What Is Chelated Iron?

A Common Supplement Used to Prevent Anemia

Chelated iron is a supplemental form of iron that has been chemically altered to allow it to pass through the digestive system without breaking apart.

When a compound is "chelated,” metallic ions are bonded to non-metallic ions to form a new molecule. Chelated iron is carried into your cells along with an amino acid bound to it. This bond allows for more efficient iron absorption.

This article will answer many of your questions about chelated iron supplements. We'll look at the potential uses of chelated iron and any side effects, precautions, and dosage for the supplement.

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement tested by a trusted third party, such as USP, ConsumerLabs, or NSF. 

However, even if supplements are third-party tested, that doesn’t mean they are safe for all or effective in general. Therefore, it is important to talk to your healthcare provider about any supplements you plan to take and check in about potential interactions with other supplements or medications.

Supplement Facts

  • Active Ingredient(s): Iron
  • Alternate Name(s): Iron bisglycinate, ferrous bisglycinate chelate, ferrous glycinate, iron glycinate
  • Legal Status: Legal and available over-the-counter (OTC).
  • Suggested Dose: Dosage varies, but the average dose of chelated iron for an adult with iron deficiency is between 60 and 120 milligrams (mg) per day.
  • Safety Considerations: Taking chelated iron may cause side effects, including upset stomach, diarrhea, constipation, and stomach cramps.

Uses of Chelated Iron

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

To better understand the uses of chelated iron, it’s important to review the basic functions of iron and why it’s so vital to your overall health.

Iron is found in almost every human cell and is considered an essential mineral because it is required to make hemoglobin. Hemoglobin is responsible for transporting vital oxygen throughout your body, including to your brain. Iron is also needed to make myoglobin, a protein similar to hemoglobin that carries oxygen to your muscles.

Iron is important throughout the entire life cycle. Infants need the mineral for normal growth and development, and older adults need iron to fight infections.

The primary use of chelated iron is to prevent iron deficiency anemia, a condition that can become serious if not treated.

Possible Side Effects of Chelated Iron
Verywell / Emily Roberts 

Iron Deficiency

The evidence supporting the use of chelated iron for iron deficiency is strong.

Iron deficiency is the most common nutritional deficiency in the world, according to the World Health Organization (WHO). Iron deficiency tends to affect pregnant people and children the most. In fact, 42% of children under 5 years old and 40% of pregnant people worldwide are deficient in iron.

Some people choose to use non-chelated iron to treat iron deficiency. Because of this, much of our research on chelated iron compares it to non-chelated iron.

In one such study from 2017, 150 pregnant people with iron deficiency anemia received either chelated or non-chelated iron supplements for 12 weeks. While both types of iron increased hemoglobin levels, those receiving chelated iron saw faster results. It was also reported to be better tolerated than the non-chelated form.

However, researchers who performed a different study on pregnant people with iron deficiency discovered no difference between the study participants who were given chelated iron as iron bisglycinate and those given non-chelated iron as ferrous sulfate.

Because iron deficiency is a concern in children, several studies have looked at the use of chelated iron in this population.

One study of children aged 1 to 13 years with iron deficiency anemia looked at how well either chelated or non-chelated iron worked in restoring iron levels. Once again, both forms of iron had positive results regarding hemoglobin levels in the study participants. However, chelated iron was more efficacious due to increased iron stores in the children who received it.

Another 2014 study showed that 30 milligrams of chelated iron taken for 90 days was just as effective as ferrous sulfate, a non-chelated iron supplement, in maintaining normal iron levels in school-age children with low iron levels.

However, iron deficiency can affect anyone. There are several possible causes of iron deficiency.

What Causes an Iron Deficiency?

Certain conditions and life stages can make you more likely to become iron deficient.

Common causes of iron deficiency include:

  • Excessive blood loss: This may be due to injury, surgery, internal bleeding, a heavy menstrual period, or the overuse of certain medications.
  • Inability to properly absorb iron: Certain genetic conditions may block iron absorption, as well as intense endurance sports and surgery.
  • Heart disease: Having heart disease can cause your body to be unable to use iron properly.
  • Kidney disease: People with kidney disease tend to make fewer red blood cells than normal.

Infants, young children, people with heavy menstrual cycles, and people who are pregnant are at a higher risk of becoming iron deficient. People with cancer or those with certain gastrointestinal disorders (like celiac disease or inflammatory bowel disease) may also become deficient in iron.

How Do I Know If I Have an Iron Deficiency?

The best way to know if you have an iron deficiency is to schedule a check-up with your healthcare provider.

There are many signs that you may have an iron deficiency. These include but are not limited to:

It's very important to treat an iron deficiency.

If left untreated, a deficiency in iron can lead to worsening symptoms and serious health consequences. In children, iron deficiency can lead to developmental delays. And in pregnant people, an untreated iron deficiency can cause complications during the pregnancy.

In most cases, iron deficiency can be treated with iron supplements, including chelated iron.

What Are the Side Effects of Chelated Iron?

You may be diagnosed with iron deficiency and instructed by your healthcare provider to take chelated iron. However, as with any supplement or medication, side effects are possible.

Side effects from taking chelated iron may be common or severe.

Common Side Effects

There are several potential side effects of taking iron. And most of these involve the gastrointestinal tract.

Common side effects associated with taking chelated iron include:

It is recommended that you let your healthcare provider know if you experience black, tarry stools, especially if they are accompanied by cramps or pain in your stomach.

Most of these side effects will dissipate after the body adjusts to taking iron. However, if symptoms persist, you should consult your healthcare provider.

Severe Side Effects

Serious side effects of taking chelated iron are rare.

An allergic reaction may occur when taking it for the first time. It's important to note, though, that cases of an allergic reaction from taking iron supplements have been reported with other forms of oral iron, not chelated iron.

However, an allergic reaction is still possible and may involve:

  • Rash
  • Itching
  • Swelling (particularly on the throat, tongue, or face)
  • Dizziness
  • Dyspnea (trouble breathing)
  • Low blood pressure (hypotension)

If you have any symptoms of an allergic reaction, seek immediate medical care.

Precautions

It's recommended only to take chelated iron when instructed to do so by a healthcare provider. This is because taking more iron than needed can cause side effects.

People with hereditary hemochromatosis, a condition that causes excessive iron absorption, should avoid taking iron supplements. Taking chelated iron or other iron supplements could cause iron overload in this population.

Many people with IBD, or inflammatory bowel disease, may think they cannot take iron supplements if they have an iron deficiency. However, a literature review from 2020 found that people with IBD can typically take oral iron without complications.

Iron use is considered safe during pregnancy and lactation but should be done under the supervision of the prescribing healthcare provider.

It is also considered safe for infants and young children to use chelated iron and other iron supplements. A healthcare provider can help you find the correct dose for your children.

Always talk to your healthcare provider before starting any new supplement to ensure it is safe to take.

Dosage: How Much Chelated Iron Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your needs.

When starting a new supplement, follow the dosage instructions on the label or as given by your healthcare provider. The dosage for chelated iron can vary and is often based on age, life stage, and whether certain conditions are present.

The dosage may also depend on what type of iron supplement you are taking.

You will most likely only be told to take iron supplements if you are deficient in iron. Typically, you can get enough iron through your diet or a multivitamin.

The average dose of elemental iron for an adult with iron deficiency anemia is 60 to 120 milligrams (mg) per day. But doses for anemia can start as low as 15 milligrams of iron per day.

You may also be instructed to take chelated iron supplements every other day rather than every day. Some research has shown that taking iron every other day could improve tolerance.

Chelated iron dosage may vary even more for children and people who are pregnant.

Infants diagnosed with iron deficiency may require 2 to 4 milligrams/kilogram (mg/kg) body weight of liquid iron drops per day. The iron dosage range for toddlers is 1 to 3 milligrams/kilogram daily.

Older children may tolerate 25 to 45 milligrams of iron per day for up to 90 days.

Iron supplementation guidelines vary during pregnancy. The Centers for Disease Control and Prevention (CDC) recommends that all pregnant people take a low dose of iron (30 milligrams per day) throughout the pregnancy. However, if anemia is present, it is recommended to take 60 to 120 milligrams of iron per day during pregnancy.

What Happens If I Take Too Much Chelated Iron?

Chelated iron can be toxic if too much is taken. It's also possible to overdose on iron supplements. Because of this, an upper limit (UL) has been put in place for iron.

For adults, the UL for all forms of iron is 45 milligrams. The UL is 40 milligrams for infants, toddlers, and children up to 14 years old. If the UL is reached in healthy people, side effects associated with taking chelated iron are more likely to occur.

Accidental overdose of iron products (including chelated iron) is a leading cause of fatal poisoning in children under the age of 6 years. When this occurs, it's vital to call poison control and seek medical care immediately. Iron overdose can lead to organ failure, coma, convulsion, or death in children and adults.

Taking more iron than directed can lead to iron toxicity. If your iron stores become full, free iron will begin circulating in your bloodstream. Iron in your bloodstream is toxic to your organs.

You must pay attention to how much iron you get through your diet and the chelated iron supplements you take. Having an iron-rich diet while taking iron supplements could lead to toxicity. This is why supplements are typically only recommended for people deficient in iron.

If you suspect an iron overdose or toxicity in a child, family member, or yourself, it’s important to seek immediate medical attention.

Interactions

Certain foods, nutrients, and medications can interact with chelated iron supplements. These interactions may cause drugs not to work correctly or cause poor iron absorption.

It is recommended to avoid the following foods two hours before and after taking chelated iron:

  • Milk
  • High-fiber foods (e.g., whole grains, raw vegetables)
  • Caffeinated beverages

You should also avoid taking calcium supplements or antacids within two hours of taking an iron supplement. Iron and calcium compete for absorption. This can lead to poor absorption of iron.

Iron can also interact with a few prescription medications. These include:

  • Levodopa-containing drugs such as Sinemet (carbidopa and levodopa) and Stalevo (carbidopa, levodopa, and entacapone): These medications are often used to treat Parkinson's disease and other conditions. Iron can reduce the absorption of levodopa if taken together. Separate taking levodopa/levodopa-containing medications and oral iron preparations by at least two hours.
  • Levothroid, Synthroid (levothyroxine): Taking iron at the same time as levothyroxine, a medication used to treat hypothyroidism, can lead to the drug not working effectively. Separate levothyroxine from oral iron preparations by at least four hours.
  • Proton pump inhibitors (e.g., Prevacid [lansoprazole], Prilosec [omeprazole]): These medications decrease stomach acidity and reduce iron absorption.

Carefully read the ingredient list and nutrition facts label of any supplement you take to know which ingredients and how much of each ingredient is included. Review the chelated iron supplement label with your healthcare provider to discuss any potential interactions with foods, other supplements, and medications.

How to Store Chelated Iron

It's important to take precautions in storing iron supplements. Improper storage could cause chelated iron supplements to go rancid or lose their potency.

The following are tips for storing chelated iron:

  • Keep the supplements in a cool, dry place out of direct sunlight.
  • If you have small children, keep chelated iron supplements out of their reach. Iron supplements can be toxic to small children if accidentally ingested.
  • Iron drops or liquid iron may not require refrigeration, but follow the storage instructions as listed on the supplement label.
  • Discard iron supplements after the expiration date listed on the packaging.

Similar Supplements

Many types of iron supplements may also be used to treat iron deficiency. Not all iron supplements are chelated, or attached to ions that allow the iron to pass through your digestive system without being broken down.

Iron supplements often come in the form of iron salts. Common forms of iron supplements include:

  • Ferrous sulfate
  • Ferrous gluconate
  • Ferric citrate
  • Ferric sulfate
  • Heme iron polypeptides
  • Carbonyl iron
  • Polysaccharide-iron complexes

Compared with these non-chelated forms, chelated iron is thought to be better for the digestive system since it passes through easier. However, gastrointestinal side effects are still possible when taking chelated iron.

Also, some studies have shown chelated iron supplements to be more effective than iron salts. But both forms have shown positive results in treating iron deficiency.

Frequently Asked Questions

  • Which form of iron is the most effective for treating iron deficiency anemia—ferric iron or ferrous iron?

    Ferrous iron is the preferred form of iron because it is highly bioavailable, effective, and easy to tolerate.

    Ferric iron has lower bioavailability than ferrous iron. According to one review, slow-release ferric iron preparations are usually poorly absorbed and appear to have no therapeutic advantage. They may cause fewer gastrointestinal side effects, but researchers suggest this is because the iron is carried past the proximal duodenum (where most iron is absorbed) into the distal gut.

  • Do people with low iron levels always have iron deficiency anemia?

    No. Iron-deficiency anemia in adults is not diagnosed until levels of hemoglobin (the protein attached to red blood cells that carry oxygen throughout your body) reach certain thresholds. Your healthcare provider may order blood tests including a complete blood count (CBC) test and other tests to evaluate levels of serum ferritin, iron, total iron-binding capacity, or transferrin.

    For adult males, a value of fewer than 13.5 grams per deciliter (gm/dl) of hemoglobin indicates iron deficiency anemia. For females, iron deficiency anemia is denoted by a hemoglobin value of fewer than 12 grams per deciliter.

  • Are chelated iron supplements worth the extra expense compared to non-chelated iron supplements?

    The clinical research data is mixed as to whether chelated iron supplements are more effective for preventing low hemoglobin levels.

    That said, some studies do show that chelated iron is just as effective as non-chelated iron supplements and chelated iron causes fewer side effects. 

Sources of Chelated Iron & What to Look For

Iron is available in many foods. However, chelated iron is only available in supplement form.

You can get all the iron your body needs through your diet. Iron supplements are only necessary in the case of an iron deficiency or a diagnosis of iron deficiency anemia.

Food Sources of Chelated Iron

While you cannot find chelated iron in food, you can find dietary iron in many foods.

Food sources of iron include:

  • Beef
  • Chicken
  • Turkey
  • Tuna, sardines, and oysters
  • Beans, lentils, and other legumes
  • Fortified breakfast cereals
  • Tofu
  • Spinach
  • Nuts
  • Eggs
  • Raisins

There are two forms of iron found in food. Heme iron is available in meats, and non-heme iron is found in plant-based foods. Heme iron is more readily absorbed in your digestive tract.

Vitamin C has been shown to increase the absorption of non-heme iron when both nutrients are consumed together. Foods containing vitamin C include citrus fruits, bell peppers, broccoli, tomato juice, cabbage, and potatoes. Pairing these foods with iron-rich foods may increase iron absorption.

Chelated Iron Supplements

You can find iron supplements in the form of capsules, tablets, chewable tablets, and drops.

Infants and small children typically use iron drops, as chewable tablets and capsules may be dangerous for them.

Some chelated iron supplements may include ingredients from animals and will not be suitable for vegans or vegetarians. Although, plant-based iron supplements are available for those wishing to avoid animal products.

Be sure to take chelated iron supplements as instructed. Taking iron on an empty stomach may increase absorption. But if doing so causes an upset stomach, then try taking chelated iron with a small snack.

Be careful not to confuse the term chelated iron with chelation therapy. Chelation therapy is the removal of extra iron in the body by administering a specific type of drug. Chelated iron adds iron for those who are iron deficient and chelation therapy removes excess iron from the body to prevent iron toxicity. 

Summary

Chelated iron is a supplemental form of iron that can be used to treat an iron deficiency.

Common side effects of chelated iron include upset stomach, stool changes, and nausea. Most people can get enough iron through their diet and should only take iron supplements if instructed by a healthcare provider.

If you think you have an iron deficiency, contact your healthcare provider to discuss whether chelated iron supplements may be right for you.

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Additional Reading

By Brittany Lubeck, RD
Brittany Lubeck, RD, is a nutrition writer and registered dietitian with a master's degree in clinical nutrition. 

Originally written by Sherry Christiansen
Sherry Christiansen
Sherry Christiansen is a medical writer with a healthcare background. She has worked in the hospital setting and collaborated on Alzheimer's research.
Learn about our editorial process