uses JavaScript to provide the best possible experience for our content, but your browser has it disabled. Learn how to enable it here.


Search term may appear only in full report available to members. Join now for full access.

CL Answer

Which supplements can help treat anemia? Do any supplements cause a low red blood cell count?

Find out which vitamin and nutrient supplements can help prevent and treat anemia in people who are nutrient deficient and learn which supplements may cause low blood cell counts, especially when used in excess.

Woman holding various vitamins and supplements in her hands

Product Review

Iron Supplements Review (Iron Pills, Liquids and Chews)

See Which Iron Supplements Are CL's Top Picks for Different Needs

Clinical Update


COVID Vaccine and Anemia

Should people with anemia get vaccinated?

Product Review

B Vitamin Supplements Review (B Complexes, B6, B12, Biotin, Folate, Niacin, Riboflavin & More)

See Which B Vitamins Are ConsumerLab's Top Picks!

Review of B Vitamin Supplements

CL Answer

Which is the best pulse oximeter for home use?

Best pulse oximeter for home use (COVID-19, asthma and COPD). Differences between home use and FDA-approved medical pulse oximeters.

Best Pulse Oximeter for Home Use -- Pulse Oximeter

CL Answer

Is it true that taking turmeric/curcumin with food can reduce iron absorption from food?

Learn more about how to take turmeric/curcumin and if they limit iron absorption from food.

Turmeric and Iron Absorption

Product Review

Vision Supplements Review (with Lutein, Zeaxanthin & AREDS2 Formulas)

Find the Best Vision Supplement Based Our Tests

CL Answer

What is lactoferrin and will it really strengthen my immune system?

Info about lactoferrin supplements, clinical evidence for strengthening the immune system, preventing or treating colds, gut health and treating H.

What is Lactoferrin? -- lactoferrin capsules and bottle

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.

Supplements to Improve Energy and Decrease Fatigue -- tired woman yawning at desk

CL Answer

Risks of Too Many Vitamins & Supplements

Taking too many vitamin supplements -- or taking too much of a particular supplement -- can have short and long-term adverse effects.

Too Many Vitamins

CL Answer

I take warfarin (Coumadin), an anticoagulant drug. Are there supplements I should avoid, or be taking, due to this drug?

Find out which supplements should be avoided when taking blood thinners (anticoagulants) like warfarin (Coumadin), including vitamin K, St. John's wort, and curcumin.

Warfarin Supplement Interactions -- bottle of pink warfarin tablets

CL Answer

Which dietary supplements, health foods or spices contain high levels of lead?

Information about lead and heavy metals in vitamins, supplements and foods. Information on the adverse effects of lead.

Lead in Supplements & Foods -- concerned woman looking at pill

Clinical Update


Fibromyalgia Risk With Iron Deficiency Anemia?

A recent study suggests a link between iron deficiency anemia and fibromyalgia, particularly in women. Get the details in the What It Does section of our Iron Supplements Review. Also see our Top Picks among iron supplements.

Clinical Update


Home Pulse Oximeters for anemia?

We recently reported that use of inexpensive home pulse oximeters may reduce the risk of death in people with COVID. But are they useful for other conditions, such as anemia? A member recently asked us about this. Find out in our updated answer the the question: Which is the best pulse oximeter for home use? which includes our Top Picks among home pulse oximeters.

Clinical Update


Resveratrol and Anemia

A CL member recently reported developing mild iron deficiency anemia after use of a popular resveratrol supplement. Find out what research suggests about this connection in the Concerns and Cautions section of our Resveratrol review.

Clinical Update


Aspirin & Anemia Risk

Taking daily, low-dose aspirin may increase the risk of iron-deficiency anemia in older men and women, according to a recent study. Get the details in our Iron Supplements Review.

Also see our Top Picks among iron supplements.

Clinical Update


Trouble Swallowing & Iron Deficiency

Although uncommon, be aware that iron-deficiency anemia can make swallowing difficult for some people. Get the details, including if iron supplementation can help correct this symptom, in the Iron Deficiency and Anemia section of our Iron Supplements Review, which includes our Top Picks for iron.

Also see: 7 Tips to Avoid Getting a Pill Stuck in Your Throat.

CL Answer

Do any supplements or foods benefit people with Crohn's disease? Are there any supplements that should be avoided?

Find out the most common vitamin and mineral deficiencies in people with Crohn's disease, including iron, B6, B12, vitamin D, zinc and others, plus evidence for N-acetyl-glucosamine (NAG), fish oil, and curcumin.

Supplements for Crohn's Disease -- Crohn's Disease Written on Notepad, Pills

CL Answer

What is C15:0 fatty acid (found in fatty15), and does it have health benefits?

C15:0 fatty acid in fatty15 is promoted for “healthier hair & skin, balanced metabolism, and deeper sleep,” as well as “slowing the aging process.” Find out if it works.

Bottle of fatty15 with white background

CL Answer

Do any supplements help for ulcerative colitis?

Find out what supplements & vitamins can help with ulcerative colitis, such as VSL#3, curcumin, aloe or boswellia.

Woman Grabbing Stomach Due To Abdominal Discomfort

CL Answer

How do the COVID-19 vaccines compare in terms of efficacy, safety and side effects? How, when and where do I get the COVID-19 vaccine?

Find out how the COVID-19 vaccines from Pfizer and Moderna compare and learn how when and where you can get the COVID-19 vaccine.

Older woman getting an injection

Clinical Update


New Top Pick for Vision

We have tested and chosen a new Top Pick among supplements to slow the progression of age-related macular degeneration. Get the details. Also, be aware that some formulas contain too much zinc, which has been reported to cause anemia.

Clinical Update


Fatty15 for Anemia?

Is there clinical evidence that the supplement fatty15 optimizes red cell production? See our article about fatty15 (C15:0 fatty acid).

Clinical Update


Iron Supplements and Blood Tests

Should iron supplements be stopped before blood tests to monitor anemia? Find out in the ConsumerTips section of our Iron Supplements Review. Also see our Top Picks among iron supplements.

Clinical Update


How to Take Iron

New research suggests the best way to take iron to treat iron-deficiency anemia. Get the details in our Iron Supplements Review, which includes our Top Picks among iron supplements.

Clinical Update


Grape Seed Extract and Iron

Be aware that grape seed extract may affect iron levels in the body. For details, see our Iron Supplements Review, which includes our Top Picks for iron.

Also see: Which supplements can help treat anemia? Do any supplements cause a low red blood cell count?

Clinical Update


Stomach Damage from Iron Pills

Be aware that high-dose oral iron pills can sometimes damage the lining of the stomach and cause bleeding -- which can actually worsen anemia. Learn about recently reported cases, and what formulation of iron may reduce this risk, in the Concerns and Cautions section of our Iron Supplements Review.

Clinical Update


Caution With Vitamin Supplements

A woman who, for years, had taken a popular vision supplement developed anemia and low white blood cell and platelet counts. What was the connection? Find out in the Concerns and Cautions section of our Vision Supplements Review. Also see our Top Picks among vision supplements.

Clinical Update


Feeling fatigued? Iron may help

It's well known that fatigue can result from iron-deficiency anemia, but new research shows that some women who are not anemic can also benefit from iron. Women ages 18 to 53 with unexplained fatigue given iron experienced a nearly 50% reduction in fatigue in a recently published study. Get details about the treatment (including the dosage, duration, and type of iron supplement used) in the update to the Iron Supplements Review, which includes our tests of iron supplements similar to that used in this study. More >>

Clinical Update


Best Iron?

Contrary to expectations, a study which compared the effectiveness of two forms of iron in treating anemia in young children found ferrous sulfate to be more effective than a newer form of iron. For details about this, the different forms of iron, how to take iron, and our tests and comparisons of brands of iron supplements, see the Iron Supplements Review >>

Clinical Update


Signs of B12 Deficiency

B12 deficiency is not uncommon, most often affecting older people. Symptoms include anemia, fatigue, tingling in the arms and legs and loss of balance -- but a recent case report highlights a lesser-known sign of B12 deficiency. Find out more, plus how much B12 you should get in the "B12" section of the B Vitamins Review >> (Also see our Top Picks for vitamin B12 and other B vitamins.)

CL Answer

Which vitamins and supplements should be stopped before getting blood work and laboratory tests?

Find out which vitamins and supplements can interfere with blood, urine or stool tests, and imaginging tests. Learn how B vitamins such as biotin, niacin and riboflavin, as well as calcium supplements, St. John’s wort, vitamin C, and others supplements can affect test results, as well as common foods that may interfere with tests.

Vitamin & Supplements to Stop Before Blood Tests

CL Answer

What is the ingredient zeolite I see in Natural Cellular Defense and other detox supplements? Does it help in any way?

Learn what zeolite is and why it is found in many detox supplements like Waiora's Natural Cellular Defense, Get Healthy Again Zeolite, and Ultra Liquid Zeolite.

Natural Cellular Defense

Product Review

Multivitamin and Multimineral Supplements Review

Best Multivitamins In 2023 -- Caution with Gummies

Recalls & Warnings

August 16, 2023

FDA Warns Hekma Center, LLC for Promoting Products to Treat Anemia, Diabetes, Depression, & More

On June 2, 2023, the FDA issued a warning letter to Hekma Center, LLC following review of the company’s website and social media, which found statements about the company’s Natural Supplements for Anemia, Lymf (Galium aparine), Natural Supplements for Cardiomyopathy, Magic1 (Moringa ...

CL Answer

What is vitamin B12 and how much do I need?

Vitamin B12 dosage varies depending on your age, gender, and various other factors. Our CL Answer explains why B12 is important, the recommended dosages, deficiency, health benefits, and the best form.

Vitamin B12 Dosage, Benefits, Uses & Deficiency -- B12 Bottle and Tablets

CL Answer

What are the benefits of grape seed extract?

Learn about the health benefits of grape seed extract, and find out it improves venous insufficiency, leg swelling, swelling after surgery, or can help to lower blood pressure.

Benefits of Grape Seed Extract -- grapes and seeds

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.

Trace Minerals - What are they and do you need them?

CL Answer

What is desiccated beef liver? What is it used for, and is it safe?

Description of desiccated beef liver, including what it is used for, its nutrient content, and safety concerns.

Beef liver powder

CL Answer

I thought the B vitamins were all water soluble and did not build up in the body, so you would not build up toxic levels. Am I wrong?

Learn more about water-soluble B vitamins including niacin, B6, B12 and folic acid, and why taking too much of these vitamins can be toxic. See the symptoms of overdose and toxicity from B vitamins.'s answer explains.

B Vitamins

CL Answer

Does Gynostemma pentaphyllum really work as an AMPK activator and help for diabetes, high cholesterol, or weight loss?

Find out if Gynostemma pentaphyllum ( jiaogulan) works as an AMPK activator and helps to lower blood sugar and treat diabetes.'s answer explains.

Jiaogulan (Gynostemma pentaphyllum) -- Gynostemma herb and capsules

CL Answer

Are There Supplements That Help Treat POTS (Postural Orthostatic Tachycardia Syndrome)?

Find out which supplements and lifestyle changes may be helpful for people with Postural Orthostatic Tachycardia Syndrome (POTS).


CL Answer

What are the health benefits of luteolin, and is it safe?

Find out if luteolin, a compound found in many fruits and vegetables, is beneficial for cancer, heart health, skin aging, age-related cognitive decline, and other conditions, and learn if it's safe.

Luteolin containing vegetables including celery peppers lettuce and spinach

Product Review

Zinc Supplements and Lozenges Review

Find the Best Zinc Supplements and Lozenges. Have a Cold? See CL's Top Picks Among Zinc Supplements and Lozenges.

Zinc Supplements and Lozenges Reviewed by

Product Review

Quercetin & Rutin Supplements Review

Quality's a Concern With Quercetin and Rutin Supplements -- Only 17% of Claimed Amount In One

CL Answer

Can any supplements reverse gray hair?

Nearly 75% of adults aged 45 to 65 are affected by gray hair. Learn about what causes gray hair and find out if any supplements can help.

A young woman shows gray hair on her head on a white background

Recalls & Warnings

February 22, 2024

Herbalife Shake & Protein Drink Mix, Aloe, Linked With Case of Liver Injury

A 13-year-old boy in Texas developed liver failure and hepatitis-associated aplastic anemia after consuming two Herbalife products and an aloe vera beverage over a period of months, according to a report published on February 12, 2024 in the Journal of Pediatric Gastroenterology and ...

Product Review

Vitamin C Supplements Review

Find the Best Vitamin C Supplements

Vitamin C Review 2023

CL Answer

What are the health benefits of green tea, and is it safe?

ConsumerLab explains green tea's potential health benefits for everything from fighting cancer to helping your heart.

Cup of green tea with dried tea leaves

News Release

December 09, 2014

Round-up of Recent Product Tests by -- Results for B Vitamin Supplements & Energy Drinks, Garlic, NAC (N-acetyl cysteine), Iron and Omega-7 Fatty Acids

White Plains, New York, December 9, 2014 — In recent months, has published test results for a variety of popular supplements, including B vitamins supplements and energy drinks, NAC (N-acetyl cysteine), iron and garlic. In addition, ConsumerLab.

Product Review

Turmeric and Curcumin Supplements and Spices Review

See Our Top Picks Among Turmeric Products

Product Review

Fruits, Veggies, and Other Greens Supplements Review (Including Spirulina and Chlorella)

Avoid Lead in Greens, Problems with Pills, and Don't Give Up Eating Whole Foods.

Greens Review Oct 2023

Product Review

Green Tea Review: Tea Bags, Matcha Powders, and Supplements

Some green teas provide barely any green tea polyphenols, while some others are high strength. See the Test Results and Our Top Picks for Green Tea.

Green Tea Review 2024

CL Answer

Does cat’s claw have any health benefits and is it safe?

Cat's claw is promoted for numerous conditions, including arthritis (including osteoarthritis and rheumatoid arthritis), Alzheimer's disease, viral infections, boosting immune response to vaccination, and reducing side effects of chemotherapy. Find out if it works and if it's safe.

Cats claw extract capsules in a bowl on a table

CL Answer

8 Supplements That May Help Treat Peptic Ulcers – And Some to Avoid

Peptic ulcers caused by H. pylori infection are typically treated with antibiotics, but certain supplements may also help. Find out which 8 supplements might be beneficial - and which should be avoided.

Supplements for peptic ulcer disease - young man with stomachache

CL Answer

Which supplements are important after bariatric surgery (i.e., weight loss or stomach-reducing surgery)? Are there any I should avoid?

Find out which supplements may help after weight loss or stomach reducing surgery, including iron and calcium, and which should be avoided.

Bypass Surgery Sign

CL Answer

Can biotin supplements really strengthen nails or improve hair? Can other supplements help?

Learn more about strengthening brittle nails with vitamin B-7 (biotin), based on clinical evidence.

Supplements for Brittle Nails -- healthy nails

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.

Bottle of Perque Bone Guard Forte

News Release

March 30, 2011 finds 100-fold variation in cost of iron supplements

WHITE PLAINS, NEW YORK — MARCH 28, 2011 — announced today that the cost to get an equivalent dose of iron from supplements varies by more than 100-fold. A 25 mg dose of iron can cost as little as two cents or over two dollars, depending on the product.

Recalls & Warnings

November 06, 2023

FDA Warns Consumers Not to Use Dr. Ergin’s SugarMD Advanced Glucose Support, Found to Contain Prescription Drugs

On November 3, 2023, the FDA warned consumers not to purchase or use Dr. Ergin’s SugarMD Advanced Glucose Support products after FDA laboratory analysis found the supplement to contain glyburide and metformin.

Recalls & Warnings

November 09, 2023

FDA Warns Biorica International for Cholesterol, Kidney & Cancer Claims

On August 4, 2023, the FDA issued a Warning Letter to Biorica International Corp. following review of the company’s websites and social media, which found statements about the company’s Plaquex Oral Supplements to be drug claims, which are not permitted for dietary supplements.

News Release

March 31, 2009 Warns of Problems with Multivitamins and Vitamin Water -- Defects Found in Over 30% of Supplements Selected for Testing; Several Popular Children's Multis Exceed Tolerable Upper Intake Levels

WHITE PLAINS, NEW YORK — MARCH 31, 2009 — Over 30% of multivitamins recently selected for testing by were found to contain significantly more or less ingredient than claimed or were contaminated with lead.

News Release

May 05, 2008

Some iron supplements short on iron or contaminated according to

WHITE PLAINS, NEW YORK — May 5, 2008 — announced today that two iron supplements failed to pass recent independent testing. One "high potency" iron supplement contained only 37% of it claimed iron. ConsumerLab.

News Release

September 10, 2007

Tests of B-vitamins by finds several short on folic acid — New report covers B-complexes, thiamin, niacin, B-6, B-12, biotin and folic acid supplements

WHITE PLAINS, NEW YORK — SEPTEMBER 10, 2007 — Half of the B-complex supplements recently selected by for testing were found to lack the total claimed amounts of folic acid, an essential nutrient also known as vitamin B-9.

Recalls & Warnings

October 15, 2007

US Marshalls Seize Charantea Supplements Promoted for Diabetes, Anemia and Hypertension

At the request of the U.S. Food and Drug Administration (FDA), on October 9, 2007, U.S. Marshals seized approximately $71,000 of goods from FulLife Natural Options, Inc., of Boca Raton, Fla., which marketed and distributed Charantea Ampalaya Capsules and Charantea Ampalaya Tea.

Recalls & Warnings

June 26, 2006

FDA Warns Candy Maker Making Heart Health Claims

On May 31, 2006, the U.S.

Recalls & Warnings

April 17, 2018

FDA Warns Seller of Echinacea, Iron, Aloe Supplements & More for Manufacturing Violations

On March 30, 2018, the FDA issued a warning letter to Ozark Country Herbs following a facility inspection which found a number of the company's products, including Echinacea-Goldenseal, Natural Iron, and Aloe-Vera Goldenseal Salve, to be adulterated because they were prepared, packed, or held under ...

Recalls & Warnings

October 18, 2017

FDA Warns Seller of Arthritis, Blood Pressure, Diabetes Supplements For Making Drug Claims

On August 15, 2017, the FDA issued a warning letter to Years to Your Health, Inc., following an inspection of the company's website which found a number of their products to be misbranded, as they contained drug claims.

News Release

January 19, 2007

Consumers warned of problems with multivitamins — uncovers defects in over half of products tested

WHITE PLAINS, NEW YORK — JANUARY 19, 2007 — Fifty-two percent of multivitamins recently selected for testing by were found to be contaminated with lead, unable properly break apart, or to contain significantly more or less ingredient than claimed.

News Release

January 03, 2006

Tests of memory enhancing supplements by reveals lead in some ginkgo

WESTCHESTER COUNTY, NEW YORK — TUESDAY, JANUARY 3, 2006 — In its new test report on Memory Enhancement Supplements, has revealed finding significant amounts of lead in certain products on the market.

News Release

July 26, 2004 reports on iron supplements — Wide variety of products pass testing; Consumers advised on proper dose, type of iron to avoid problems

WHITE PLAINS, NY — Monday, July 26, 2004 — announced today that fifteen iron supplements passed its recent independent testing but it cautioned that large differences among products require consumers to choose products carefully.

News Release

July 16, 2002 finds lead contamination remains a problem for certain mineral supplements — Lead found in iron, magnesium and, most recently, potassium pills

WHITE PLAINS, NY — July 16, 2002 — announced today that its testing has shown that approximately 5% to 10 % of certain mineral supplements are contaminated with lead. The findings are based on ConsumerLab.

News Release

October 03, 2001

Most iron supplements pass testing — Lead contamination and insufficient iron found in some

WHITE PLAINS, NY — October 3, 2001 —, an independent evaluator of dietary supplements and nutrition products, released results today of its Product Review of Iron Supplements. Iron deficiency is the most common cause of anemia in the U.S. and worldwide.

Recalls & Warnings

March 28, 2011

Dangerously High Levels of Vitamins A and D in Product Prompt FDA Warning

On March 28, the U.S. FDA warned consumers to stop using Soladek, a vitamin-solution product marketed by Indo Pharma, S.A., of the Dominican Republic, because the product may contain dangerously high levels of vitamins A and D.

Recalls & Warnings

November 01, 2013

Protein Shakes Containing Prescription Drug Pose Serious Health Risk

On November 1, 2013, Health Canada warned consumers that Vega One Vanilla Chai (sizes 437g and 874g) and Vega Sport Performance Chocolate nutritional shakes, by Sequel Naturals Ltd., have been found to contain the prescription antibiotic chloramphenicol.

Recalls & Warnings

October 12, 2013

Metagenics Enzyme Supplement Recalled Due To Drug Risk

On October 11, 2013, Metagenics Canada issued a voluntary recall of digestive enzyme supplement Spectrazyme, due to potential contamination with the prescription antibiotic chloramphenicol.

Recalls & Warnings

October 11, 2013

Prebiotic and Digestive Enzyme Supplement Recalled Due To Drug Risk

On October 10, 2013, Adeeva Nutritionals Inc. issued a voluntary recall of digestive supplement Flora Essentials due to potential contamination with the prescription antibiotic chloramphenicol.

Recalls & Warnings

January 24, 2013

Excessive Lead and Mercury Found In Chinese Herbal Supplements

On January 23, 2013, Health Canada warned consumers that certain batches of the Chinese dietary supplements [W.S.

Recalls & Warnings

June 22, 2011

Recall of Calcium & Magnesium Softgels Containing Excessive and Potentially Toxic Amounts of Vitamin D

On or about June 7, 2011, NOW Foods announced the following recall to retailers. was subsequently made aware of the recall by a member.

Recalls & Warnings

May 06, 2015

Joint Pain Supplements Found to Contain Diuretics, Antihistamines and Other Undeclared Drugs

On May 4, 2015, the FDA warned consumers not to buy or use the following supplements promoted for joint or back pain because they were found to contain undeclared drugs. Each was identified during an examination of international mail shipments.  

Recalls & Warnings

October 21, 2014

Seller of Weight Loss, Saw Palmetto Supplements and More Warned for Drug Claims

On October 9, 2014, the FDA issued a warning letter to Bethel Nutritional Consulting, Inc., following a review of the company's website which found statements made about 15 Day Detox Diet, Alpha Lipoic Acid. 300 mg.