The 7 Best Iron Supplements of 2020, According to a Dietitian

Replete iron levels with our top picks

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First Look

Best Overall: Slow Fe Iron Tablets at Walmart

"The high potency, slow-release tablets replete iron levels without common gastrointestinal side effects."

Best Liquid: Floradix Iron + Herbs at Amazon

"Plant-based Floradix Iron + Herbs is a great tasting liquid iron supplement that is rich in b-vitamins"

Best Tablet: Feosol Complete with Bifera Iron Caplets at Amazon

"The unique dual iron formula offers both heme and non-heme iron to enhance absorption while minimizing side effects."

Best with Vitamin C: Pure Encapsulations Iron-C at Amazon

"Pure Encapsulations Iron-C combines two forms of vitamin C with iron to provide the body with highly absorbable iron in one capsule."

Best Organic: New Chapter Iron Food Complex at Amazon

"The fermented iron derived from whole food ingredients is easy to digest and adds powerful probiotics to your system in the form of lactic acid bacteria."

Best Vegan: Floradix Floravital Iron + Herbs at Amazon

"The liquid formula contains 10mg of iron as ferrous gluconate and is free from yeast, honey, and gluten."

Best Budget: Nature Made Iron Tablets at Amazon

"One bottle of Nature Made Iron tablets contains a 180-day supply of high quality iron supplements."

Iron deficiency is one of the most common nutritional deficiencies in the world, affecting approximately 2 billion people. Iron is needed in the body to make hemoglobin, a substance in red blood cells that helps to distribute oxygen throughout the body. Without adequate iron, a person may develop iron-deficiency anemia.

While including iron-rich foods in your diet, such as turkey, chicken, and pumpkin seeds, is a great defense against anemia, supplementation may be necessary. Iron supplements come in many forms such as liquid, capsules, tablets, and in some cases, intravenous iron.

There are many types of iron used in supplements, the most common of which are ferrous sulfate and ferrous gluconate. Ferrous sulfate is the form best absorbed by the body. It is important to note that there is a difference between “ferrous sulfate” and “elemental iron.” For example, a supplement may contain 325 milligrams (mg) of ferrous sulfate and 65mg of elemental iron. Always ask your physician for the recommended dose in both elemental iron and ferrous sulfate forms to ensure you select a supplement with the correct dosage.

Our Top Picks

Best Overall: Slow Fe Iron Tablets

Slow Fe iron supplement

 Courtesy of Target

The high potency, slow-release tablets replete iron levels without common gastrointestinal side effects. Many iron supplements can cause side effects such as nausea and abdominal discomfort. The controlled release system delivers iron to the body slowly, which is gentler on the stomach.

Each easy-to-swallow pill provides 45mg of elemental iron, which is equivalent to 142mg of ferrous sulfate. Ferrous sulfate is a form of iron that is highly absorbable and most recommended by doctors. The once-daily Slow FE tablets are widely available and budget-friendly, plus they have fewer side effects.

Possible Side Effects

"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 ~25-35 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, a registered dietitian at the IBD Center at NYU Langone Health

Best Liquid: Floradix Iron + Herbs

If you dislike tablets and capsules, liquid is an effective alternative. The plant-based Floradix Iron + Herbs is a great tasting liquid iron supplement that is rich in B-vitamins.

There are two types of iron: heme iron that is typically found in protein-containing foods and non-heme iron found in plants and supplements. Heme iron is typically absorbed more efficiently than non-heme iron; however, some nutrients such as vitamin C and B12 may help to increase non-heme iron absorption. By adding B vitamins including thiamin, riboflavin, B6 and B12 to the mixture, Floradix is easily absorbed and non-constipating.

Each 10mL serving contains 10 calories, 2g of sugar and 10mg of iron in the form of ferrous gluconate. Floradix is a vegetarian, preservative-free, and alcohol-free. Note that this product must be refrigerated after opening and it should be consumed within 4 weeks.

Good to Know

"You may notice a change in stool color after starting supplementation. Iron may darken stool and this is usually nothing to be alarmed by. However, it is important to communicate any changes in stool color to your doctor as darker stools may also indicate intestinal bleeding." Arielle Leben, registered dietitian at the IBD Center at NYU Langone Health

Best Tablet: Feosol Complete with Bifera Iron Caplets

Feosol Complete with Bifera is a once-daily caplet that can be taken at any time of day, with or without food. The gentle iron is perfect for sensitive stomach and each caplet provides a total of 28mg of iron.

The unique dual iron formula differs from typical iron supplements, as it offers both heme and non-heme iron to enhance absorption while minimizing gastrointestinal side effects. The heme iron source, or HIP, is made up of Proferrin, a high-quality heme iron polypeptide. The non-heme iron is in the form of polysaccharide iron complex.

Best with Vitamin C: Pure Encapsulations Iron-C

Vitamin C, also known as ascorbic acid, can help to enhance the absorption of iron. Pure Encapsulations Iron-C combines two forms of vitamin C (ascorbic acid and ascorbyl palmitate) with iron to provide the body with highly absorbable iron in one capsule. The combination of water-soluble and fat-soluble vitamin C promotes optimal absorption of the iron.

Pure Encapsulations recommends 1–2 capsules daily, in divided doses, between meals. Each capsule contains 15mg of iron, half as iron glycinate and half as iron aspartate. These forms of iron are known as "chelated iron" that pass through the digestive system without being broken down for more efficient absorption in the small intestine.

Pure Encapsulations is a trusted brand known for its superior hypo-allergenic dietary supplements. Iron-C is also vegan, gluten-free, and non-GMO.

"While you can choose to get vitamin C from a supplement, there are also great dietary sources such as citrus, strawberries, and kiwi. Be cautious with grapefruit, though, as it is contraindicated with certain medications such as statins." Arielle Leben, registered dietitian at the IBD Center at NYU Langone Health

Best Organic: New Chapter Iron Food Complex

The ICS-Certified Organic Iron Food Complex from New Chapter provides 9mg of whole food fermented iron in the form of ferrous fumarate in each tablet. Each once-daily tablet can be taken at any time of day, with or without food. The fermented iron derived from whole food ingredients is easy to digest and adds powerful probiotics to your system in the form of lactic acid bacteria.

New Chapter's Iron Food Complex supports optimal absorption of iron by adding complementary nutrients including vitamin C, vitamin E, folate, and B12. The tablets also contain herbs to support stress, energy, and digestion. These herbs include maca, chamomile, peppermint, ginger, turmeric, and aloe.

Note that the tablets contain fermented soy and wheat as a food source for the probiotic; however, the tablets are gluten-free.

Iron Supplementation During Pregnancy

If your doctor has recommended iron supplementation while you are expecting, be sure to consider form, dosage, and side effects when purchasing. A slow-release tablet may be better tolerated and help to avoid common pregnancy complaints such as constipation and nausea.

Note that your prenatal likely has iron in it, so consider that amount when looking at additional supplementation.

Best Vegan: Floradix Floravital Iron + Herbs

Floravital is the vegan version of the popular liquid iron supplement, Floradix Iron + Herbs. The liquid formula contains 10mg of iron as ferrous gluconate and is free from yeast, honey, and gluten. This vegan version is also best for people with yeast or gluten intolerances, as well as those with candida.

The blend of fruit juice concentrates, herbs, and complementary B vitamins creates a delicious, easily absorbed iron supplement that delivers essential iron for vegans and vegetarians. The vegan diet may be lacking in certain nutrients such as iron, so selecting an effective supplement is important.

Floravital is preservative-free and alcohol-free. Note that this product must be refrigerated after opening and should be consumed within 4 weeks.

"Calcium may inhibit the absorption of iron. Avoid drinking milk or taking calcium and antacids at the same time as your iron supplement." Arielle Leben, registered dietitian at the IBD Center at NYU Langone Health

Best Budget: Nature Made Iron Tablets

One bottle of Nature Made Iron tablets contains a 180-day supply of high-quality iron supplements. With no synthetic dyes, artificial flavors, preservatives, starch, or yeast, Nature Made Iron supplements are a clean, budget-friendly choice.

Nature Made Iron is USP Verified. This indicates that the ingredients on the label are true to what is in the supplement, the supplement doesn't contain harmful levels of contaminants, the supplement will break down properly, and it is made in accordance with current FDA Good Manufacturing Practices.

Each tablet provides 65mg of elemental iron which is equivalent to 325mg ferrous sulfate. Nature Made recommends taking one tablet daily with water and a meal.

What to Look for in an Iron Supplement

Form

Iron supplements come in many forms such as tablets, liquid, or capsules. If you have difficulty swallowing tablets or capsules, liquid is a good alternative. However, slow-release tablets or capsules may be better tolerated and gentler on the stomach.

Type

There are many different types of oral iron. The most bioavailable type is ferrous iron which is most often recommended as ferrous sulfate, ferrous fumarate, and ferrous gluconate. 

Dosage

Always check with your physician before starting an iron supplement, and be sure to get a specific recommendation for the type of iron and dosage.

Why Trust Verywell Health

A personal note on my recommendations written above. As a dietitian, I am careful to recommend supplements. I spent time reviewing the most current clinical research on iron supplementation and optimal forms, looking at multiple products and brands, and consulting with trusted peers in dietetics. I believe the iron supplements in the round-up are made by trusted brands that are devoted to product purity and are composed of high-quality ingredients. — Eliza Savage, MS, RD, CDN

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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.
  1. Tolkien Z, Stecher L, Mander AP, Pereira DI, Powell JJ. Ferrous sulfate supplementation causes significant gastrointestinal side-effects in adults: a systematic review and meta-analysisPLoS One. 2015;10(2):e0117383. doi:10.1371/journal.pone.0117383

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