Before anyone gets confused, I thought I should point out that Algin and Kelp are quite different. I'm not suggesting that someone couldn't benefit from Kelp, but I do think it's important to be accurate about their vast differences.

Yes, Algin is "derived" from Kelp, but it is a single, isolated ingredient. Unlike Kelp, Algin does not contain the numerous other ingredients that Kelp does (such as iodine salts, amino acids, B-complex vitamins, vitamin K, and many trace minerals including copper and zinc). Someone who has excess levels of copper or zinc, or perhaps blood-clotting problems (for which they are taking anticoagulants), should be aware that Kelp contains copper and zinc, and vitamin K (which promotes blood clotting).

(Because I don't get iodine from Algin, I take Thyroid Support for my iodine source...and it contains Kelp.)

In comparison, Algin is a non-digestible fiber (polysaccharide). It is a single ingredient, so it doesn't contain any other ingredients. I've contacted Nature's Sunshine about the Algin we use and was told that there may be only trace amounts of iodine, if any (apparently as a residual process of extracting Algin from Kelp).

Kelp and its other ingredients are digestible, meaning they will be broken down and absorbed into the systemic circulation. Algin is a non-digestible fiber that passes through the body without being absorbed into the systemic circulation.

Kelp tablets or capsules provide only a small amount of Algin in comparison to Algin capsules. So, you'd have to take a lot of Kelp to get the same amount of Algin found in Algin-only products.

Plus, many companies do not test their seaweed products for heavy metals or other contaminants. Obviously, this might be a problem for someone with mercury toxicity.

I hope this helps clarify the differences.