Reviews and Information for Iodine (from Kelp)
Kelp (Supplements)
Find the best kelp supplements, see how much iodine popular kelp supplements contain and other tests of quality. Find out how iodine from kelp supplements can affect thyroid hormones if kelp supplements can increase energy and help for weight loss. Plus information about safety, side effects, and potential drug interactions.
Kelp (Supplements) Review
Filters
View All
Search term may appear only in full report available to members. Join now for full access.
Product Review
Seaweed Snacks and Foods Review
Tests Reveal Seaweed Snack Risks
Product Review
Potassium Iodide (KI) and Iodate (KIO3) Radioprotective Pills Review
Learn How to Choose the Best Radioprotective Iodine Pill and Use It Properly
CL Answer
Which supplements can cause diarrhea?
Can supplements like magnesium cause diarrhea? Find out which supplements may cause diarrhea, such as vitamin B12, curcumin, magnesium, vitamin C and fish oil.
CL Answer
Is it true that iodine can cause acne or other skin problems?
Information on iodine causing acne and other skin problems such as rashes and hives. ConsumerLab.com's answer explains.
CL Answer
Dietary Supplements and Herbs to Avoid When Breastfeeding
Find out which supplements should be avoided when breastfeeding, including medicinal herbs, soy, and flaxseed.
Product Review
Multivitamin and Multimineral Supplements Review
32% Failed our Tests. Choose Your Multivitamin Carefully.
CL Answer
Himalayan and Sea Salts: Health Benefits, Toxic Metals, & Microplastics
Himalayan salt health benefits, along with other gourmet salts like Hawaiian and Mediterranean. Info including what's in them and their safety.
CL Answer
Do hair loss supplements, such as Viviscal, Hair La Vie, and Nutrafol, or topical essential oils work?
Vitamins and supplements that may help with hair loss and thinning, including saw palmetto, beta-sitosterol, protein, iron, and vitamin D.
CL Answer
Top 8 vitamins and nutrients for vegetarians and vegans
Find out which 8 supplements may be needed by vegetarians or vegans to meet all their daily nutrient requirements and learn ways to find supplements that do not contain ingredients objectionable to people following vegetarian or vegan diets.
CL Answer
Which vitamins and supplements are good for acne, and are there any that make it worse?
Information about supplements for acne and clearer skin. Plus, find out which vitamins and supplements can make acne worse.
Product Review
Vitamin K Supplements Review (Including Calcium, Vitamin D, Magnesium & Boron)
Find Out If It's Worth Taking Vitamin K and Which Products Are Best
Clinical Update
1/28/2018
A Case of Too Much Iodine
A woman with hypothyroidism was hospitalized due to a change in mental state and physical symptoms resulting from getting too much iodine from iodine-containing supplements. For details and upper limits for iodine intake, see the Concerns and Cautions section of the Kelp Supplements Review.
Clinical Update
10/25/2022
Can Foods Cause Iodine Deficiency?
A CL Member asked if foods could interfere with iodine absorption. The answer is yes, although this is not likely, as we explain in the Preventing/treating iodine deficiency section of our Kelp Supplements Review.
Product Review
Potassium Supplements Review
Be Careful with Potassium Supplements! Problems Found. Tests and Reviews of Potassium Supplements & CL's Top Picks.
CL Answer
What are trace minerals and do I need them?
Trace minerals include boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, zinc, and others. Find out what they do, how much of each trace mineral you should be getting, and who's most likely to be deficient in these minerals.
CL Answer
Which supplements help to improve energy and decrease fatigue?
Energy supplements and vitamins - Some can help increase energy and reduce fatigue, including CoQ10, curcumin/turmeric, cocoa, and B vitamins.
CL Answer
All About Thyroid Supplements & Desiccated Thyroid Extract (Armour Thyroid)
Learn about supplement ingredients such as iodine, selenium, zinc, acetyl-l-carnitine, ashwagandha and guggul used for thyroid conditions and find out if they are beneficial. Also learn why ingredients such as alpha-lipoic acid, soy, resveratrol, quercetin may impair thyroid function.
CL Answer
What is Perque Bone Guard Forté? It is safe and effective for bone health?
Find out about the ingredients in Perque Bone Guard Forté, including which ingredients may be beneficial for osteoporosis and bone health and which may be a safety concern.
CL Answer
Do sea moss and carrageenan have health benefits? Are there risks?
Sea moss is promoted for thyroid health, boosting immunity, improving gut health, and other uses. Find out if it works and learn about possible side effects of sea moss and its constituent, carrageenan.
Clinical Update
11/03/2025
Kelp & Bone Loss
Overconsumption of kelp could speed up bone loss. Learn why in our Kelp Supplements Review, which includes our Top Pick among kelp supplements.
Clinical Update
11/09/2021
Caution With Seaweed Salts
Seaweed salts (also known as seaweed seasoning, kelp granules, or table kelp) can be used as salt substitutes, but cooking with them may result in the formation of toxic byproducts according to a recent study. Get the details in the Concerns and Cautions section of our Kelp Supplements Review.
CL Answer
I take levothyroxine (Synthroid), a thyroid hormone to treat hypothyroidism. Are there supplements or foods I should avoid, or be taking, due to this drug?
Is taking certain supplements and hypothyroidism medications bad? Learn which supplements can interact with thyroid hormone medications like levothyroxine (Synthroid), thyroid hormone levels, and laboratory tests.
Clinical Update
5/14/2024
Plant-Based Milks: Iodine Concern
Be aware that almond, oat, and soy milk tend to contain very little iodine compared to cow’s milk, which could increase the risk of iodine deficiency and thyroid problems in people who do not get enough iodine from other sources. Get the details in the Concerns and Cautions section of our Plant-Based Milks Review. This is particularly important for women who are pregnant or breastfeeding – due to increased iodine requirements, see our Top Pick prenatal multivitamin for more details.
Also see: Top 8 vitamins and nutrients for vegetarians and vegans
CL Answer
Does WEEM Grow Hair and Is It Worth It?
WEEM Hair.Skin.Nails is marketed as a "clinically tested hair health blend.” Find out if it — or its ingredients — works for hair loss and if it's worth the price.
News Release
November 02, 2023
Spirulina and “Greens” Supplement Tests Show Some Problems
White Plains, New York, November 2, 2023 — ConsumerLab tests of spirulina, chlorella, and “greens” supplements revealed that tablets of three brands of spirulina failed to disintegrate within the allotted time, and several other products contained amounts of lead unsuitable for regular consumption ...
News Release
February 09, 2022
Caution With Spirulina Supplements: ConsumerLab Tests Reveal Lead Contamination, Quality Concerns
White Plains, New York, February 9, 2022 — Problems were discovered in three out of four spirulina supplements recently tested by ConsumerLab. One product was found to be contaminated with lead, and two other products, which were tablets, failed to disintegrate within the expected time.
Clinical Update
9/29/2023
Iodine From Seaweed
Is iodine from seaweed absorbed as well as iodine from iodine pills? Find out in the What It Does section of our Seaweed Snacks and Foods Review. Also see our Top Pick among seaweed snacks.
Clinical Update
10/01/2017
Paleo Diet and Iodine
The "Paleo" diet excludes table salt and dairy products, which are sources of iodine. A recent study investigated whether or not this causes iodine deficiency (which is also a concern with a vegan diet). Get the details in the "Iodine" section of the Multivitamin/Multimineral Supplements Review >>
Clinical Update
8/05/2012
Be Careful with Iodine -- Especially If You're Pregnant
Unlike over-the-counter medicines, dietary supplements are generally not required to carry warning labels, even if they contain toxic amounts of ingredients. If you don't know how much of a vitamin, mineral, or other ingredient you really need, it's easily possible to get too much. This is what seems to have happened to some pregnant women taking a widely-sold iodine supplement, according to a recent medical report. Just one tablet contained 57 times the daily iodine they needed and more than ten times the limit associated with increased risk of toxicity. Their children were born with congenital hypothyroidism, apparently due to getting too much iodine from their mothers.
Find out which product these women took in the updated Iodine section of the Multivitamin Supplements Review. You'll also find appropriate levels of other vitamins and minerals and see which products in the Review did or did not exceed tolerable intake levels of vitamins and minerals. More >>
Clinical Update
3/18/2022
Iodine Pills for Radiation Protection
Due to concerns relating to the safety of nuclear reactors and potential use of nuclear weapons in the war in Ukraine, demand for radioprotective iodine products has jumped.
Potassium iodide and potassium iodate can help protect the thyroid from the effects of radioactive iodine from the air, water, and foods after a nuclear event. But who should be taking these products, when should they be taken, and how much should be taken?
Find out in our review of Potassium Iodide and Iodate Radioprotective Pills, and see our Top Picks among products (and where to currently get them).
Clinical Update
12/01/2025
Iodine in Multivitamins
People with hyperthyroid conditions like Graves’ disease may need to avoid multivitamins with iodine, as highlighted in a recent report. Get the details in the Iodine section of our Multivitamin and Multimineral Supplements Review, which includes our Top Picks among multivitamins.
CL Answer
Is it better to take fish oil, flaxseed oil -- or both?
Fish oil and flaxseed oil -- how they are different, what they are used for, if and how they can help with arthritis, depression, lowering cholesterol & more.
CL Answer
Can prenatal vitamins have too much folic acid? Mine has 800 mcg, but isn't that more than what's recommended? Is this dangerous to me or my baby?
Is it possible for prenatal vitamins to have too much folic acid? Find out the correct dosage so that it is not dangerous to babies.
CL Answer
Grüns Gummies: What’s In Them, Do They Work, and Are They Safe?
Find out what's in Grüns Superfoods Greens Gummies, if they work, and if they are safe. Get ConsumerLab's take on these gummy vitamins with added fiber and powdered fruit and vegetables.
Clinical Update
5/30/2014
Not Enough Iodine in Prenatal Supplements
There is growing concern about inadequate iodine intake among pregnant and nursing mothers. Find out how much should be taken as a supplement -- and which vitamins do or don't have it -- in the update to the Multivitamin and Multimineral Supplements Review >>
CL Answer
Do Sugar Bear Hair Vitamins make hair shine, nails stronger, and help both to grow? They taste good but are super expensive.
Info on Sugar Bear Hair vitamins. Do they make hair shine, nails stronger and help hair and nails grow? ConsumerLab.com's answer explains.
CL Answer
What are "broad-spectrum micronutrient" supplements, and do they have greater health benefits than multivitamin/multimineral supplements?
Learn about "broad-spectrum micronutrients" and how they compare to multivitamin/multimineral supplements.
Clinical Update
10/07/2024
Seaweed for Vegetarians
Eating a serving of nori, a type of seaweed, can improve vitamin B-12 status among vegetarians. Seaweed can also provide iodine. But there are caveats. Get the details in our Seaweed Snacks and Foods Review, which includes our Top Pick among seaweed snacks.
Also see: Top 8 vitamins and nutrients for vegetarians and vegans
Clinical Update
11/20/2025
Thyroid Risk With Sea Moss
Be aware that sea moss supplements can contain substantial amounts of iodine, which, in excess, can pose a risk to people with certain thyroid conditions. Get the details in our article about sea moss.
Recalls & Warnings
June 30, 2013
Warning Over Excessive Iodine Intake From Supplements, Including Kelp
On June 5, 2013, the American Thyroid Association (ATA) advised that children and adults, including pregnant and lactating women, consume no more than 500 mcg of iodine daily from iodine and kelp supplements.
News Release
December 20, 2021
Dangerous Amounts of Iodine, Toxic Heavy Metals Found in Some Seaweed Snacks, According to ConsumerLab Tests
White Plains, New York, December 20, 2021 — Dried or roasted seaweed has become a popular snack, providing a tasy, crunchy, and vegan-friendly source of protein, fiber, and iodine, an essential nutrient for proper thyroid function.
News Release
April 25, 2017
Caution with Kelp Supplements: May Contain Too Much Iodine
White Plains, New York, April 25, 2017 — Kelp supplements are promoted as a natural source of iodine, an important mineral for healthy thyroid function. But are they a good alternative to regular iodine supplements? To find out, ConsumerLab.
Recalls & Warnings
June 13, 2024
Thyroid Supplement Recalled Due to Salmonella
On June 11, 2024, Penn Herb Company Ltd issued a recall of 51 bottles of Nature’s Wonderland Thyroid Formula capsules after FDA testing revealed the products to be contaminated with Salmonella.
News Release
August 08, 2016
ConsumerLab Finds Lead, Cadmium and Arsenic Contamination in Greens and Whole Foods Supplements
White Plains, New York, August 9, 2016 — Powders, pills and drinks made from ingredients like wheat grass, alfalfa, kelp, spirulina, chlorella, leafy vegetables and fruits are a popular choice for people looking to increase their intake of vitamins, minerals and other plant-based nutrients.
News Release
January 12, 2016
Problems Found with 32% of Multivitamin/Multimineral Supplements -- ConsumerLab.com Identifies Good Choices for Men, Women, and Children
White Plains, New York, January 12, 2016 — You can't always judge a supplement by its label -- or by its price, according to a new report from ConsumerLab.com, which recently tested dozens of multivitamin/multimineral supplements.
News Release
July 08, 2013
Contamination a Common Problem in "Greens" and "Whole Foods" Products According to ConsumerLab.com
White Plains, New York — July 8, 2013 — "Greens" and "whole foods" powders and pills, made from wheat grass, alfalfa, kelp, spirulina, leafy vegetables and other chlorophyll-containing ingredients, as well as fruits, were recently tested by ConsumerLab.
News Release
August 31, 2012
ConsumerLab.com tests selenium supplements -- Finds one with less than 25% of listed amount
White Plains, New York, August 31, 2012 — ConsumerLab.com announced results today of its Product Review of Selenium Supplements. Among the supplements selected by ConsumerLab.com for testing, one was found to contain only 23.
News Release
June 09, 2010
ConsumerLab.com tests "greens" and "whole foods" products; Most offer healthful nutrients, but some found contaminated with heavy metals
WHITE PLAINS, NEW YORK — JUNE 9, 2010 — "Greens" powders, made from wheat grass, alfalfa, kelp, spirulina, leafy vegetables and other chlorophyll-containing ingredients, were recently tested by ConsumerLab.com for potential contamination with heavy metals and pesticides. ConsumerLab.
News Release
June 25, 2002
ConsumerLab.com reviews radioprotective Iodine pills in response to terrorist threats — Quality of products is high, but local access is poor
WHITE PLAINS, NY — June 25, 2002 — In response to the threat of terrorist attacks on U.S. nuclear facilities, ConsumerLab.com, an evaluator of health and nutrition products, today released a Product Review of Potassium Iodide/Potassium Iodate (Radioprotective Agents).
News Release
April 16, 2002
ConsumerLab.com finds "Breast Enhancement" pills lack evidence of efficacy
WHITE PLAINS, NY — April 16, 2002 — ConsumerLab.com announced today that it found no hard evidence to suggest that current dietary supplements marketed for breast enhancement are effective.
Recalls & Warnings
June 07, 2017
FDA Warns Seller of Probiotic and Omega-3 Supplements for Manufacturing Violations
On May 22, 2017, the FDA issued a warning letter to BioTE Medical, LLC following a facility inspection which found its products, including BioTE DIM, BiotTE Probiotic, BioTE Iodine Plus, and BioTE Omega 3 to be adulterated because they were prepared, packed, or held under ...
Recalls & Warnings
January 23, 2014
Many Thyroid Supplements Contain Thyroid Hormones -- Risk of Thyrotoxicosis
A recent study found that 9 out of 10 supplements marketed for "thyroid support" and purchased at retail stores or on the Internet contained actual thyroid hormones thyroxine (T4) and/or triiodothyronine (T3), posing a risk to consumers.
Recalls & Warnings
September 21, 2023
Moor Herbs, Inc Warned for Manufacturing Violations, Drug Claims
On August 1, 2023, the FDA issued a Warning Letter to Moor Herbs, Inc.
Recalls & Warnings
April 23, 2013
Seller of Digestion, Thyroid and Vitamin D Supplements Warned For Drug Claims
On November 5, 2012, the FDA issued a warning letter to The Women's Health Institute at Texas following a review of the company's various websites which found statements made about Digest + SEB, Iodine Plus 2, and D5000 Vitamin D dietary supplements to be drug claims.
Recalls & Warnings
February 22, 2012
Baby Vitamin Recalled for Excessive Iodine
Shaklee Corporation recently recalled two lots of Shakleebaby Multivitamin & Multimineral powder for containing iodine in excess of the amount labeled, according to a news item dated January 30, 2012 on the Shaklee website.
Recalls & Warnings
May 10, 2013
Maker of Concentration, Pain, Immune, Cholesterol Supplements Warned For Drug Claims
On April 24, 2013, the FDA issued a warning letter to EuroPharma Co., Inc., following a review of the company's website which found statements made about Calm Kids, CholestCaps, CuraMed 375 mg, CuraMed 750 mg, Curamin, Mental Advantage, Tri-Iodine, and Viragen to be drug claims.
Recalls & Warnings
June 24, 2014
CELLFOOD Recalled in Canada
On June 23, 2014, Health Canada recalled CELLFOOD (Nu Science), a supplement promoted for improved energy, endurance and natural health, because it was found to be an unauthorized health product.
Recalls & Warnings
December 16, 2013
Weight Loss Capsules Recalled Due Allergen Risk
On December 13, 2013, Stone Independent Research, Inc. issued recall of one lot of Zanocap Scientific Weight Loss 500 mg capsules because they contain undeclared whey protein, which is derived from milk.
Recalls & Warnings
July 12, 2013
Herbal Supplement Company Warned For Drug Claims, Manufacturing Violations
On June 18, 2013, the FDA issued a warning letter to Herbs of Light, Inc.
Recalls & Warnings
June 20, 2020
FTC Warns 30 More Companies for Coronavirus Claims
On June 18, 2020, the FTC announced that it sent warning letters to 30 companies for selling products such as immune system boosters, colloidal silver, vitamin C, and CBD with unsupported claims that they can treat coronavirus (COVID-19).
Recalls & Warnings
May 23, 2020
FTC Warns 50 More Companies for Coronavirus Claims
On May 21, 2020, the FTC announced that it sent warning letters to 50 companies for selling products such as herbal products, immune system boosters, and vitamin C, with unsupported claims that they can treat coronavirus (COVID-19).
Recalls & Warnings
July 18, 2018
Maker of Vitamin B12 and Multimineral Supplements Warned by FDA
On July 6, 2018, the FDA issued a warning letter to Aegle Nutrition, LLC, following a facility inspection which found some of the company's products, including Tropical Oasis Ionized Trace Minerals, Tropical Oasis Ultra Methyl B12, and Tropical Oasis Premium Vitamin B12 to be ...
Recalls & Warnings
July 11, 2017
FDA Warns Dr. Carolyn Dean of Drug Claims Made for Magnesium, Calcium & Other Mineral Supplements
On June 27, 2017, the FDA issued a Warning Letter to Dr. Carolyn Dean of New Capstone, Inc.
Recalls & Warnings
January 24, 2013
Food for Health Warned for Manufacturing Violations and Drug Claims on Supplements
On October 5, 2012, the FDA issued a warning letter to Food for Health International, LLC following a facility inspection which found the company's products, including Activz brand Vitamin D, Potassium Iodine, Organic Vitamin C, Whole 9 (a fruit and vegetable meal replacement shake) Control and VMA ...
