Iron Supplements Review

Summary

What is It? Iron is essential to manufacture hemoglobin, which enables red blood cells to transfer oxygen to the body's tissues. It is widely available in foods including meat, fish, grains and vegetables and the average diet provides sufficient iron (See What It Is).

Symptoms of deficiency: Iron deficiency (which is treatable with iron supplements) can cause symptoms such as fatigue, shortness of breath, dizziness, headache and pale skin. It is most common in menstruating women but also is commonly seen in children and pregnant women (few men are deficient in iron, and some may be at risk for iron excess).

Iron supplementation may reduce unexplained fatigue in women of child-bearing age who are not anemic but have ferritin levels in the lower end of normal range, inhibit dry cough associated with ACE inhibitors, and help to reduce symptoms of restless leg syndrome in people with low ferritin levels (see What It Does).

Which form? Iron comes in many forms. If taken with just water, all are about equally well-absorbed, so less expensive forms, such as ferrous sulfate, are fine. However, with larger doses, some people experience gastric discomfort and/or constipation. Taking with food may reduce discomfort, but also reduces absorption of certain forms of iron, such as ferrous sulfate, while other forms are better absorbed in the presence of food, such ferrous bisglycinate and ferrous glycinate. Note that some supplements include vitamin C to increase iron absorption but this is unlikely have a significant effect, and there is concern that slow- or timed-release products may lead to reduced absorption of iron (see Forms of Iron and Avoiding Stomach Upset).

Top Pick? One product was Not Approved for failing to disintegrate within the required time (See What CL Found). Among the products that passed testing and were "Approved" for their quality, CL selected its Top Picks based on quality, cost, dose, and absorption.

How much to take? For correcting iron-deficiency anemia in adults: 100 mg to 200 mg daily, divided into two or three separate doses; this should be done only under physician supervision. When used as a treatment for other conditions, doses between 40 mg and 250 mg have been used. Unless treating a deficiency or specific condition, limit your daily intake of iron from supplements and fortified foods to no more than 45 mg to avoid side-effects and the harmful effects of excessive iron. Iron can also interfere with certain drugs. (See How much to take? and Concerns and Cautions).

Don't take iron with tea, as well as other minerals, as this may decrease iron absorption (See What to avoid when taking).

What It Is:

Iron is an essential mineral that the body requires in small amounts. It is widely available in foods including meat, poultry, and fish, as well as dried fruits, grains, and green leafy vegetables. Iron from plant sources is absorbed half as well as that from animal sources. The average diet provides about 10 to 20 mg of iron per day.

What It Does:

Iron Deficiency and Anemia
Iron is needed to manufacture hemoglobin, which enables red blood cells to transfer oxygen to the body's tissues. Severe or prolonged iron deficiency is the leading cause of anemia in the United States, affecting about five percent of women and two percent of men. Symptoms of iron deficiency anemia include easy fatigability, shortness of breath, dizziness, headache, coldness of hands and feet, pale skin, chest pain, weakness, and lethargy. Other symptoms can include brittle nails, swelling or soreness of the tongue, cracks in the sides of the mouth, loss of taste, an enlarged spleen, and frequent infections. Iron deficiency has also been associated with recurrent aphthous stomatitis (canker sores) (Akintoye, Dent Clin North Am 2014). Some people with iron-deficiency anemia develop restless legs syndrome (see more about this in Benefits of Correcting Iron Deficiency below). Iron deficiency anemia can also cause irregular heartbeats (arrhythmias), a heart murmur, an enlarged heart, and heart failure (Kettaneh, Appetite 2005; NIH, 2014).

Iron deficiency is most common in menstruating women but also is commonly seen in children and pregnant women. According to the CDC, 9.5% of women 12 - 29 years are deficient, as are 6.7% of children ages 1 to 5. There are higher rates of iron deficiency in Mexican-American children aged 1 to 5 years (11%) and in non-Hispanic black (16%) and Mexican-American women (13%) of childbearing age (12 to 49 years) when compared to other race/ethnic groups. Low iron levels also may result from excessive bleeding, burns, and hemodialysis, as well as stomach and intestinal problems. Drugs that reduce stomach acid may also impair iron absorption (see What to avoid when taking).

During pregnancy, iron deficiency can result in preterm delivery and low-birth-weight babies.

Among children, iron deficiency is most common from ages 6 to 24 months, where it can cause developmental and behavioral problems. If iron deficiency is extremely severe, some of these problems can be irreversible.

Although few men are deficient in iron, 29% are at-risk for iron excess (CDC 2012).

Benefits of Correcting Iron Deficiency
Some evidence suggests that even mild iron deficiency, too mild to cause anemia, may cause fatigue and impair sports performance. Iron supplementation has been shown to reduce unexplained fatigue in women of child-bearing age who are not anemic but have ferritin levels in the lower end of normal range (less than 50 ug/L) (ferritin is an indicator of total iron stored in the body). A 12-week study of 198 such women (ages 18 to 53) found that those who received 80 mg of iron from ferrous sulfate daily from a time-release pill experienced a 47.7% decrease in fatigue, compared to a 28.8% decrease in the placebo group — a significant difference (Vaucher, CMAJ 2012), although there was no significant effect on anxiety or depression. Ferritin levels increased by 11.4 ug/L compared with placebo.

Among blood donors with normal hemoglobin levels, low-dose iron supplementation (37.5 mg of iron as ferrous gluconate daily) reduces the time by more than half for hemoglobin and ferritin levels to recover after donating a unit of blood. A study showed that those receiving iron recovered most of their decrease within about 30 days versus 78 to 158 days for those not receiving iron, depending on whether their ferritin levels were initially high or low. For those getting the iron supplement, ferritin levels returned to normal within 76 days while 67% of those not receiving supplementation had not fully recovered iron stores after 168 days -- when the study ended (Kiss, JAMA 2015). The researchers noted that although the hemoglobin decrease after donation is relatively small (about 10%) and of marginal clinical significance, for frequent donors it is important to be recovered before the next donation; suggesting that the current waiting period of 8 weeks (56 days) in the U.S. may be too short.

Verbal learning and memory have been shown to improve when adolescent girls with iron deficiency (although not anemia) are treated with iron supplementation (Bruner, Lancet 1996).

Unfortunately, among patients with heart failure and iron deficiency, giving high-dose iron (150 mg as iron polysaccharide) twice daily for 16 weeks did not improve peak oxygen uptake nor exercise capacity (6-minute walking distance) and only minimally improved iron levels (a 3% increase). A possible reason for the failure (which was not expected, as iron given intravenously in such patients raises iron by about 70%), was abnormally high blood levels in these people of hepcidin, an iron regulatory hormone that lowers iron levels by reducing iron absorption and trapping iron in while blood cells and liver cells (Lewis, JAMA 2017).

People with low or deficient levels of iron may be more likely to suffer from restless legs syndrome. Guidelines from the American Academy of Neurology advise that taking 65 mg of iron (from 325 mg ferrous sulfate) and 200 mg vitamin C (to help with iron absorption) twice daily may improve symptoms in individuals with restless legs syndrome who have ferritin levels below 75 ng/mL (Winkelman, Neurology 2016). This recommendation is based on a small study that gave a similar treatment (although half the vitamin C: 100 mg twice daily) to older men and women with low-normal blood ferritin levels (15 - 75 ng/mL) for three months. The severity of restless legs symptoms decreased by an average of 10 points on a scale of 0 to 40, while it decreased by just 1 point among those who took a placebo (Wang, Sleep Med 2009). Overall quality of life, however, did not improve in either group. Taking the iron increased blood ferritin levels from an average of 40 ng/mL to 65 ng/mL. Be aware that restless legs syndrome may also occur as a result of hereditary hemochromatosis (a disorder in which too much iron is absorbed from the diet and ferritin blood levels can get too high) and this treatment would not seem appropriate in such a situation (Cotter, Ther Clin Risk Manag 2006).

Other Uses
Iron supplements have shown some promise for reducing the dry cough caused by drugs in the angiotensin-converting enzyme inhibitor family (ACE inhibitors).

A small study of iron in children with ADHD showed improvement in some symptoms comparable to that with stimulant medicines (Konofal,Pediatr Neurol 2008).

A lower risk of suffering PMS (premenstrual syndrome) has been associated with a high intake of iron (over 20 mg per day) from supplements or plant-based foods (as opposed to meats) (Chocano-Bedoya, Am J Epidem 2013). Compared to women with the lowest daily intakes of iron (median of 9.4 mg) from these sources, the risk of PMS was reduced by 29% among those with a median intake of 21.4 mg, and by 36% among those with a median intake of 49.2 mg. Interestingly, the same study found that women consuming higher amounts of potassium from their diet (median intake of 3,717 mg daily) had a higher risk of PMS than those consuming less potassium.

See ConsumerTips for information about the forms of iron in supplements and dosage.

Quality Concerns and What CL Tested For:

In 1997, the U.S. Food and Drug Administration (FDA) reported that several iron-containing supplements had been recalled because of excessive levels of lead. Subsequent testing by ConsumerLab.com similarly found some iron products to be contaminated with lead -- a potentially harmful contaminant. However, tests by ConsumerLab.com since 2011 have found few instances of lead contamination, although some supplements have been discovered to contain less than their claimed amounts of iron. Because no government agency is responsible for routinely testing iron supplements for their contents or quality, ConsumerLab.com independently evaluated iron products to determine whether they contained the iron stated on their labels. Products containing whole herbs and/or 250 mg or more of minerals per daily serving were also tested for contamination with lead, cadmium and arsenic. Iron tablets and caplets that were not chewable or time-release were additionally tested for their ability to break apart ("disintegrate") as needed for absorption. (See Testing Methods and Passing Score.)

What CL Found:

Quality
Our tests found that most iron supplements were well made and contained the iron they listed, so that 13 of the 14 products we selected for testing were Approved for their quality, as were an additional 8 products tested in our voluntary Quality Certification Program.

The one product that we selected for testing but failed to pass was Floradix Iron Tablets (10 mg). It contained its listed amount of iron but the tablets failed to fully break apart in disintegration testing within the required 30 minutes — they needed 60 minutes. A concern with slower disintegration is that the ingredients may not be fully available for absorption in the gut. All other regular tablets and caplets fully disintegrated in less than 30 minutes or less.

Cost
We also compared products on the cost to obtain from each an equivalent amount (25 mg) of iron (which is more than the recommended daily allowance but about the mid-point in dosage among iron supplements). The cost to obtain 25 mg of iron ranged from just $0.01 to over $2.00 -- a 200-fold difference. The least expensive way to get iron was from high-dose products (i.e., those with 65 mg of iron per unit) made of ferrous sulfate -- Member's Mark Iron and Nature Made Iron, each of which cost only 3 cents per tablet. The last column in the Results table below identifies the lowest cost products for each type of iron.

Which iron supplement is best?
The iron supplement you select should provide:

the right dose of iron for the therapeutic use for which you will be taking it
the right form of iron to allow good absorption but be least likely to cause gastrointestinal side effects such as constipation
the best quality, i.e., be well made, properly labeled, and Approved in our tests, and
the best value (i.e., the least cost for the form of iron you've chosen)

Considering these factors, we have made the following CL Top Picks (below) among iron supplements Approved in our tests.

Top Picks
CL's overall Top Pick among iron supplements is NOW Iron which provides 18 mg (the recommended daily allowance for women ages 19 — 50) of iron per vegetarian capsule in the form of ferrous bisglycinate for 6 cents. This form of iron has been shown to be absorbed two to four times better than ferrous sulfate when taken with food, and may cause less gastrointestinal discomfort than ferrous sulfate, ferrous fumarate, and ferrous gluconate. In general, taking iron with food will help reduce gastrointestinal discomfort that iron may cause.

However, if you have no trouble tolerating ferrous sulfate taken with just water, you can spend less and take one of the ferrous sulfate supplements such as Member's Mark Iron and Nature Made Iron, each providing 65 mg of iron per 3 cent tablet. If you want a lower dose, use Fergon, which contains 27 mg of iron in the gluconate form for 10 cents. In fact, to maximize absorption of iron, regardless of form, it is best to take iron with just water. But if you need to take iron with food or within an hour after eating, the bisglycinate form is better absorbed.

Be aware that the amount of iron in NOW Iron (18 mg) is the daily requirement for women who have not gone through menopause. It's not enough, however, to correct an iron deficiency and, at the same time, it's more than most children, adolescents, and men need on a daily basis.

If you need more iron and are unable to take it with water, our Top Picks are other products with iron bisglycinate -- Nature's Bounty Gentle Iron (8 cents per capsule providing 28 mg of iron) or Solgar Gentle Iron 25 mg (9 cents per vegetable capsule) which is also vegetarian and Kosher.

Several timed-release or slow release products were Approved (Ferro-Sequels, Jamieson, and Well at Walgreens). While these are said to reduce gastric irritation from iron, there is concern that, due to the slower release, less iron may be available in the small intestine, which is where iron gets absorbed. Consequently, none of these is among our Top Picks.

Several products include modest amounts of vitamin C, ostensibly to boost iron absorption, but it's unlikely that this helps much, so is not worth paying more for the vitamin C.

Test Results by Product:

Listed alphabetically below are the test results for 22 iron products. ConsumerLab.com selected 14 of these products. Eight other products (indicated with a CL flask) were tested at the request of their manufacturers/distributors through ConsumerLab.com's voluntary Quality Certification Program, and are included for having passed testing.

Shown for each product is the labeled amount of elemental iron per unit, the daily number of servings recommended on the label, the expected dosage of iron per day based on that recommendation, and the form of iron listed on the label. The calculated cost to obtain 25 mg of iron is provided in the last column along with the price per serving, price paid, and additional key ingredients and special dietary designations.

The full list of ingredients is available for each product by clicking on the word "Ingredients" in the first column. All the "Approved" products met their label claims for iron, met FDA labeling requirements, and, non-chewable and non-time-release tablets and caplets were shown to break apart properly. In addition, Approved products containing whole herbs and/or 250 mg or more of minerals per daily serving did not exceed contamination limits for lead, cadmium or arsenic.

Many of the products are designed for treating iron deficiency and, therefore, exceed the Recommended Dietary Allowance (RDA) as well as the upper level (UL) of tolerable intake for iron. Those exceeding the UL are footnoted alongside their Approval status. Under a physician's supervision it's acceptable to exceed these limits, because the potential consequences of untreated iron deficiency may be more severe than the potential.

Show the results table

RESULTS OF CONSUMERLAB.COM TESTING OF IRON SUPPLEMENTS Click on beneath a product name to find a vendor that sells it. To find retailers that sell some of the listed products click here.
Product Name, Amount Listed of Iron per Unit, Serving Size, and Suggested Daily Serving on Label Click on "Ingredients" for Full Listing	Claimed Amount Iron Per Labeled Daily Serving (Form of Iron)	--TEST RESULTS-- (See How Products Were Evaluated)				Cost For Daily Suggested Serving On Label [Cost Per 25 mg Iron] Other Notable Features² Price Paid
		OVERALL RESULTS: APPROVED or NOT APPROVED	Contained Labeled Amount of Iron	Did Not Exceed Contamination Limit for Lead, Cadmium and Arsenic¹	Disintegrated Properly (NA = Not Applicable)
Country Life® Easy Iron (25 mg per vegan capsule; 1 vegan capsule, once daily) Mfd. by Country Life, LLC Ingredients	25 mg (Ferrochel® ferrous bisglycinate) Large vegan capsule	OVERALL RESULTS: APPROVED or NOT APPROVED	APPROVED		NA	NA	$0.10 [$0.10] Kosher, suitable for vegans, no wheat and yeast, gluten free $9.35/90 vegan capsules
Feosol® Bifera® HIP & PIC Iron (28 mg per caplet; 1 caplet, once daily) Dist. by Meda Consumer Healthcare Inc. Ingredients	28 mg (PIC - polysaccharide iron complex, HIP - heme iron polypeptide as Proferrin®) Medium/large caplet	APPROVED		NA		$0.49 [$0.43] Lowest cost Approved iron PIC/HIP $14.57/30 caplets
Fergon® (27 mg per tablet; 1 tablet; once daily) Dist. by Strides Pharma Inc. Ingredients	27 mg (ferrous gluconate) Medium circular tablet	APPROVED		NA		$0.10 [$0.10] *Lowest cost Approved iron gluconate* (moderate dose)** $10.37/100 tablets
Ferro-Sequels® (65 mg per caplet; 1 caplet, once daily) Dist. by International Vitamin Corporation Ingredients	65 mg³ (ferrous fumarate) Medium/large caplet	APPROVED		NA	NA	$0.26 [$0.10] *Lowest cost Approved iron fumarate* (moderate dose)** Vitamin C (25 mg) Timed Release Gluten free $25.99/100 caplets
Floradix® Iron Tablets (10 mg per tablet; 1 tablet, twice daily) Dist. by Flora Inc. Ingredients	20 mg (ferrous gluconate) Medium circular tablet	NOT APPROVED		NA	Did not fully disintegrate in 30 minutes (Required 60 minutes)	$0.52 [$0.64] Vitamin C (18 mg), thiamine (1.26 mg), riboflavin (1.44 mg), niacin (9 mg), vitamin B6 (1.35 mg), folic acid (360 mcg), vitamin B12 (1.7 mcg), proprietary blend (dried mixed extract of spinach leaf, carrot root, fennel seed, centaury, rosehip extract) (110 mg) Kosher $20.63/80 tablets
Garden of Life® mykind Organic Plant Iron & Organic Herbs (10 mg per 10 mL; 10 mL, once daily) Dist. by Garden of Life LLC Ingredients	10 mg (from organic food blend) Liquid from bottle	APPROVED			NA	$0.90 [$2.26] Vitamin C (15 mg), vitamin B6 (2 mg), vitamin B12 (100 mcg), certified organic food blend (curry Murraya koenigii, strawberry, tart cherry, beet, broccoli, carrot, spinach, blackberry, tomato, amaranth, buckwheat, millet, quinoa, adzuki bean, chia seed, flax seed, garbanzo bean, lentil, pumpkin seed, sesame seed, sunflower seed, blueberry, raspberry, cabbage, brussels sprout, garlic, onion, ginger, cauliflower, parsley, green bell pepper, celery, cucumber, kale, asparagus) (353 mg), certified organic ayurvedic herbal blend (amla berry, ashwagandha) (128 mg); USDA Organic Seal; Non GMO Project Verified Seal; Certified Vegan Vegan.com Seal Kosher, suitable for vegans, non-GMO, organic, gluten free $21.69/8 fl. oz. [240 mL] bottle (approx. 24 servings)
GNC Gentlesorb Iron™ (18 mg per vegetarian capsule; 1 vegetarian capsule, once daily) Dist. by General Nutrition Corporation Ingredients	18 mg (hydrolyzed protein chelate) Large vegetarian capsule	APPROVED		NA	NA	$0.11 [$0.15] Lowest cost Approved iron protein chelate No wheat, gluten free $9.99/90 vegetarian capsules
Jamieson™ Iron 50 mg (50 mg per caplet; 1 caplet, once daily) Dist. by Jamieson Laboratories Ingredients	50 mg³ (ferrous gluconate) Large caplet	APPROVED		NA	NA	$0.16 [$0.08] Lowest cost Approved iron gluconate (very high dose) Timed Release No gluten $9.60/60 caplets
Life Extension® Iron Protein Plus (15 mg per capsule; 1 capsule, once daily) Dist. by Quality Supplements and Vitamins, Inc. Ingredients	15 mg (IronAid® iron protein succinylate) Large capsule	APPROVED		NA	NA	$0.20 [$0.33] Lowest cost Approved iron protein succinylate $19.50/100 capsules
Member's Mark® [Sam's Club] Iron (65 mg per tablet; 1 tablet, once daily) Dist. by Sam's West, Inc. Ingredients	65 mg³ (ferrous sulfate) Medium circular tablet	APPROVED		NA		$0.03 [$0.01] *Overall lowest cost Approved iron (sulfate form)* No wheat and yeast, gluten free $8.98/300 tablets
Nature Made® Iron (65 mg per tablet; 1 tablet, once daily) Dist. by Nature Made Nutritional Products Ingredients	65 mg³ (ferrous sulfate) Medium circular tablet	APPROVED		NA		$0.03 [$0.01] *Overall lowest cost Approved iron (sulfate form)* Calcium (18 mg); USP Dietary Supplement Verified Seal Gluten free, no yeast $8.18/260 tablets
Nature's Bounty® Gentle Iron® (28 mg per capsule; 1 capsule, once daily) Mfd. by Nature's Bounty, Inc. Ingredients	28 mg (ferrous bis-glycinate) Large capsule	APPROVED		NA	NA	$0.08 [$0.07] Lowest cost Approved iron bisglycinate Vitamin C (60 mg), folic acid (400 mcg), vitamin B12 (8 mcg) No wheat, gluten and yeast $7.49/90 capsules
NovaFerrum® Pediatric Drops Liquid Iron - Raspberry Grape Flavor (15 mg per 1 dropperful [1 mL]; 1 dropperful, once daily) Dist. by Gensavis® Pharmaceuticals LLC Ingredients	15 mg (polysaccharide iron complex) Liquid from bottle	APPROVED		NA	NA	$0.22 [$0.36] Lowest cost Approved iron polysaccharide complex Kosher, suitable for vegans $25.99/4 fl. oz. [120 mL] bottle (approx. 120 servings)
NOW® Iron (18 mg per veg capsule; 1 veg capsule, once daily) Dist. by Now Foods Ingredients	18 mg (Ferrochel® ferrous bisglycinate) Large veg capsule	APPROVED		NA	NA	$0.06 [$0.08] Not manufactured with wheat and gluten $6.79/120 veg capsules
Rexall® [Dollar General] Iron 65 mg (65 mg per tablet; 1 tablet, once daily) Dist. by Dolgencorp, LLC Ingredients	65 mg³ (ferrous sulfate) Medium tablet	APPROVED		NA		$0.05 [$0.02] No wheat, gluten and yeast $4.50/100 tablets
Solaray® BioCitrate™ Iron (25 mg per vegetarian capsule; 1 vegetarian capsule, once daily) Mfd. by Nutraceutical Corp. Ingredients	25 mg (ferrous citrate) Large vegetarian capsule	APPROVED			NA	$0.11 [$0.11] Lowest cost Approved iron citrate $6.62/60 vegetarian capsules
Solgar® Gentle Iron® 25 mg (25 mg per vegetable capsule; 1 vegetable capsule, once daily) Mfd. by Solgar, Inc. Ingredients	25 mg (ferrous bisglycinate) Large vegetable capsule	APPROVED		NA	NA	$0.09 [$0.09] Lowest cost Approved iron bisglycinate chelate Kosher, free of wheat and yeast, gluten free $15.68/180 vegetable capsules
Spring Valley™ [Walmart] Iron (65 mg per tablet; 1 tablet, once daily) Dist. by Wal-Mart Stores, Inc. Ingredients	65 mg³ (ferrous sulfate) Medium circular tablet	APPROVED		NA		$0.07 [$0.03] $14.16/200 tablets (2 pack of 100 tablets bottles)
VegLife® Vegan Iron Chewable - Berry Flavor (18 mg per chewable tablet; 1 chewable tablet, once daily) Mfd. by Nutraceutical Corp. Ingredients	18 mg (ferrous glycinate) Medium/large circular chewable tablet	APPROVED			NA	$0.11 [$0.15] Lowest cost Approved iron glycinate Vitamin C (60 mg), folate (100 mcg), vitamin B12 (20 mcg) Suitable for vegans $6.53/60 chewable tablet
Vitamin Friends® Iron (5 mg per gummy; 1 gummy, once daily) Dist. by Vitamin Friends, LLC Ingredients	15 mg (ferrous fumarate) Large character gummy	APPROVED		NA	NA	$0.24 [$1.18] Bata carotene (37 mcg), vitamin C (15 mg), niacin (2 mg), vitamin B6 (0.4 mg), folic acid (50 mcg), vitamin B12 (0.34 mcg), pantothenic acid (1 mg), zinc (0.17 mg); Certified Organic Oregon Tilth Seal; Certified Vegan Vegan.org Seal Kosher, suitable for vegans, organic $28.35/120 gummies (2 pack of 60 gummies bottles)
Well at Walgreens Slow Release Iron (45 mg per tablet; 1 tablet, once daily) Dist. by Walgreen Co. Ingredients	45 mg⁴ (ferrous sulfate) Medium circular tablet	APPROVED		NA	NA	$0.17 [$0.09] *Lowest cost Approved iron as slow release* (sulfate form)** Slow release $19.99/120 tablets
Wellesse® Liquid Iron - Berry Flavored (18 mg per tbsp. [15 mL]; 1 tablespoon, once daily) Dist. by Nature's Way Brands, LLC Ingredients	18 mg (ferrous glycinate) Liquid from bottle	APPROVED		NA	NA	$0.25 [$0.35] $8.05/16 fl. oz. [480 mL] bottle (approx. 32 servings)
Tested through CL's Quality Certification Program prior to, or after initial posting of this Product Review. - Canadian product. 1 Products were only tested for lead, cadmium and arsenic if they contain any whole herbs and/or 250 mg or more minerals daily. 2 Not tested but claimed on label. 3 Over the tolerable upper intake level (UL) for all individuals for iron. The UL for ages 14 and up is 45 mg per day. 4 At tolerable upper intake level (UL) for ages 14 and up.
Unless otherwise noted, information about the products listed above is based on the samples purchased by ConsumerLab.com (CL) for this Product Review. Manufacturers may change ingredients and label information at any time, so be sure to check labels carefully when evaluating the products you use or buy. If a product's ingredients differ from what is listed above, it may not necessarily be of the same quality as what was tested. The information contained in this report is based on the compilation and review of information from product labeling and analytic testing. CL applies what it believes to be the most appropriate testing methods and standards. The information in this report does not reflect the opinion or recommendation of CL, its officers or employees. CL cannot assure the accuracy of information.
Copyright ConsumerLab.com, LLC, 2017. All rights reserved. Not to be reproduced, excerpted, or cited in any fashion without the express written permission of ConsumerLab.com LLC.

ConsumerTips for Buying and Using:

How Much to Take?
To Treat Iron Deficiency and Anemia
In general, a typical adult dosage for correcting iron-deficiency anemia is 100 to 200 mg daily, divided into two or three separate doses. However, the recommended dose depends on the severity of the anemia and weight of the individual. Your physician should determine the dose. Approximately two months' time is usually required to restore hemoglobin levels. Many more months of iron supplementation may be required to fully build up iron stores. A dose of 80 mg of iron from ferrous sulfate given as a time-release pill daily for 12 weeks has been used to treat unexplained fatigue in women who are not anemic but have low ferritin levels (Vaucher, CMAJ 2012). (Note: A timed-release pill Approved in this Review is Ferro-Sequels).

To Prevent Anemia
The daily recommended intake of iron for healthy individuals depends on your gender and life stage. Most people are able to meet the requirement from their diet, from foods such as meat, poultry, and fish, as well as from dried fruits, grains, and green leafy vegetables. The average diet provides about 10 to 20 mg of iron per day. Bear in mind that iron from plant sources is absorbed half as well as that from animal sources. Consequently, vegetarians who exclude all animal products from their diets may need almost twice as much dietary iron each day as non-vegetarians. (Vegetarians should consider consuming plant sources of iron along with a good source of vitamin C, such as citrus fruits, to improve the absorption of iron from these foods).

The RDA (Recommended Daily Allowance) for iron is 7 mg for children ages 1 to 3 and 10 mg for children ages 4 to 8. It then decreases to 8 mg for children ages 9 to 13. For males ages 14 to 18, the RDA is 11 mg; 19 and older, it decreases to 8 mg. For females, ages 14 to 18, the RDA is 15 mg; 19 to 50, it's 18 mg, decreasing to 8 mg ages 51 and older.

Because of fetal needs, the RDA for pregnant women is 27 mg. For breast-feeding women younger than age 18, the RDA is 10 mg; ages 19 and older, it's 9 mg. Also, postmenopausal women taking hormone replacement therapy should consume more iron because the therapy can cause periodic uterine bleeding. Oral contraceptives may reduce menstrual blood loss, so women taking them may need less daily iron.

The FDA requires that dietary supplements state on their labels the % Daily Value for certain vitamins and minerals. However, this is based on an average and may not be appropriate for you, so use the RDAs above. When reading labels, remember that 1,000 mcg (micrograms) equals 1 mg (milligram) and that 1,000 mg equals 1 gram.

For Other Uses (see What It Does section for clinical information)
To improve cognitive function in non-anemic, iron deficient adolescent girls, 130 mg of iron (as 650 mg of ferrous sulfate) given twice daily has been used (Bruner, Lancet 1996).

To speed the recovery of hemoglobin and ferritin levels after blood donation, 37.5 mg of iron (as ferrous gluconate) has been used (Kiss, JAMA 2015).

To inhibit dry cough associated with ACE inhibitors, 51.2 mg of iron daily (as 256 mg of ferrous sulfate) has been used (Lee, Hypertension 2001).

To treat ADHD in children (aged 5 to 8) who are not anemic, 80 mg of iron daily (given as ferrous sulfate) has been used (Konafal, Pediatr Neurol 2008).

Upper limit -- Don't take too much!
High daily amounts of iron can cause gastrointestinal distress, especially when iron supplements are consumed on an empty stomach, and there are additional risks with long-term use of high-dose iron (see Concerns and Cautions). The Upper Tolerable Intake Level (UL) is 40 mg for children younger than age 13 and 45 mg for everyone else. However, these limits may be too high for people with hereditary hemochromatosis who are at unique risk for accumulating harmful levels of iron. Be aware that labels are unlikely to provide information indicating whether the ingredients exceed tolerable intake levels -- the FDA doesn't require that information.

Forms of Iron and Avoiding Stomach Upset:

Several different forms of iron are used in supplements. The actual amount of usable "elemental" iron per milligram of iron compound varies depending on the form. For example, 20% of ferrous sulfate is iron and only 12% of ferrous gluconate is iron. Put another way, to get 50 mg of iron, you could take about 250 mg of ferrous sulfate or about 417 mg of ferrous gluconate. Fortunately, the consumer doesn't need to do the calculations -- the manufacturer does this. The usable amount or iron (elemental iron) is what appears in the Supplement Facts panel on the label. Generally, the least expensive forms of iron are ferrous sulfate, ferrous fumarate, and ferrous gluconate. If you have trouble tolerating these forms of iron due to gastrointestinal discomfort, consider ferrous bisglycinate, ferrous glycinate, or iron amino acid chelates. (One study showed ferrous bisglycinate (also known as iron bis-glycinate or Ferrochel) to be absorbed two to four times better than ferrous sulfate when given with food (Layrisse, J Nutr 2000), although it was not absorbed better than ferrous ascorbate when given only with water (Olivares, Arch Latinoam Nutr 2001). Timed-release iron supplements may also reduce gastrointestinal discomfort, but there is some concern that they reduce iron absorption.

Some supplements contain heme-iron polypeptide or HIP, which appears to be better absorbed than iron salts, such as ferrous sulfate. This was shown in a study in which both HIP and ferrous sulfate were taken with breakfast although the food ingested may have interfered with ferrous sulfate absorption. Preliminary evidence suggests that HIP may also be better tolerated than ferrous sulfate (Seligman, Nutrition Research 2000). A branded version of HIP is Proferrin which is found in Feosol Bifera in this Review, which also includes another iron ingredient, polysaccharide-iron complex or PIC. The absorption of PIC is about the same as ferrous sulfate, but it is apparently tasteless and odorless and may cause less gastric irritation.

A study in infants and young children with nutritional iron-deficiency anemia comparing equal, low-dose amounts of iron from ferrous sulfate and PIC (as NovaFerrum) found ferrous sulfate to increase hemoglobin levels slightly better PIC and completely resolve anemia in more patients compared to PIC (29% vs 6%). Researchers had expected the opposite. There were also fewer reports of diarrhea in these children with ferrous sulfate than with PIC (35% vs 58%), although somewhat more reports of vomiting with ferrous sulfate (58% vs 45%). The doses were given as liquid drops at bedtime (Powers, JAMA 2017).

Another form, carbonyl iron, may present a reduced risk of harm in an accidental overdose. Carbonyl iron, consequently, is the ingredient many children's supplements contain and may be preferred by parents of small children. However, carbonyl iron requires adequate stomach acid for absorption. Therefore, it should be taken with food and not used with medications that reduce stomach acid. Injectable iron also is available under the supervision of a health professional. Taking iron supplements with food may also help avoid gastric upset. Though combining the supplement with food may decrease iron absorption, taking it with a vitamin C-rich food may offset that effect because vitamin C boosts iron absorption. In fact, some iron supplements contain vitamin C as an added ingredient to aid absorption (although the amount added may not be sufficient to make a difference). Constipation can be a side-effect of oral iron supplementation, especially when taken in higher doses (Fei, Clinical Correlations 2015). Ferrous and ferrous salts (ferrous sulfate, ferrous gluconate, ferrous fumarate and ferrous glycinate sulfate) have been found to have similar incidence of constipation when compared in a clinical study (Hallberg, Acta Med Scand Suppl 1966). However, heme iron polypeptides, carbonyl iron, iron amino-acid chelates, and polysaccharide-iron complexes (PIC) may have a lower incidence of gastrointestinal side-effects than ferrous or ferric salts (NIH Iron Fact Sheet 2016). Iron protein succinylate has also been found to have a slightly lower incidence of constipation and less gastric irritation. Long term, it may result in somewhat greater improvement in iron measurements in the body than ferrous sulfate (Liquori, Int J Pharmacol Ther Toxicol 1993). Iron protein succinylate is the form found in Life Extension Iron Protein Plus in this Review. Rarely, severe constipation due to iron supplementation may interfere with the intestine's ability to properly contract (to move waste through the body), leading to bowel obstruction, as was reported in a 55-year-old women one week after she began taking iron pills to treat iron deficiency anemia. Increasing dietary fiber intake and/or using stool softeners can help to prevent constipation when taking iron supplements (Parvataneni, Cureus 2020).

What to avoid when taking
Remember that many antacids can decrease iron absorption, and the dose and duration of use of certain antacids may increase the risk of iron deficiency. For example, taking 20 mg or more daily of a proton pump inhibitor (PPI) drug such as omeprazole (Prilosec), esomeprazole (Nexium) or lansoprazole (Prevacid) for more than one year was associated with 3.6 times the risk of iron deficiency, while "intermittent use" of PPIs during the same time period was associated with a 50% increased risk of deficiency, compared to no use of PPIs, according to an analysis of over 50,000 people in the United Kingdom (Tran-Duy, J Intern Med 2018). Certain foods and beverages, including soy protein, coffee, eggs, whole-grain cereals and breads, and spinach, can also reduce iron absorption, as can tea (Gillooly, Br J Nutr 1983; Hurrell, Am J Clin Nutr 2010). A small study in England showed that consuming about one cup of brewed black tea with an iron containing meal reduced the amount of iron normally absorbed by 37%. However, consuming tea one hour after the meal had no effect on iron absorption (Fuzi, Am J Clin Nutr 2017).

Iron absorption also can be reduced by high doses of other minerals, such as zinc, manganese, magnesium or copper. When consuming one of these foods or high-dose mineral supplements, wait 2 hours to take your iron supplement. Calcium is particularly prone to inhibiting iron absorption: A study showed that taking a calcium supplement (300 mg or 600 mg of calcium) at the same time as taking an iron supplement reduced iron absorption by as much as 62%. Calcium similarly reduced iron absorption from food (Cook, Am J Clin Nutr 1991). The problem can be avoided by taking a calcium supplement at least 2 hours apart from taking an iron supplement or consuming an iron-containing meal. This interaction is not likely to be a significant problem with lower doses of calcium (under 200 mg) or for people who are not prone to iron deficiency. Be aware that some multivitamins for women (who are most at-risk for iron deficiency if they have not yet gone through menopause) contain 500 mg or more of calcium.

Concerns and Cautions:

Although iron supplements are safe and potentially helpful when taken in appropriate amounts, excessive iron intake can be harmful:

The most common immediate side effect of iron supplements is gastrointestinal distress including constipation, nausea, and diarrhea. Nausea and stomach upset often occurs when a high-dose iron supplement is taken on an empty stomach. This risk of nausea and gastrointestinal upset may be reduced with certain forms of iron and/or by taking iron with food. Certain forms of iron are also less likely to cause constipation; increasing dietary fiber intake and using stool softeners may also help (see Forms of Iron and Avoiding Stomach Upset).
Occasionally, use of iron pills can damage the protective lining of the stomach, leading to stomach erosions and ulcers, and gastrointestinal bleeding (known as iron-pill induced gastropathy), which can result in a worsening of anemia. This may be more likely to occur in older adults. The liquid form of oral iron (as well as intravenous iron) is less likely to damage the lining of the stomach. Reported cases have included two men (ages 72 and 81) and a woman (age 90) in Florida, all of whom were taking tablets providing 325 mg of iron (as ferrous sulfate) one to two times daily to treat iron-deficiency anemia. Their symptoms resolved after they were switched to intravenous iron for their anemia and their stomach damage was treated with medication (Comba, American College of Gastroenterology Annual Scientific Meeting 2019). Gastritis and a non-bleeding stomach ulcer were also reported in a 46-year-old woman taking iron pills for iron-deficiency anemia (Sunkara, Gastroenterology Res 2017).
Iron at greatly excessive doses taken continually can result in toxicity, causing cirrhosis, coronary heart disease, congestive heart failure, and other problems.
Other problems can occur with prolonged excessive intake of iron. For example, while pregnant women are generally encouraged to take iron supplements, supplementation beyond the recommended amount may increase complications of pregnancy. Also, one study found that non-iron-deficient, breast-fed infants do not benefit from iron supplements. These infants might even experience an overall decrease in health if given iron supplementation.
Observational studies have found associations between mildly excessive levels of stored iron in the body and heart disease, cancer and type 2 diabetes. Higher levels of stored iron have also been associated with a modestly higher risk of stroke, particularly cardioembolic stroke (i.e., stroke due to clot or plaque debris coming from the heart), possibly due to an excess of iron triggering clot formation (Gill, Stroke 2018). This does not prove that excessive iron intake causes those diseases, but it does suggest a connection. On this basis, it appears prudent to suggest that people should generally not take iron supplements unless blood tests have shown them to be iron deficient. Note that non-vegetarian adult men and post-menopausal women are unlikely to lack adequate iron. In fact, according to the CDC, 29% of men are at-risk for iron excess.
A study of postmenopausal women found the use of iron supplements to be associated with a 3.9% increased risk of death over a 22-year period. The risk increased as the dosage increased (particularly at very high dosages of 50 mg to several hundred milligrams per day) (Mursu, Ach Int Med 2011). However, the study grouped dosages of under 50 mg together, making it hard to determine the risk of lower dosages of iron, such as those in many multivitamins.
Use of iron supplements before or during chemotherapy for breast cancer has been associated with a with a 91% higher risk of cancer recurrence (Ambrosone, J Clin Oncol 2020).
Vitamin C increases iron absorption, and, consequently, people who take very high doses of vitamin C (a gram or more daily) are at increased risk of iron toxicity. Toxicity is of particular concern for individuals with hemochromatosis, a genetic condition affecting 1 out of 200 to 500 people. With hemochromatosis, excessive amounts of iron build up in the body's tissues and organs.
High doses of ferrous iron (but not ferric iron) or other minerals (calcium, magnesium, and zinc) from supplements may decrease the absorption of carotenoids, such as beta-carotene, lycopene and astaxanthin, from foods and/or supplements. This is likely due to a reaction between carotenoids and the divalent ions of these minerals, making the carotenoids less bioavailable (Corte-Real, Food Chem 2016; Biehler, J Nutr 2011). It is best to take carotenoid supplements at a different time of day than a supplement or meal containing large amounts of a mineral.

Iron supplements also may reduce the absorption of certain drugs such as levodopa, levothyroxine, penicillamine, quinolone antibiotics, tetracycline antibiotics, and, possibly, ACE-inhibitors. Conversely, some of these drugs may interfere with iron absorption. It is best to take these medications at a different time of day than when taking an iron supplement. This caution may also apply to the anti-seizure medication carbamazepine, as suggested by a study that found that iron supplementation may lower carbamazepine concentrations by as much as approximately 30%, possibly by reducing bioavailability (Ahn, Epilepsy Res 2019).

Remember, iron supplements are a leading cause of poisoning in children younger than age 6. Just a few adult tablets can cause serious poisoning, so keep iron products away from children's reach. To help reduce the number of such poisonings, supplements containing 30 mg or more of iron (other than carbonyl iron) can only be sold in child-resistant bottles or in single-dose packaging.

Additional information about iron is found in the Natural Products Encyclopedia on this website. An excellent Fact Sheet about iron supplementation is available from the government Office of Dietary Supplements.

Information on this site is provided for informational purposes only. It is not an endorsement of any product nor is it meant to substitute for the advice provided by physicians or other healthcare professionals. The information contained herein should not be used for diagnosing or treating a health problem or disease. Consumers should inform their healthcare providers of the dietary supplements they take.

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