doi:10.1111/1541-4337.12918
- Food Standards Australia New Zealand. Iodine in food and iodine requirements.
- Food Standards Australia New Zealand. Survey of iodine levels in seaweed and seaweed containing products.
- National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand — Iodine.
- Australian Bureau of Statistics. Australian Health Survey: Usual Nutrient Intakes / urinary iodine (4364.0.55.006).