The 7 Best Iron Supplements, According to Dietitians

In This ArticleView AllIn This ArticleOur Top PicksReviewsThe Bottom LineChoosing an Iron SupplementOur Search for the Best Iron SupplementsCommon QuestionsOur Trusted Expertise

In This ArticleView All

In This Article

View All

Our Top Picks

Reviews

The Bottom Line

Choosing an Iron Supplement

Our Search for the Best Iron Supplements

Common Questions

Our Trusted Expertise

Photo:EatingWell / Dera Burreson

EatingWell / Dera Burreson

If you find that you’re always cold, tired, or winded more easily during exercise, you might want to get a blood test to check your iron status. If your levels are indeed low, your doctor may likely recommend an iron supplement.

To recommend the best iron supplements on the market we researched the most common brands and spoke to dietitians. To help you get your iron levels back up to a healthy range, consider the picks below, and—remember—always check with your doctor before starting a supplement.

EatingWell’s Supplement Philosophy & Methodology

When should I consider taking iron supplements?If your blood test results show your iron levels aren’t up to par, your doctor will recommend a supplement—and only then should you take an iron supplement. Once you start taking iron pills, you’ll likely notice some of your deficiency symptoms begin to improve. “Generally, the effects of iron supplementation become noticeable within one to three weeks of consistent use,” saysKathleen Benson, RDN, CSSD, a dietitian with Top Nutrition Coaching. This can vary depending on individual health conditions and the severity of your iron deficiency, though.If you haven’t undergone lab tests to assess your need for iron supplementation, you should avoid iron supplements, Benson says. People living with hereditary hemochromatosis, hemosiderosis or those who have a history of hemolytic anemia should also avoid iron pills, Anderson says.

When should I consider taking iron supplements?

If your blood test results show your iron levels aren’t up to par, your doctor will recommend a supplement—and only then should you take an iron supplement. Once you start taking iron pills, you’ll likely notice some of your deficiency symptoms begin to improve. “Generally, the effects of iron supplementation become noticeable within one to three weeks of consistent use,” saysKathleen Benson, RDN, CSSD, a dietitian with Top Nutrition Coaching. This can vary depending on individual health conditions and the severity of your iron deficiency, though.If you haven’t undergone lab tests to assess your need for iron supplementation, you should avoid iron supplements, Benson says. People living with hereditary hemochromatosis, hemosiderosis or those who have a history of hemolytic anemia should also avoid iron pills, Anderson says.

If your blood test results show your iron levels aren’t up to par, your doctor will recommend a supplement—and only then should you take an iron supplement. Once you start taking iron pills, you’ll likely notice some of your deficiency symptoms begin to improve. “Generally, the effects of iron supplementation become noticeable within one to three weeks of consistent use,” saysKathleen Benson, RDN, CSSD, a dietitian with Top Nutrition Coaching. This can vary depending on individual health conditions and the severity of your iron deficiency, though.

If you haven’t undergone lab tests to assess your need for iron supplementation, you should avoid iron supplements, Benson says. People living with hereditary hemochromatosis, hemosiderosis or those who have a history of hemolytic anemia should also avoid iron pills, Anderson says.

Our Top PicksBest Overall:Pure Encapsulations OptiFerin-C at Amazon$26Jump to ReviewAlso Great:Thorne Iron Bisglycinate at Amazon$14Jump to ReviewBest Value:Nature Made Iron at Amazon$28Jump to ReviewBest for Anemia:Thorne Ferrasorb at Amazon$24Jump to ReviewBest for Pregnancy:Needed Prenatal Iron at Amazon$21Jump to ReviewBest Vegan:SALEMegaFood Blood Builder at Amazon$17$14Jump to ReviewGentlest on the Stomach:SALEGNC Gentlesorb Iron at Amazon$15$10Jump to Review

Best Overall:Pure Encapsulations OptiFerin-C at Amazon$26Jump to ReviewAlso Great:Thorne Iron Bisglycinate at Amazon$14Jump to ReviewBest Value:Nature Made Iron at Amazon$28Jump to ReviewBest for Anemia:Thorne Ferrasorb at Amazon$24Jump to ReviewBest for Pregnancy:Needed Prenatal Iron at Amazon$21Jump to ReviewBest Vegan:SALEMegaFood Blood Builder at Amazon$17$14Jump to ReviewGentlest on the Stomach:SALEGNC Gentlesorb Iron at Amazon$15$10Jump to Review

Best Overall:Pure Encapsulations OptiFerin-C at Amazon$26Jump to Review

Best Overall:Pure Encapsulations OptiFerin-C at Amazon$26

Best Overall:

Also Great:Thorne Iron Bisglycinate at Amazon$14Jump to Review

Also Great:Thorne Iron Bisglycinate at Amazon$14

Also Great:

Best Value:Nature Made Iron at Amazon$28Jump to Review

Best Value:Nature Made Iron at Amazon$28

Best Value:

Best for Anemia:Thorne Ferrasorb at Amazon$24Jump to Review

Best for Anemia:Thorne Ferrasorb at Amazon$24

Best for Anemia:

Best for Pregnancy:Needed Prenatal Iron at Amazon$21Jump to Review

Best for Pregnancy:Needed Prenatal Iron at Amazon$21

Best for Pregnancy:

Best Vegan:SALEMegaFood Blood Builder at Amazon$17$14Jump to Review

Best Vegan:SALEMegaFood Blood Builder at Amazon$17$14

Best Vegan:

SALE

Gentlest on the Stomach:SALEGNC Gentlesorb Iron at Amazon$15$10Jump to Review

Gentlest on the Stomach:SALEGNC Gentlesorb Iron at Amazon$15$10

Gentlest on the Stomach:

Best OverallPure Encapsulations OptiFerin-CPHOTO: Amazon$26 at Amazon$15 at WalmartType:Iron bis-glycinate |Amount per serving:28 mg (156% DV) |Independently verified:Yes |In-house tested:Yes |Price:$21 |Form:CapsuleWhat we like:This supplement contains a highly absorbable form of iron plus vitamin C to further increase the iron’s absorption; plus, it’s independently verified and free of unnecessary additives.What to know:One small pill delivers 156 percent of your daily value for iron.Pure Encapsulations has a reputation for high-quality, independently verified products, and this iron supplement is no exception. Pure Encapsulations OptiFerin-C is formulated with iron bis-glycinate, a type of iron known for its easy digestibility. “This supplement also includes vitamin C for better absorption and a trace amount of calcium, which adds to its gentleness without significantly impacting iron absorption,” says Benson.You’ll get 28 milligrams or 156 percent of your daily value (DV) for iron in one small pill. Pure Encapsulations crafts its capsules without unnecessary coatings, bindings, fillers or preservatives, and they’re vegan and free of gluten, artificial flavors and colors and other allergens and ingredients. We also love that the brand tests its ingredients in independent labs and holds its ingredient suppliers to high testing and quality criteria to ensure their supplements' purity and potency.PHOTO: EatingWell / Dera BurresonPHOTO: EatingWell / Dera BurresonPHOTO: EatingWell / Dera Burreson

Best OverallPure Encapsulations OptiFerin-CPHOTO: Amazon$26 at Amazon$15 at Walmart

Best OverallPure Encapsulations OptiFerin-C

Best Overall

Pure Encapsulations OptiFerin-C

PHOTO: Amazon

$26 at Amazon$15 at Walmart

Type:Iron bis-glycinate |Amount per serving:28 mg (156% DV) |Independently verified:Yes |In-house tested:Yes |Price:$21 |Form:Capsule

What we like:This supplement contains a highly absorbable form of iron plus vitamin C to further increase the iron’s absorption; plus, it’s independently verified and free of unnecessary additives.

What to know:One small pill delivers 156 percent of your daily value for iron.

Pure Encapsulations has a reputation for high-quality, independently verified products, and this iron supplement is no exception. Pure Encapsulations OptiFerin-C is formulated with iron bis-glycinate, a type of iron known for its easy digestibility. “This supplement also includes vitamin C for better absorption and a trace amount of calcium, which adds to its gentleness without significantly impacting iron absorption,” says Benson.

You’ll get 28 milligrams or 156 percent of your daily value (DV) for iron in one small pill. Pure Encapsulations crafts its capsules without unnecessary coatings, bindings, fillers or preservatives, and they’re vegan and free of gluten, artificial flavors and colors and other allergens and ingredients. We also love that the brand tests its ingredients in independent labs and holds its ingredient suppliers to high testing and quality criteria to ensure their supplements' purity and potency.

PHOTO: EatingWell / Dera BurresonPHOTO: EatingWell / Dera BurresonPHOTO: EatingWell / Dera Burreson

Also GreatThorne Iron BisglycinatePHOTO: Amazon$14 at Amazon$14 at TargetView on Thorne.com

Also GreatThorne Iron Bisglycinate

Also Great

Thorne Iron Bisglycinate

$14 at Amazon$14 at TargetView on Thorne.com

Type:Iron bis-glycinate |Amount per serving:25 mg (139% DV)  |Independently verified:Yes |In-house tested:Yes |Price:$14 |Form:Capsule

What we like:They’re NSF-Certified for Sport and contain a highly absorbable form of iron that’s associated with fewer side effects.

What to know:It doesn’t contain vitamin C, which helps to maximize iron absorption.

Thorne’s iron supplement is an excellent choice for those who prefer pure iron without additional ingredients. It’s NSF Certified, which means this supplement has been tested for and is free of unsafe levels of contaminants and prohibited substances for athletes. “Renowned for its quality, Thorne offers a straightforward, high-quality iron solution,” Benson says.

Best ValueNature Made IronPHOTO: Amazon$28 at Amazon$11 at Target$11 at Target

Best ValueNature Made Iron

Best Value

Nature Made Iron

$28 at Amazon$11 at Target$11 at Target

Type:Ferrous sulfate |Amount per serving:65 mg (361% DV) |Independently verified:Yes |In-house tested:unknown |Price:$18 |Form:Tablet

What we like:These are very budget-friendly (you get a 6-month supply in a bottle) and contain a high dose of iron to help correct a deficiency.

What to know:They contain a form of iron that may cause gastro issues such as constipation.

Just because these are very affordable, doesn’t mean you’re skimping out on quality. Nature Made’s iron supplement is USP-verified, which means it only contains the ingredients listed on the label in the stated amounts, and it’s free of unsafe levels of contaminants such as heavy metals, pesticides and microbes. The iron in this supplement is ferrous sulfate, a form that may cause gastrointestinal issues like nausea or constipation. Drinking plenty of water andfocusing on fibercan help keep things moving along, but if you’re dealing with persistent symptoms, check with your doctor about changing your dosing.

Best for AnemiaThorne FerrasorbPHOTO: Amazon$24 at Amazon$24 at Walmart$24 at Thrive Market

Best for AnemiaThorne Ferrasorb

Best for Anemia

Thorne Ferrasorb

$24 at Amazon$24 at Walmart$24 at Thrive Market

Type:Iron bis-glycinate |Amount per serving:36 mg (200% DV) |Independently verified:Yes |In-house tested:Yes |Price:$24 |Form:Capsule

What we like:It contains multiple nutrients for an all-around comprehensive anemia supplement.

What to know:It offers a lower dose of iron than other supplements, so you may have to take up to three capsules daily (under the guidance of your doctor).

Each easy-to-take capsule packs 36 mg or 200 percent of your iron DV, helping to build your hemoglobin, correct anemia and bust symptoms like fatigue, lack of focus, brittle nails and cold hands and feet with continued use. Plus, Thorne’s supplement is NSF-certified and free of unsafe contaminants. The instructions recommend taking one to three capsules daily but check with your doctor for specific recommendations on dosing to correct your anemia before starting a supplement.

Best for PregnancyNeeded Prenatal IronPHOTO: Needed$21 at AmazonView on Thisisneeded.comType:Iron bis-glycinate |Amount per serving:13.5 mg (50% DV) |Independently verified:Yes|In-house tested:Yes |Price:$20 |Form:CapsuleWhat we like:It contains a lower dose of iron, which allows you to tailor the dosage to your specific pregnancy or prenatal needs.What to know:If you’re on a multivitamin, you’ll have to take this iron pill separately as it can interact with other nutrients.Benson recommends Needed’s iron supplement because it’s tailored for expectant mothers. “It features the same iron form as Thorne’s Iron Bisglycinate but at a lower dose of 13.5 mg,” Benson says. “This accounts for half the recommended daily intake during pregnancy, offering the flexibility to double up on the dosage with an additional capsule if necessary, especially if your dietary iron intake is limited due to pregnancy-related food aversions.“Needed offers a handy chart with recommendations for the optimal dosing based on the stage you’re in—for example, take one capsule per day during preconception and your first trimester and two capsules per day during your second and third trimester—but always check with your doctor before starting a supplement, especially if you’re pregnant or planning to get pregnant. What’s more, Needed is independently verified and contains a form of iron that’s bioavailable and easy on the stomach, which is particularly important if you’re already dealing with GI issues during your pregnancy.Just note that if you take a prenatal multivitamin, you’ll have to take this iron supplement separately as iron can interact with other nutrients. For instance, calcium will inhibit iron’s absorption. You should take your iron two hours before or after other supplements and some medications.PHOTO: EatingWell / Dera BurresonPHOTO: EatingWell / Dera BurresonPHOTO: EatingWell / Dera Burreson

Best for PregnancyNeeded Prenatal IronPHOTO: Needed$21 at AmazonView on Thisisneeded.com

Best for PregnancyNeeded Prenatal Iron

Best for Pregnancy

Needed Prenatal Iron

PHOTO: Needed

$21 at AmazonView on Thisisneeded.com

Type:Iron bis-glycinate |Amount per serving:13.5 mg (50% DV) |Independently verified:Yes|In-house tested:Yes |Price:$20 |Form:Capsule

What we like:It contains a lower dose of iron, which allows you to tailor the dosage to your specific pregnancy or prenatal needs.

What to know:If you’re on a multivitamin, you’ll have to take this iron pill separately as it can interact with other nutrients.

Benson recommends Needed’s iron supplement because it’s tailored for expectant mothers. “It features the same iron form as Thorne’s Iron Bisglycinate but at a lower dose of 13.5 mg,” Benson says. “This accounts for half the recommended daily intake during pregnancy, offering the flexibility to double up on the dosage with an additional capsule if necessary, especially if your dietary iron intake is limited due to pregnancy-related food aversions.”

Needed offers a handy chart with recommendations for the optimal dosing based on the stage you’re in—for example, take one capsule per day during preconception and your first trimester and two capsules per day during your second and third trimester—but always check with your doctor before starting a supplement, especially if you’re pregnant or planning to get pregnant. What’s more, Needed is independently verified and contains a form of iron that’s bioavailable and easy on the stomach, which is particularly important if you’re already dealing with GI issues during your pregnancy.

Just note that if you take a prenatal multivitamin, you’ll have to take this iron supplement separately as iron can interact with other nutrients. For instance, calcium will inhibit iron’s absorption. You should take your iron two hours before or after other supplements and some medications.

Best VeganMegaFood Blood BuilderPHOTO: Amazon$17$14 at Amazon$15 at Target$15 at WalmartType:Iron bis-glycinate |Amount per serving:26 mg (144% DV) |Independently verified:No |In-house tested:Yes |Price:$15 |Form:TabletWhat we like:It contains vitamin C for greater iron absorption as well as B vitamins for blood support.What to know:It’s not independently verified but the brand tests its supplements for herbicides and pesticides.Supplements often contain animal-derived ingredients, such as gelatin, so if you’re on a vegan diet, you’ll have to be extra careful to pick a product that fits your needs. And also, vegans and vegetarians are at agreater risk for iron deficiencybecause the best food sources of iron are animal proteins.MegaFood’s Blood Builder is a great food-derived vegan supplement ​​that can support red blood cell formation and total-body health without GI-related side effects. “It not only includes a gentle form of iron but also enriches it with a blend of fruits and vegetables, vitamin C for enhanced absorption, and other blood-supportive ingredients like folate and B12,” Benson says. The serving size is just one tablet per day, which includes 26 mg (or 144 percent DV) of iron bis-glycinate.PHOTO: EatingWell / Dera BurresonPHOTO: EatingWell / Dera BurresonPHOTO: EatingWell / Dera Burreson

Best VeganMegaFood Blood BuilderPHOTO: Amazon$17$14 at Amazon$15 at Target$15 at Walmart

Best VeganMegaFood Blood Builder

Best Vegan

MegaFood Blood Builder

$17$14 at Amazon$15 at Target$15 at Walmart

Type:Iron bis-glycinate |Amount per serving:26 mg (144% DV) |Independently verified:No |In-house tested:Yes |Price:$15 |Form:Tablet

What we like:It contains vitamin C for greater iron absorption as well as B vitamins for blood support.

What to know:It’s not independently verified but the brand tests its supplements for herbicides and pesticides.

Supplements often contain animal-derived ingredients, such as gelatin, so if you’re on a vegan diet, you’ll have to be extra careful to pick a product that fits your needs. And also, vegans and vegetarians are at agreater risk for iron deficiencybecause the best food sources of iron are animal proteins.

MegaFood’s Blood Builder is a great food-derived vegan supplement ​​that can support red blood cell formation and total-body health without GI-related side effects. “It not only includes a gentle form of iron but also enriches it with a blend of fruits and vegetables, vitamin C for enhanced absorption, and other blood-supportive ingredients like folate and B12,” Benson says. The serving size is just one tablet per day, which includes 26 mg (or 144 percent DV) of iron bis-glycinate.

Gentlest on the StomachGNC Gentlesorb IronPHOTO: Amazon$15$10 at Amazon$15 at WalmartView on Gnc.com

Gentlest on the StomachGNC Gentlesorb Iron

Gentlest on the Stomach

GNC Gentlesorb Iron

$15$10 at Amazon$15 at WalmartView on Gnc.com

Type:Hydrolyzed protein chelate |Amount per serving:18 mg (100% DV) |Independently verified:Yes |In-house tested:unknown |Price:$15 |Form:Capsule

What we like:It contains a well-tolerated form of iron at a lower dose to minimize GI side effects.

What to know:It doesn’t contain vitamin C for better iron absorption.

GNC Gentlesorb Iron, with its chelated iron formulation, is an excellent choice for those with sensitive stomachs, Benson says. “This type of iron is known for its quick absorption and reduced likelihood of causing gastrointestinal discomfort,” she says, adding that the moderate dosage of 18 mg (100% DV) further aids in minimizing any potential stomach upset.

The Bottom Line: The Best Iron Supplement

Pure Encapsulations OptiFerin-C(view at Amazon) won the top spot on our list because it’s independently verified and formulated with a highly absorbable form of iron as well as contains vitamin C to maximize iron absorption.Thorne Iron Bisglycinate(view at Amazon) is another solid option because it’s NSF-Certified for Sport and contains a highly absorbable form of iron that’s less likely to cause GI issues.

Select your preferred form

Liquid iron supplements are also easily absorbed and not as hard on the gut but come with a higher risk of taking too much since the dosage can be more difficult to measure.

Gummies are easy to take, but most types contain extra ingredients (like added sugar and gelatin) and may require more servings to meet requirements for those with iron-deficiency anemia, Anderson says.

It’s also important to consider the type of iron in your supplement. According to Benson, the most common types of supplemental iron include:

Look for independent verification

Read the ingredients

When shopping for an iron supplement, prioritize those that are primarily composed of iron or include iron combined with vitamin C for enhanced absorption, Benson says. “While supplements with a blend of herbs and other ingredients exist, simpler formulations are often more evidence-based and safer,” she says.

You’ll also want to be wary of unnecessary additives and fillers that may not contribute to the supplement’s effectiveness or could cause adverse reactions. “Reading labels carefully and consulting with a healthcare provider is advisable, particularly for those with specific health concerns or dietary needs,” Benson says.

What are the signs and symptoms of iron deficiency?

Symptoms ofiron deficiency anemiainclude fatigue, weakness, change in mood or motivation and focus, headache, dizziness, shortness of breath, pale skin, cold hands and feet, brittle nails, fast heartbeat or chest pain, unusual cravings (like for ice or dirt), tongue soreness and poor recovery from exercise.

If you think you’re low on iron, visit your doctor for a blood test to check your iron levels.  “Results of the lab work will determine the need and appropriate iron dosage,” Anderson says.

How can I get enough iron from food?

When is the best time to take iron supplements?

Theoptimal time to take iron supplementsis usually on an empty stomach, or at least 2 hours after a meal, to enhance absorption, Benson says.

You’ll also want to avoid taking your supplement hours after a workout. Hepcidin is a peptide hormone that reduces iron absorption, and it peaks about 3 to 6 hours after exercise, Anderson says. So take iron supplements in the morning to avoid hepcidin and before or as close to the completion of exercise as possible.

But if you get gastrointestinal side effects, it may be helpful to reduce the dose or take the supplement closer to meal times. If you have iron deficiency, avoid consuming coffee, tea, dairy products and calcium supplements one hour before or two hours after taking iron supplements, as these can interfere with iron absorption, Benson says.

Do iron supplements cause constipation?

Iron supplements can cause constipation due to their osmotic effect—e.g., they draw water away from the lower gastrointestinal tract, which can result in harder stools, Benson says.

Taking iron supplements on an empty stomach is recommended, but doing so may increase your risk of getting constipation. If you find that your iron supplement is constipating you and causing GI distress, try taking it with a meal and increase your intake of fiber-rich foods (fruits, whole grains, nuts, veggies, legumes), drink plenty of water, and engage in regular physical activity, Anderson says.

You might also try switching to a different form of iron like iron bis-glycinate, which is associated with fewer gastrointestinal side effects and may help some people avoid constipation.

What are some of the other side effects of iron supplements?

Contact your doctor if you experience severe or persistent symptoms such as constipation, stomach pain, diarrhea, nausea or teeth staining, Benson says. If you’re experiencing ongoing side effects, your doctor might switch you to a different supplement, have you take it closer to mealtime, or recommend you take the supplement a few times a week rather than daily.

Iron supplements usually contain more iron than the body can absorb. Because of this, a large amount of iron ends up sticking around in the intestinal tract, and some research shows that this can potentially lead to the production of free radicals and inflammation, Anderson says.

“It’s also important to highlight that accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6 years of age,” Benson says. Always keep these supplements out of reach of children. In the event of an accidental overdose, immediately contact a healthcare professional or a poison control center. Ensuring the safe use and storage of iron supplements is crucial for health and safety, especially in households with young children.

Can I take iron supplements with other medications?

Iron supplements interact with many different types of medications, including nonsteroidal anti-inflammatory drugs (NSAIDs), allopurinol (Zyloprim), penicillamine, drugs that treat GERD and other stomach issues and antacids. Aim to take your iron pills at least 2 hours before or 2 hours after taking these medications.

“It’s crucial to inform your healthcare provider about all prescription and non-prescription medications, vitamins, supplements, and herbal products you are currently using or planning to use, to avoid any potential adverse interactions,” Benson says.

April Benshosanhas been reporting on nutrition, health, and expert-recommended products from the start of her journalism career. She interviewed two registered dietitians for their top picks and asked them what to look for in a quality supplement:

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SourcesEatingWell uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable and trustworthy.Camaschella C. Iron deficiency.Blood. 2019;133(1):30-39. doi: 10.1182/blood-2018-05-815944

Sources

EatingWell uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable and trustworthy.Camaschella C. Iron deficiency.Blood. 2019;133(1):30-39. doi: 10.1182/blood-2018-05-815944

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

Camaschella C. Iron deficiency.Blood. 2019;133(1):30-39. doi: 10.1182/blood-2018-05-815944