Best Sea Moss in the UK (2026): Compared by What Each Brand Discloses, Not Hype
The best sea moss for most people in the UK is Double Wood Irish Sea Moss: two capsules give 1,200 mg of Irish moss extract, and it is the only one we found on Amazon.co.uk whose brand posts a lab report for a batch. People eat sea moss for its minerals; human studies are few. With a thyroid condition or pregnancy, ask your doctor first.
By Erin Rose Updated October 19, 2026 How we chose
Our pick for most people
Double Wood Irish Sea Moss
1,200 mg Irish moss extract · 2 capsules · 120 capsules
The only active ingredient is an Irish moss (Chondrus crispus) extract, with no bladderwrack. Double Wood posts a lab report for batch 2601602: lead was 0.355 mcg a serving, under its limit of 0.5, with total arsenic, cadmium and mercury also tested. The report does not name the lab and gives no iodine number. Double Wood prices only in dollars on its own store, so we show no pound price.
Which sea moss is right for you?
Want to know how much iodine you get?
Erbology Organic Irish Sea Moss Powder is organic Irish moss from Ireland. The brand lists 11,200 mcg of iodine per 100 g, so a quarter-teaspoon serving (about 1 g) holds about 112 mcg, under the 150 mcg adults need a day and well under the 600 mcg European limit. It costs £0.29 a day at the brand’s UK price. The brand says it tests for heavy metals but posts no report.
Erbology Organic Irish Sea Moss Powder
£0.29 a day · about 112 mcg iodine
Want a plain capsule from Ireland?
Each Emerald Isle Seaweed Organic Irish Sea Moss Capsules capsule holds 500 mg of dried Irish moss, with no other seaweed. The brand lists 200 to 300 parts per million of iodine in the seaweed, about 100 to 150 mcg a capsule. It costs £0.21 a capsule at the brand’s UK price. The brand says a UKAS-accredited lab tests it but posts no report.
Emerald Isle Seaweed Organic Irish Sea Moss Capsules
£0.21 a capsule · 500 mg
Sea moss on Amazon.co.uk we compared
| Sea moss | Cost a day | Why it is or is not a pick |
|---|---|---|
| Double Wood Irish Sea Moss | Brand prices in dollars | Our pick: lab report for a batch |
| Erbology Organic Irish Sea Moss Powder | £0.29 | Lists iodine; no report |
| Emerald Isle Seaweed Organic Irish Sea Moss Capsules | £0.21 | Plain Irish moss; no report |
How we chose
We searched Amazon.co.uk for sea moss with a UK postcode on October 19, 2026, opened each likely product, and read the brand’s own label, iodine figures and lab reports. We rank by the testing each brand shows, then a named seaweed, then cost at the brand’s own UK price. We left out blends with bladderwrack and burdock. No sea moss is on a public testing list we hold.
Ask your doctor first if you have a thyroid condition, take thyroid medicine, or are pregnant or breastfeeding. In Europe the upper limit for adults is 600 mcg of iodine a day from all sources (EFSA); the US limit is 1,100 mcg (NIH). What to check on a sea moss label.
Questions people ask
What is the best sea moss to buy in the UK?
Double Wood Irish Sea Moss, for most people. It is Irish moss extract in capsules, and Double Wood posts a lab report for heavy metals in its batch. If you want an iodine number, Erbology Organic Irish Sea Moss Powder lists one.
How much iodine is in sea moss?
It varies a lot from batch to batch, and most labels give no number. Erbology lists about 112 mcg in a quarter teaspoon. The European upper limit for adults is 600 mcg a day (EFSA). More on sea moss safety.
Are sea moss gummies or 16-in-1 blends worth it?
Not for most people. Many add bladderwrack, a brown seaweed usually higher in iodine, and burdock, and the sea moss amount is often an “equivalent” number. What a sea moss gummy really holds.