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Last Updated: 09/21/2021 |


What is iron? 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 iron 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 of iron is best? Iron comes in many chemical forms and formulations, including pills, liquids, and gummies. 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).

Best iron supplements: 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 iron to take, safety and side effects: 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).

Iron-deficiency anemia is one of the most common deficiencies in people with Crohn's disease and other forms of inflammatory disease (IBD). This may be treated with iron supplements, although in some cases, intravenous or prescription iron may be recommended (Crohn's and Colitis Foundation 2017). A particular form of iron known as ferric maltol (Accrufer, Feraccru) that is only available by prescription has been shown to be tolerable and effective in treating iron-deficiency anemia in people with Crohn's or other inflammatory bowel disease who were unable to tolerate other forms of iron, such as ferrous gluconate, ferrous succinate, and ferrous sulfate (Weisshof, Curr Opin Clin Nutr Metab Care 2015).

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 (Trotti, Cochrane Database Syst Rev 2019). 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. [Note: The rationale for taking vitamin C with iron has been that vitamin C increases iron absorption, but any clinical effect may be insignificant. See ConsumerTips™ for more details.]

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) (Lee, Hypertension 2001).

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.

Iron deficiency has been associated with an increased risk of fibromyalgia (widespread muscle pain and fatigue) in women. A study in Taiwan found that women (ages 18 and older, average age 50) with iron deficiency anemia had a 22% increased risk of fibromyalgia compared to women without iron deficiency anemia, but there was no increased risk for men. When people with iron deficiency anemia were receiving iron supplementation, their risk of fibromyalgia was 21% lower than those who received no iron therapy. While this does not prove that iron deficiency causes fibromyalgia in women or that iron supplementation treats fibromyalgia, the researchers recommended that all people with fibromyalgia have their blood levels of iron checked, and corrected with supplementation if needed (Yao, Sci Rep 2021).

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

Quality Concerns and Tests Performed:

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 similarly found some iron products to be contaminated with lead -- a potentially harmful contaminant. However, tests by 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, 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:

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. 

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. selected 14 of these products. Eight other products (indicated with a CL flask) were tested at the request of their manufacturers/distributors through'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 Tolerable Upper Intake 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
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)

(See How Products Were Evaluated)
Cost For Daily Suggested Serving On Label

[Cost Per 25 mg Iron]

Other Notable Features2

Price Paid

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
25 mg

(Ferrochel® ferrous bisglycinate)  

Large vegan capsule


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.
28 mg

(PIC - polysaccharide iron complex, HIP - heme iron polypeptide as Proferrin®)  

Medium/large caplet

Lowest cost Approved iron PIC/HIP

$14.57/30 caplets
Fergon® (27 mg per tablet; 1 tablet; once daily)

Dist. by Strides Pharma Inc.
27 mg

(ferrous gluconate)

Medium circular tablet

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
65 mg3

(ferrous fumarate)

Medium/large caplet

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.
20 mg

(ferrous gluconate)

Medium circular tablet
NOT APPROVED NA Did not fully disintegrate in 30 minutes
(Required 60 minutes)


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)


$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
10 mg

(from organic food blend)

Liquid from bottle


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 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
18 mg

(hydrolyzed protein chelate)

Large vegetarian capsule

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
50 mg3

(ferrous gluconate)

Large caplet

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.
15 mg

(IronAid® iron protein succinylate)  

Large capsule

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.
65 mg3

(ferrous sulfate)

Medium circular tablet

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
65 mg3

(ferrous sulfate)

Medium circular tablet

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.
28 mg

(ferrous bis-glycinate)

Large capsule

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
15 mg

(polysaccharide iron complex)

Liquid from bottle

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
18 mg

(Ferrochel® ferrous bisglycinate)  

Large veg capsule


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
65 mg3

(ferrous sulfate)

Medium tablet


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.
25 mg

(ferrous citrate)

Large vegetarian capsule

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.
25 mg

(ferrous bisglycinate)

Large vegetable capsule

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.
65 mg3

(ferrous sulfate)

Medium circular tablet


$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.
18 mg

(ferrous glycinate)

Medium/large circular chewable tablet

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
15 mg

(ferrous fumarate)

Large character gummy


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 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.
45 mg4

(ferrous sulfate)

Medium circular tablet

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
18 mg

(ferrous glycinate)

Liquid from bottle


$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 (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, LLC, 2017. All rights reserved. Not to be reproduced, excerpted, or cited in any fashion without the express written permission of LLC.


How Much to Take?
To Treat Iron Deficiency and Anemia
Traditionally, a typical recommended adult dosage for correcting iron-deficiency anemia has been 100 to 200 mg daily, divided into two or three separate doses, with the specific recommended dose depending on the severity of the anemia and weight of the individual. However, in September 2021, the British Society of Gastroenterology revised its guidelines, recommending only 50 to 100 mg of iron taken once daily on an empty stomach to correct iron deficiency. This change was based on clinical evidence showing that a single 60-mg dose of iron increased levels of hepcidin, a protein that blocks the absorption of iron from subsequent doses. Consequently, absorption of iron from a single 60-mg daily dose was found to be similar to two 60-mg doses taken the same day. For people with significant gastrointestinal disturbance to oral iron replacement therapy, the British Society of Gastroenterology recommends switching to prescription-only ferric maltol (Accrufer), following alternate day iron therapy, or receiving parenteral (i.e., injectable) iron. It does not recommend switching to a different iron salt form (e.g., from ferrous sulfate to ferrous gluconate or fumarate), as research does not appear to support this practice (Snook, Gut 2021). About 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).

Some experts recommended taking iron along with vitamin C to boost iron absorption. This recommendation stemmed from preliminary research showing that vitamin C can boost iron absorption from a single meal. However, other research found that iron absorption from a complete diet (i.e., several meals over several days) was not increased by vitamin C (Cook, Am J Clin Nutr 2001), and a study in China suggested that vitamin C may not help when taking iron supplements. The study in China among 440 people (average age 38) with iron deficiency anemia found that those taking 100 mg of iron (as ferrous succinate) three times daily after a meal increased levels of hemoglobin (an iron-containing protein in the blood that carries oxygen and is low in people with iron deficiency) at two-week follow-up by about the same amount as those taking each dose of iron along with 200 mg of vitamin C. Also, at eight-weeks follow-up, blood levels of ferritin (a storage form of iron in the blood), as well as iron levels in the blood, increased by about the same amount whether or not iron had been taken with vitamin C (Li, JAMA Netw Open 2020). Based on this evidence, the British Society of Gastroenterology does not recommend taking vitamin C along with iron (Snook, Gut 2021).

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 Tolerable Upper 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. [Ferric maltol also seems to be better tolerated, although this form is available only by prescription.] 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).

Preliminary research has shown that taking lactoferrin (a protein in milk) with iron may help prevent sports anemia (a form of iron-deficiency anemia) in athletes better than taking iron-only supplements. One study in Japan among female long-distance runners found that taking tablets providing 1.8 grams of lactoferrin plus 6 mg of iron (as ferric pyrophosphate) daily during 8 weeks of training prevented a significant decline in blood levels of iron compared to baseline, while taking iron-only supplements did not (Koikawa, Biosci Biotechnol Biochem 2008).

Research has also shown that lactoferrin may help treat iron-deficiency anemia in women and children. A study conducted in Egypt among pregnant women with iron-deficiency anemia found that taking 100-mg lactoferrin oral sachets (MamyVital, Dulex Lab, Cairo, Egypt) twice daily for 4 weeks increased blood levels of iron by 37% compared to iron supplements alone (Darwish, J Matern Fetal Neonatal Med 2019). The iron content of this lactoferrin supplement was not described by the researchers, but information on the manufacturer's website suggests that each 200-mg dose of MamyVital provides about 31 mg of iron. A similar product available in the U.S. is IronSorb + Lactoferrin by Jarrow Formula, which provides 200 mg of lactoferrin and 18 mg of iron. (Note: This product has not been reviewed by to confirm its ingredients.)

A study in Kenya among 25 infants (average age 4 months), most of whom were iron deficient, found that eating maize porridge fortified with 1.5 mg of iron (as ferrous sulfate) and 1.4 grams of apolactoferrin (a form of lactoferrin with minimal iron) increased iron absorption by 56% compared to eating the iron-fortified meal without lactoferrin. However, eating a meal fortified with lactoferrin as holo-lactoferrin (a form of lactoferrin that is saturated with iron) increased iron levels only as effectively as eating the meal fortified with iron as ferrous sulfate, suggesting no added benefit (Mikulic, J Nutr 2020). Holo-lactoferrin is not the form of lactoferrin included in most lactoferrin supplements available in the U.S. For more information about lactoferrin, particularly its effects on the immune system, see our answer to the question: What is lactoferrin and will it really strengthen my immune system?

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, although it may also decrease iron absorption. Some experts suggest taking iron with a vitamin C-rich food to boost iron absorption and offset this effect. In fact, some iron supplements contain vitamin C as an added ingredient to aid absorption, but some research suggests that it may not 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 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). Green tea (one large, 10 oz cup) was found to cause about an 80% reduction in iron absorption from an iron-containing meal (including iron-enriched bread) as opposed to consuming the meal with mineral water (Lazrak, J Nutr 2021).

Iron absorption also can be reduced by high doses of other minerals, such as zinc, manganese, magnesium or copper. When consuming high-dose mineral supplements, or one of the foods noted above, 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). 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. Interestingly, analysis of U.S. data found that, among women, the risk of stroke actually decreased with intake of iron (from the diet or supplements) up to 20 mg daily, which is similar to the RDA for women up to age 50, although there was no further decrease with higher iron intake. There was no association between dietary iron intake and stroke risk in men (Xu, Int J Environ Health Res 2021). On this basis, it appears prudent to suggest that people should be sure to attain adequate amounts of iron from their diet but 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 may increase iron absorption, although it does not seem to be necessary to take it with iron in order to boost hemoglobin and ferritin levels. Consequently, people who take very high doses of vitamin C (a gram or more daily) may be 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.

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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