The 7 Best Iron Supplements of 2022, According to a Dietitian

Thorne Iron Bisglycinate is our top pick

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Best Iron Supplements

Verywell / Sabrina Jiang

Iron is an essential mineral our bodies need to carry oxygen and support growth, cell functioning, and brain development. Getting the right amount of iron is important, as too little or too much can be dangerous. It is best to get your iron from food, as food provides additional benefits such as energy, fiber, other nutrients, and it is unlikely to overload on iron from food sources.

However, you will likely need an iron supplement if you are pregnant, at high risk of iron deficiency due to a health condition or limited diet, or if a healthcare professional confirms you have an iron deficiency, which may cause symptoms such as fatigue, irritability, difficulty concentrating, and a weakened immune system. A more severe iron deficiency may progress to iron deficiency anemia, which can lead to more serious symptoms like dizziness, shortness of breath, and heart problems.

When deciding which iron supplement is best for you, consider appropriate dose, budget, ingredients, and the form of iron that will be absorbed well but not cause you gastrointestinal discomfort. You should only take an iron supplement if it has been recommended by a healthcare provider.

Verywell Health Approved Iron Supplements

  • Best Overall:  Thorne Iron Bisglycinate is an NSF Sport Certified supplement that provides 25 milligrams of iron in a form that the body can readily use in one convenient capsule.
  • Best High Dose: If your healthcare provider has recommended a high dose iron supplement to correct a deficiency, we recommend trying USP Certified, Nature Made Iron, containing 65 milligrams.

Always speak with a healthcare professional before adding a supplement to your routine to ensure that the supplement is appropriate for your individual needs and which dosage to take.

Is an Iron Supplement Beneficial?

The effectiveness of iron supplements depends on what is causing the deficiency, which should be determined by a healthcare professional. If the cause of the deficiency is a gastrointestinal disorder that makes it more difficult for your body to absorb nutrients, then supplementing won't work until the disorder is managed. Iron supplements are less effective if you do not take the supplement as prescribed.

The following types of people may benefit from taking an iron supplement:

  • Those with diagnosed deficiency. Those at highest risk for deficiency include: young children; women of reproductive age; individuals who experience heavy menstrual bleeding; frequent blood donors; those who follow a vegetarian or vegan diet; and people with cancer, kidney failure, gastrointestinal disorders, or heart failure. While other ways of supplementing are sometimes necessary, oral iron supplements are often effective in correcting iron deficiency and iron deficiency anemia.
  • Babies. Babies need iron supplementation through iron-fortified formula, foods, or supplements starting at 4 to 6 months of age. Talk to your healthcare provider to determine the best supplementation method for your baby.
  • Pregnant people. People experiencing pregnancy have increased iron needs. Supplementing with iron helps prevent iron deficiency and reduce the risk of anemia.
  • Some athletes. Endurance athletes—females in particular—may be at greater risk of iron deficiency. Iron supplementation among athletes with a known deficiency may improve performance. Please note: If you area an athlete without an iron deficiency, iron supplementation will not improve your performance, and a supplement is not recommended.

Who May Not Benefit From an Iron Supplement

If you get enough iron from your diet and do not have a confirmed deficiency or increased need, you should not use iron supplements, as there is risk of toxicity. You will also want to be wary of taking an iron supplement if you:

  • Are at risk of iron overload. Healthy postmenopausal women and adult men should typically avoid iron supplements, as well as those with hemochromatosis, a hereditary condition that results in the absorption of excessive amounts of dietary iron.
  • Are on proton pump inhibitors. If you have an iron deficiency and also use proton pump inhibitors, you may not respond well to oral iron supplementation. This is because proton pump inhibitors reduce stomach acid, which is involved in iron absorption. Talk to a healthcare provider to decide the best supplementation route for you.
  • Have malabsorptive conditions. If you have a condition that results in your body having trouble absorbing nutrients, such as celiac disease, you may not be able to adequately absorb oral iron supplements until the disorder is managed.
  • Take medications that interact with iron supplements. It is best to consult with your healthcare provider to discuss any potential interactions before beginning iron supplementation. These supplements reduce absorption of levodopa, found in medications that treat Parkinson’s disease and restless leg syndrome. Iron can also reduce the effectiveness of levothyroxine, found in medications used to treat hypothyroidism, goiter, and thyroid cancer.

Best Overall: Thorne Iron Bisglycinate

Thorne Research Iron Bisglycinate

Walmart

Pros
  • NSF Certified for Sport

  • Form of iron is easily absorbed and gentle on the stomach

  • 139% of daily value of iron

Cons
  • Expensive

We like that Thorne Iron Bisglycinate checks so many boxes in our methodology, making it a trusted option. Thorne’s supplement may be an especially great choice for athletes who have been diagnosed with a mild deficiency. It is NSF Certified for Sport, which means it undergoes NSF certified testing (verifying contents and ensuring only safe levels of contaminants), as well as additional athlete-specific testing to ensure there are no prohibited substances or masking agents.

Each Thorne capsule contains 25 milligrams of iron bisglycinate, a form of iron that is readily absorbed and typically does not result in gastrointestinal side effects, such as nausea and constipation. The amount contained in these capsules provides 139% of the average person's daily value of iron. Often, this is not enough to correct a more severe deficiency, so check with your healthcare provider to see if this supplement might be a good fit for your needs.

As an added benefit, Thorne's capsules are also free from gluten, dairy, and soy. Its facilities are CGMP certified, which ensures they are compliant with the FDA's Current Good Manufacturing Practices that regulate the way in which products are produced and standardized. Thorne's facilities also have an A rating from Australia’s Therapeutic Goods Administration (TGA), the country's administration for regulating dietary supplements.

Form: Capsule | Type: Iron bisglycinate | Dose: 25 mg | Recommended Use: Once daily | Third-Party Certified: Yes

Best GI Friendly: NOW Iron 18 mg Veg Capsules

NOW Supplements Iron

Walmart

Pros
  • ConsumerLab tested and approved

  • Form of iron is easily absorbed and gentle on the stomach

  • Vegan

Cons
  • Lower dose of iron may not correct deficiency

We love that NOW's vegan-friendly iron supplement contains ferrous bisglycinate, a form of iron that causes less stomach discomfort. Taking it with food can make it even more comfortable on the belly.

You can take this supplement for iron in your vegan or vegetarian diet, and it is also non-GMO certified. NOW's supplements contain only 18 milligrams of iron. While this is the daily requirement for women ages 19–50, it may not be enough to correct an iron deficiency. Your healthcare provider will recommend an appropriate dose based on your needs.

Form: Capsule | Type: Ferrous bisglycinate | Dose: 18 mg | Recommended Use: Once daily with food | Third-Party Certified: Yes

Best High Dose: Nature Made Iron 65 mg Tablets

Nature Made Iron

Nature Made

Pros
  • Budget friendly

  • USP certified; ConsumerLab tested and approved

  • Contains ferrous sulfate, which is absorbed well

Cons
  • May be uncomfortable on the stomach

If you have a diagnosed iron deficiency, especially one that is severe, your healthcare provider will likely recommend a higher dose supplement. We like Nature Made's ferrous sulfate because it is a high-dose, well-absorbed supplement that has been verified by two reputable third-party organizations—ConsumerLab.com and USP. There are 180 tablets per bottle, making the cost just a few cents per pill.

There is one catch, though. The ferrous sulfate form of iron is more affordable and well-absorbed but more likely to cause stomach discomfort. For that reason, the instructions for use with this supplement recommend taking it with water and a meal, which will be gentle on your stomach.

Nature Made provides a higher dose of iron at 65 milligrams, or 325 milligrams ferrous sulfate. This amount is equivalent to 361% of your daily value of iron. This higher amount may be necessary if you have a deficiency but should be used under a healthcare provider's recommendation and supervision.

Form: Tablet | Type: Ferrous sulfate | Dose: 65 mg | Recommended Use: Once daily with water and a meal | Third-Party Certified: Yes

Best With Vitamin C: Zahler's Iron Complex

Zahler Iron Complex

Walmart

Pros
  • Contains vitamin C to enhance absorption

  • Form of iron is easily absorbed and gentle on the stomach

  • Contains B12, which many people need to supplement

Cons
  • Not third-party tested

  • Other ingredients may not be beneficial

We included Zahler's Iron Complex in our top picks because it contains vitamin C (which some studies show may help enhance absorption of nonheme iron) and vitamin B12 (which people with poor absorption or low intake of animal products need to supplement).

Zahler's contains 25 milligrams of iron bisglycinate (that's the stomach-friendly form we've been talking about) and 60 milligrams f vitamin C to aid in absorption. This supplement also contains 100% of your daily value of folate, 3,000% of your daily value of B12, and the amino acid L-histidine. While some groups benefit from B12 and folate supplementation, less is known about L-histidine supplementation. Please discuss all ingredients with your healthcare provider before beginning this supplement.

While Zahler's iron supplement is not third-party tested, its products are produced in a CGMP-certified facility. Zaher's Iron Complex is also certified kosher, non-GMO, and free from gluten, dairy, and soy.

Form: Capsule | Type: Iron bisglycinate | Dose: 25 mg iron bisglycinate, 60 mg vitamin C, 400 mcg folate, 80 mcg vitamin B12, 100 mcg L-histidine | Recommended Use: Once daily with food | Third-Party Certified: No

Best Liquid: Garden of Life mykind Organics Plant Iron & Organic Herbs

Pros
  • ConsumerLab tested and approved

  • Contains vitamin C to aid absorption

  • Certified organic and vegan

Cons
  • Amount of iron may not correct deficiency

  • Extensive ingredient list

We understand how stressful swallowing pills can be, so we wanted to give you a liquid iron supplement option. Liquid iron is convenient and easy to add to water or juice. Garden of Life mykind Organics Plant Iron & Organic Herbs contains iron from an organic food blend, along with vitamin C, vitamin B12, and vitamin B6. This liquid supplement contains 10 milligrams of iron, which is up to 55% of the daily value. The dose may not be adequate for those with iron deficiency or anemia, so consult with your healthcare provider.

This supplement is made entirely from whole food ingredients. However, the ingredient list is extensive and includes herbs. Be sure to read the entire list and show it to your healthcare provider to check for allergens and potential interactions with your other medications or supplements.

This supplement is certified organic, gluten-free, and vegan and may be more palatable than other liquid options.

Form: Liquid | Type: Organic whole food blend | Dose: 10 mg iron, 15 mg vitamin C, 2 mg vitamin B6, 100 mcg vitamin B12, | Recommended Use: 10 ml daily directly or mixed into water or juice | Third-Party Certified: Yes

Best Vegan: Country Life Easy Iron 25 mg Capsules

Country Life Easy Iron

Walmart

Pros
  • ConsumerLab tested and approved

  • Suitable for vegans and vegetarians

  • Form of iron is easily absorbed and gentle on the stomach

Cons
  • Does not contain vitamin C for added absorption

Country Life's Easy Iron is certified vegan by the American Vegetarian Association. It provides 25 milligrams of ferrous bisglycinate, a form of iron that is typically gentle on the stomach. Easy Iron is also certified gluten-free, kosher, and non-GMO—and the company is a certified B corporation that uses renewable energy in their manufacturing practices.

Country Life recommends taking the pill with food, and we recommend pairing it with a vitamin C-rich food or drink (like orange juice) for enhanced absorption.

Form: Capsule | Type: Ferrochel ferrous bisglycinate | Dose: 25 mg | Recommended Use: Once daily (if possible, with food) | Third-Party Certified: Yes

Best Chewable: VegLife Vegan Iron Chewable Tablets

VegLife Vegan Iron Chewable Tablets

iHerb

Pros
  • ConsumerLab tested and approved

  • Suitable for vegans

  • Convenient chewable tablets

Cons
  • Dose may not correct iron deficiency

  • Contains sugar alcohols

  • Extensive ingredient list

If you dislike swallowing pills, you may prefer taking your iron supplements in chewable form. VegLife's Vegan Iron Chewable Tablets provide 18 milligrams of iron as iron glycerinate. In addition to iron, these chewables also contain vitamin C, folic acid, vitamin B12, and a blend that includes spinach, parsley, dandelion, alfalfa, and rose hips. They are sugar free and suitable for vegans.

Vegans and some vegetarians need to supplement with B12, so check with your healthcare provider to see if this supplement may be able to also serve as your B12 supplement. Since this option contains other nutrients, herbs, and sugar alcohols, it is especially important to show the label to your healthcare provider. They can cross-check the ingredients with any other supplements and medications you're taking.

VegLife's Vegan Chewable Tablets contain 18 milligrams of iron, the daily requirement for premenopausal women. This dose may not be high enough to correct a deficiency.

Form: Tablet | Type: Ferrous fumarate | Dose: 18 mg | Recommended Use: One chewable once daily | Third-Party Certified: Yes

Final Verdict

The correct iron supplement for you will depend on the dose you need. However, Thorne's Iron Bisglycinate (view at Amazon) is an excellent iron supplement. In addition to being less likely to cause stomach discomfort, it is safe for athletes and has NSF Certified for Sport, CGMP, and TGA certifications. For a more affordable, higher-dose option, consider Nature Made (view at Amazon). The supplement holds two third-party verifications and may be more appropriate to correct a deficiency.

How We Select Supplements

Our team works hard to be transparent about why we recommend certain supplements; you can read more about our dietary supplement methodology here. 

We support supplements that are evidence-based and rooted in science. We value certain product attributes that we find to be associated with the highest quality products. We prioritize products that are third-party tested and certified by one of three independent, third party certifiers: USP, NSF, or ConsumerLab. 

It's important to note that the FDA does not review dietary supplements for safety and effectiveness before they go to market. Our team of experts has created a detailed, science-backed methodology to choose the supplements we recommend.

What to Look for in an Iron Supplement

Third-Party Testing

Supplements that are third-party tested are sent to a lab where they are tested to ensure they contain what they say they contain and are not contaminated with specific high-risk, common contaminants. However, it’s important to note:

  1. Third party testing does not test to see if a product is effective or safe for everyone, and it does not ensure the supplement will not interact with other supplements or medications.
  2. Not all third-party testing is created equal. It is not uncommon for supplement companies to pay labs for certificates after conducting minimal to no testing. 
  3. The third party certifications we can trust are: ConsumerLab, NSF, and USP. However, these certifications are difficult to obtain and/or expensive for manufacturers, so many companies choose not to get their products tested by one of these three organizations. 
  4. Sometimes products tested by these three companies are more expensive to try to offset the cost they pay for certification.
  5. Just because a supplement is not tested by one of these three companies, it does not mean it’s a bad product. We recommend doing some research on the reputability of the manufacturer, and calling up the manufacturer and their testing lab to determine their protocols and decide if you feel comfortable consuming the supplement.

As there is no single agency responsible for testing supplements, it is also possible that iron supplements do not contain the amount of iron listed on the label. Therefore, you may want to use iron supplements that have been third-party tested. Keep in mind that iron supplements should only be used under the supervision of a licensed healthcare provider.

Form

Dietary iron can be found in two forms:

Heme Iron
  • Found in animal foods such as poultry, seafood, meat

  • More readily absorbed form of iron

Non-heme Iron
  • Found in plant foods, including nuts, beans, vegetables and iron-fortified foods

  • Less readily absorbed form of iron

  • Pairing non-heme sources with vitamin C rich foods or heme sources can increase absorption. 

Supplemental iron can be taken orally via liquid, pills, or gummies or (if recommended) through an IV or intramuscular injection. Typically, it comes as ferrous or ferric iron salts. Ferrous iron in supplements is more readily absorbed than ferric iron.

The amount of elemental iron (the amount of iron the body can absorb) is listed on the product's supplement facts panel.

Ingredients & Potential Interactions

It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included, relative to the recommended daily value of that ingredient. Please bring the supplement label to your healthcare provider to review the different ingredients contained in the supplement and any potential interactions between these ingredients and other supplements and medications you are taking.

In addition to iron, some supplements may contain vitamin C to aid in absorption. They also may contain other vitamins, minerals, and herbs as well as flavors, colors, and preservatives. Be sure to review all ingredients to ensure the supplement meets your individual needs.

Iron supplements can interact with medications containing levodopa or levothyroxine. Use of proton pump inhibitors or calcium supplements may lower the effect of iron supplements.

Iron Dosage

According to the National Institutes of Health, the Recommended Dietary Allowances (RDAs) for iron are as follows:

  • 1-3 Years: 7 mg
  • 4-8 years: 10 mg
  • 9-13 years: 8 mg
  • 14-18 years: Males — 11 mg, Females — 15 mg
  • 19-50 years: Males — 8 mg, Females — 18 mg
  • 51+ years: 8 mg

Note that iron needs for females are higher during menstruating years due to iron loss in blood. Additionally, iron needs differ for infants and for people who are pregnant and lactating. Transgender individuals ages 14-50 should work with their healthcare provider to assess iron needs, which will vary based on menstruation status and other variables.

Recommended supplement doses will vary based on your stage of life. For example, iron supplements are often recommended in pregnancy and infancy in very different doses. Your dosage will also depend on the severity of your iron deficiency, such as a mild deficiency or iron deficiency anemia. Your healthcare provider will recommend an appropriate dose for you.

How Much is Too Much?

Consuming excess supplemental iron can be dangerous. Taking over 20 milligrams per kilogram of body weight can lead to gastric upset, constipation, vomiting, and faintness. Repeated high dose supplementation can cause stomach pain, nausea, vomiting, and, over time, can result in damage to the liver or brain.

The Tolerable Upper Intake Level (UL) for iron refers to the maximum daily amount that can be safely taken. From birth until 13 years, the UL is 40 milligrams. For those 14 years and older, it is 45 milligrams. Unless a deficiency is being treated, no more than 45 milligrams should be taken to avoid harmful side effects and iron overload.

FAQs

Frequently Asked Questions

  • When should I take iron supplements?

    You should only use iron supplements if a medical professional has determined you have an increased need, iron deficiency, or iron deficiency anemia. They will prescribe the proper dosage and regimen.

    Some people struggle to take their prescribed iron supplements each day because they experience stomach discomfort. While those with a severe deficit may need to take an iron supplement daily until the deficiency is corrected, for many people, supplementing every other day may be a great option. This option may reduce stomach discomfort while still effectively correcting the deficiency. If you cannot tolerate oral iron treatments, you may be prescribed iron supplementation through an IV for a period of time.

  • Can iron supplements cause constipation?

    Iron supplements may cause constipation, especially when taken in higher doses of at least 45 milligrams per day. Certain forms of iron may have fewer digestive effects than others. In our product list below, we call out options that are known to be gentle on the stomach.

    To help alleviate constipation, incorporate adequate dietary fiber, fluids, and daily movement. You might also consider using a stool softener.

    "For those who experience constipation during supplementation, I recommend focusing on good hydration and fiber intake. Aim for at least 2 liters of water daily. Fiber recommendations for the average adult range from approximately 25 to 35 grams per day. When increasing fiber in your diet, make sure to go gradually and ensure that you are spreading it out throughout the day for optimal tolerance." — Arielle Leben, RD

  • Can iron supplements cause diarrhea?

    Iron supplements can cause diarrhea in some people, especially when high doses are taken on an empty stomach. You may be able to reduce this risk by selecting certain forms of iron, such as iron bisglycinate (which is gentle on your stomach) or taking iron supplements with food.

  • How should I take iron supplements for best absorption?

    Supplemental iron comes in various forms, including capsules, liquid, chewable tablets, and gummies. According to Jamie Gershel, MS, RD, “The best way to make sure your iron supplement is working for you is to take iron on an empty stomach with water. If that is not an option, pair your iron pill with vitamin C-rich foods or a cup of orange juice.”

    It is also important to take iron supplements separately from calcium, tea, zinc, and antacids, as these items can inhibit absorption.

  • How soon after taking iron supplements will I feel better?

    Most people will feel better within a few days to about three weeks, although it can take longer depending on your needs and the cause of deficiency. It is important to continue with iron supplementation as prescribed until iron stores are restored.

Why Trust Verywell Health

Tamar Kane, MS, RD is a registered dietitian and marathon runner. Tamar has her master's degree in nutrition and exercise physiology from Teachers College, Columbia University. She specializes in working with plant-based athletes, one of the populations at highest risk for iron deficiency. Her goal is to help people understand how to properly fuel their bodies (and supplement, if needed!) to optimize performance and well-being.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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