Product Reviews
Kelp Supplements Review

Reviewed and edited by Tod Cooperman, M.D. Tod Cooperman, M.D.
 Initial Posting: 4/22/17 Last Update: 1/27/18 
Kelp Supplements Reviewed by

Choose the Best Kelp Supplement

Be Cautious With Kelp! Only 50% of Supplements Pass CL's Review

Alphabetical list of kelp supplement brands compared in this review
Natural Factors Liquid Kelp Progressive Laboratories Kelp Swanson Kelp
Nature's Answer Kelp Thallus Puritan's Pride Premium Sea Kelp Traditional Foods Market Kelp Powder
Nature's Life Icelandic Kelp Solgar North Atlantic Kelp Vitamin World Sea Kelp
Natural Factors Liquid Kelp Nature's Answer Kelp Thallus Nature's Life Icelandic Kelp Progressive Laboratories Kelp Solgar North Atlantic Kelp Swanson Kelp Traditional Foods Market Kelp Powder Vitamin World Sea Kelp
Make sure the kelp supplement you take passed our tests and is right for you!
Isn't your health worth it?
If you use a kelp supplement, it's important to choose carefully! Tests by revealed that half of the kelp supplements it reviewed contained approximately 200% of their listed amounts of iodine, creating a safety concern. In addition, one of these was contaminated with the toxic heavy metal arsenic.

Kelp supplements are primarily used as a source of iodine — an important mineral for healthy thyroid function. Most people get enough iodine through their diets, but those who are on a low salt diet or do not eat dairy or seafood, may be at risk for iodine deficiency. 

Fortunately, ConsumerLab also identified several high-quality kelp supplements which contained what they claimed without unacceptable contamination. One of these was chosen as CL's Top Pick among kelp supplements.

You must be a member to get the full test results along with's recommendations and quality ratings of kelp supplements. You will get results for 8 supplements — 6 selected by and two which passed the same testing through its voluntary Quality Certification Program, as well as information about one supplement similar to one that passed testing. 

In this comprehensive review, you'll discover:
    • Which kelp supplements passed and which failed our testing
    • Which kelp supplements offer the best quality and value, and which is CL's Top Pick
    • Direct comparisons and quality ratings of kelp supplements
    • Clinical evidence for what kelp supplements can and cannot do
    • How much iodine your kelp supplement should provide
    • Who should not take kelp supplements
    • Potential side-effects and concerns with kelp

If you already are a member, SIGN IN now.

Learn More About Kelp Supplements Answers -- for Kelp Supplements Review
Which dietary supplements and health foods contain high levels of lead? Get the answer >>

Which supplements help to improve energy and decrease fatigue? Get the answer >>

Is it true that iodine can cause acne or other skin problems? Get the answer >>

Which vitamins and supplements are good for acne, and are there any that make it worse? Get the answer >>
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