The Health Benefits of 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. “Chelated” means that metallic ions are bonded to non-metallic ions to form a new molecule.

In theory, this process was designed to enable the iron to go through the digestive process without being broken down. Instead, the chelated iron gets carried into the cells—along with the amino acid that it is bound to—for more efficient absorption.

Possible Side Effects of Chelated Iron
Verywell / Emily Roberts 

Chelated iron is also said to lower the incidence of upset stomach commonly associated with taking iron supplements. But some experts disagree on whether the clinical research backs these claims, stating that regular iron (ferrous sulfate) works just as efficiently.

Chelated iron is known by many generic and brand names. Ferrous bisglycinate chelate is one of the most common generic names—commonly known as iron bisglycinate. Chelated iron is also known as, among many other names:

  • Bisglicinato ferroso quelato (IS)
  • Bis-glycino iron II (IS)
  • Bisglycino-iron (II) chelate (IS)
  • Eisen(II)-bisglycinat (IS)
  • Ferrous glycinate (IS)
  • Iron glycinate (IS)

Common chelated iron brand names include Gestafer (ferrous bisglycinate and folic acid) and Prenafer (ferrous bisglycinate and folic acid).

It’s important to note that chelated iron may not be potent enough to treat severe iron deficiency (particularly with anemia) but, it is useful in maintaining iron levels and preventing iron deficiencies from occurring in those who are high risk.

What Is Iron?

To understand what an iron supplement is, it’s important to learn about the basic function of iron and why it’s so vital to overall health. Iron is normally obtained by eating certain foods, such as red meat, liver (and other organ meats), spinach, and more. 

Iron is required by the human body for nearly every biochemical process. 

It’s found in almost every human cell and is considered an essential mineral because it is required to make the part of the red blood cells called hemoglobin. Hemoglobin is responsible for transporting vital oxygen throughout the body and to the brain, which has a very high need for oxygen.

Iron is involved in oxygen transportation, energy production, immune activity, hormone production, energy for muscles, and DNA.

Iron Deficiency Anemia

Iron deficiency is the most common nutritional deficiency in the world according to the World Health Organization (WHO).  Approximately 20% of the world’s population is reportedly iron deficient.

According to WHO, “Every age group is vulnerable. Iron deficiency impairs the cognitive development of children from infancy through adolescence. It damages immune mechanisms and is associated with increased morbidity [illness] rates.

"During pregnancy, iron deficiency is associated with multiple adverse outcomes for both mother and infant, including an increased risk of hemorrhage, sepsis, maternal mortality, perinatal mortality, and low birth weight.

"It is estimated that nearly all women are to some degree iron deficient, and that more than half of the pregnant women in developing countries suffer from anemia.”

The most prevalent symptom of anemia caused by iron deficiency is extreme fatigue. Other symptoms may include shortness of breath, brittle nails or vertical ridges on the nails, dry, damaged hair, headache, and dizziness.

In addition, an iron-deficient person may experience weakness, pale-colored skin, inflammation or soreness of the tongue and mouth, cold hands and feet, and/or chest pain or a fast pulse.

Health Benefits

The primary benefit of chelated iron is its ability to prevent low iron blood levels, preventing iron deficiency anemia in those who are at high risk.

People who commonly have low iron levels include infants who are breastfed or fed formula that is not sufficiently fortified with iron and children who may not eat an adequate diet with enough iron and need adequate iron due to rapid growth.

Others who may experience low iron levels include vegetarians because vegetables are lower in iron than meat, seniors who often have nutritional deficiencies due to health problems, depression, poverty, or inadequate access to healthy food, and athletes because of the need for more oxygen to work their muscles.

Women also need higher levels of iron than men, as well as people who are pregnant (due to the increased demand for iron during pregnancy). Those taking certain medications may also experience low iron levels (such as those taking oral contraceptives, aspirin, steroids, antacids, and anti-coagulants).

Research on Chelated vs. Non-Chelated Iron

A study involving pregnant women with iron deficiency, published by the Journal of Perinatal Medicine, discovered that there was no difference between the study participants who were given chelated iron (bisglycinate) and those given regular iron (ferrous sulfate).

This would indicate that the claims that chelated iron is absorbed better may not be true, and thus the more expensive price of chelated iron supplements (compared to regular iron) may not be justified. 

Another 2014 study showed that 30 milligrams of chelated iron taken for 90 days was just as effective as ferrous sulfate in maintaining normal iron levels in school-age children who had low iron levels (without anemia).

However, in a separate study comparing chelated iron to ferrous sulfate, those who took the amino acid chelate supplement reported significantly fewer side effects (including less stomach distress) than those who took the non-chelated ferrous sulfate. 

In an older study done on animals, chelated iron was found to cause fewer adverse effects than the use of other iron preparations. Ferrous sulfate (non-chelated iron) caused more intense symptoms of toxicity than equal doses of chelated iron. 

A 2013 study of preschool children discovered that both the ferrous sulfate (regular iron) group and the amino acid chelate (chelated iron) group showed equal adverse reactions, but, the chelated iron resulted in a higher increase in ferritin concentration.

Ferritin concentration is an indication of the iron concentration in the blood. However, the study also showed that hemoglobin levels did not change after the iron supplements were given.

Possible Side Effects

There are several minor side effects of taking iron, common adverse reactions may include:

Most of the minor side-effects of taking iron supplements will dissipate after the body adjusts to taking iron; if symptoms persist, it’s important to consult with your healthcare provider.

Serious side effects of taking chelated iron may include an allergic reaction (rarely), which may involve:

  • A rash
  • Itching
  • Swelling (particularly on the throat, tongue, or face)
  • Dizziness
  • Dyspnea (trouble breathing)

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


Accidental overdose of iron products (including chelated iron) is a leading cause of fatal poisoning in children. In part, this may be due to the fact that the dangers of taking too much iron are not common knowledge. 

If a child overdoses on iron, it’s important to call poison control and seek immediate medical attention.


Toxicity from overdose is perhaps one of the most dangerous side effects that can result from taking iron. Symptoms of iron overdose, according to Mayo Clinic may include fever, nausea, stomach cramps, sharp stomach pain, severe vomiting (may be bloody), and late symptoms of an iron overdose.

In addition, one may experience bluish-colored lips, fingernails, and palms of hands, pale skin, clammy skin, convulsions (seizures), shallow, rapid breathing, fatigue, and weakness (more severe than usual), and thready pulse (a pulse that is weak).

If symptoms of toxicity are noted when a person is taking iron supplements, emergency medical attention is required immediately.

Precautions and Contraindications

Chelated iron should not be taken unless otherwise ordered by the healthcare provider if a person suffers from iron overload disorder (such as hemochromatosis or hemosiderosis), alcohol addiction, liver conditions, and stomach or intestinal problems (such as ulcerative colitis, IBS, ulcers or other conditions).

For those taking ferrous bisglycinate, it’s important to note that this supplement also has folic acid.

Those with pernicious anemia (B12 deficiency) should make sure to speak with a doctor before taking chelated iron. The folic acid in the supplement could cause false lab tests. 

Iron supplements will pass into the breast milk—people who are breastfeeding infants should consult with the pediatrician before using iron. Iron use is considered safe during pregnancy, but only under the supervision of the prescribing healthcare provider.

Dosage and Preparation

As with all other supplements, always follow the instructions given by the prescribing healthcare provider on the dosage, safety, and precautions of chelated iron. If there is a discrepancy between what the package insert indicates and the prescribed dosage, consult with a pharmacist or the healthcare provider. 

General guidelines on dosage and preparation of chelated iron include that the average dose of iron for an adult with iron deficiency is between 60 to 120 mg per day for a minimum of 90 days (but always consult with the healthcare provider before deciding on which dose is right).

The “elemental iron” content of each type of iron supplement is perhaps one of the top considerations when choosing a type of iron supplement. Elemental iron refers to the exact amount of iron a supplement tablet or capsule contains.

The elemental iron content should be clearly listed in milligrams. Be sure that the elemental iron content is enough to equal the amount ordered by the prescribing healthcare provider.

Preparation of Iron

There are several important factors to keep in mind when taking an iron supplement, these include:

  • Take on an empty stomach if possible (this promotes the best absorption, but if nausea occurs, eating food with this medication may be recommended).
  • Avoid taking antacids, dairy products, or caffeinated beverages within two hours (before and after) taking chelated iron.
  • Drink an 8-ounce (240-milliliter) glass of water with iron supplements and avoid lying down for at least 10 minutes after taking iron.
  • Do not crush or chew the extended-release capsules or the chelated iron supplements (crushing or chewing will disable the effectiveness of the tablets/capsules and increase the risk of side effects).
  • Never take more iron than is prescribed by the healthcare provider. Keep in mind that iron can be toxic and can lead to serious health problems when too much is taken.

What to Look For

There are two different forms of iron, including “heme” which is available in meat (particularly in red meat) products, and “non-heme,” mainly available in plant foods. The amount of iron that is available to be absorbed in these two different types of iron varies significantly.

It’s not surprising that the absorption from heme (meat products) is quite higher than that of non-heme (vegetable products). This ability for various levels of absorbability is referred to as the bioavailability of a supplement. 

Other factors impact the bioavailability of iron, including things like foods eaten or other supplements taken with iron. Some substances lower and some raise the bioavailability of the iron supplement. For example, vitamin C is thought to increase the rate of absorption, so many iron supplements will also have vitamin C.

Iron needs to be in what is called the ferrous form to be absorbed properly in the body, be sure that a type of supplement purchased is a ferrous form of iron such as ferrous bisglycinate.

A Word From Verywell

Be careful not to confuse the terms 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. 

Frequently Asked Questions

  • Which is the most effective treatment for anemia—ferric iron or ferrous iron?

    Most research indicates ferrous iron in a slow-release formulation is the preferred treatment for iron deficiency anemia, as it's been shown to be highly bioavailable, effective, and easy to tolerate.

  • Do people with low iron levels always have anemia?

    No. Iron-deficiency anemia in adults is not diagnosed until levels of hemoglobin (the protein in blood that carries oxygen to the cells) reach certain thresholds: for adult men, a value of less than 13.5 grams per deciliter (gm/dl); for women, a value of less than 12.0 gm/dl.

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

    The clinical research data is mixed as to whether chelated iron supplements are more effective for preventing low hemoglobin levels. That said, several studies show chelated iron is just as effective as regular iron supplements and that chelated iron causes fewer side effects. 

9 Sources
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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Additional Reading

By 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.