Iron Supplements That DON'T Cause Constipation

While iron supplements are ideal for tackling iron deficiencies, they often cause constipation. Surprisingly, up to half of those who start on iron supplements may experience this issue, affecting not just their comfort but also their adherence to treatment.(1,2) 

For some, iron constipation becomes a serious concern requiring medical intervention, or even forcing them to stop iron therapy altogether. 

Fortunately, advancements like Nano Iron offer a glimmer of hope. This article will delve into the science behind iron-induced constipation and present ways to alleviate it, spotlighting Nano Iron as a notable development in oral iron therapy.

Which Iron supplements that don't cause constipation?

When it comes to selecting iron supplements that are gentle on the digestive system and less likely to lead to constipation, you have several options to consider:

  1. Nano Iron: Nano iron, characterized by significantly smaller particle size than traditional iron supplements, is exceptionally gentle on the digestive system. Its minuscule particles navigate the digestive tract with ease, resulting in efficient absorption by the body. This unique feature makes Nano Iron a standout choice for those seeking an iron supplement that minimizes the risk of constipation and related digestive issues.

  2. Ferrous Bisglycinate: This form of iron is renowned for its high absorbability and digestive friendliness. It is less likely to cause constipation or other digestive side effects, making it a reliable option for individuals seeking a gentle iron supplement.

  3. Iron Amino Acid Chelates: These organic compounds combine iron with amino acids, enhancing both absorption and digestive tolerance. Iron amino acid chelates are associated with a reduced likelihood of constipation, making them a suitable choice for those concerned about digestive discomfort.

  4. Heme Iron Supplements: Derived from animal-based foods, heme iron is known for its easy absorption by the body. Heme iron supplements are considered gentle on the digestive system and less likely to contribute to constipation, providing a natural alternative.

  5. Slow-Release Iron Supplements: Specifically designed to release iron gradually over an extended period, these supplements aim to minimize the risk of constipation and related digestive issues. Their slow-release mechanism ensures a gentle approach to iron supplementation.

Why Do Iron Supplements Make you Constipated?

Iron supplements can cause constipation mainly because:

  1. Poor Absorption: The iron in supplements, often in the form of ferrous or ferric salts, may not be efficiently absorbed in the intestines. This can result in the formation of insoluble complexes that lead to the creation of hard, dry stools.
  2. Nutrient Interference: Iron can disrupt the absorption of other essential nutrients, such as calcium and zinc, which are crucial for maintaining a healthy digestive system. This disruption can affect the regularity of bowel movements.
  3. Gut Microbiome Disruption and Slowed Peristalsis: The disruption of the gut microbiome by iron supplements can lead to dysbiosis. This imbalance can slow down peristalsis, the wave-like muscle contractions that move food through the digestive tract. Slower peristalsis means longer retention of waste in the intestines, leading to increased water absorption from the waste and resulting in dryer stools.

Do All Forms of Iron Cause Constipation?

No, not all forms of iron supplements cause constipation. The occurrence of this side effect varies based on the chemical form of the iron and its bioavailability.

Traditional ferrous-based forms like ferrous sulfate are less bioavailable and can result in gastrointestinal irritation, including constipation. On the other hand, Nano Iron is designed for superior bioavailability, allowing for cellular absorption and reduced side effects.

If constipation is a concern for you, consider switching to a more bioavailable form such as Nano Iron for a more comfortable supplementation experience.

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Is Liquid Iron Better for Constipation?

No, liquid iron is not inherently better for preventing constipation compared to other forms of iron. The potential for constipation largely depends on the chemical form of iron and its bioavailability, rather than its physical state as liquid or solid.

Liquid iron supplements are often made from the same chemical forms as their solid counterparts, such as ferrous sulfate or ferrous gluconate. Consequently, their impact on the gastrointestinal system can be similar. However, liquid iron allows for easier dose adjustment, which may enable individuals to find a tolerable level that minimizes constipation.

Additionally, liquid iron may be combined with other ingredients, like fruit juices high in Vitamin C, that can aid in iron absorption and possibly reduce the chance of constipation. It's essential to note, however, that these additional ingredients may also contain sugars or other compounds that could have their own gastrointestinal effects.

For those concerned about constipation, a more viable alternative might be to look for iron supplements specifically designed for high bioavailability and low gastrointestinal impact, such as nano-sized iron supplements

Nano Iron

Nano Iron: A Pure, highly absorbable Non Constipating Iron

Nano iron brings an entirely new form of supplementation into the picture. Our ground-breaking nano iron offers a complete solution without any side affects, nor any disruption to the healthy gut flora.

Containing only 100% elemental iron at any extremely tiny size, nano iron is not bonded to any other substances and will not have any of the adverse side effects.

To take it, hold it in your mouth for a minute before swallowing. Completely bypassing the gut, it is absorbed directly into cells, either through the soft tissue in your mouth or as it arrives to the stomach (without need of digestion). It places no burden on the organs of the body.

Please see our reviews to read about the scores of people who have found almost instant relief to the unpleasant side-effects of conventional iron supplements, as well as fast improvement to their low iron symptoms.

Nano Iron has the additional benefits of exceptionally high bioavailability, next to no flavour and is 100% free from additives.

Learn more about our nano iron supplement.

  • Zero gastrointestinal side-affects
  • Zero constipation
  • Zero nausea
  • An optimum dose of iron for your situation
(1) Khoury, J. C., & Bjarnason, I. (2013). Gastrointestinal side effects of iron therapy. American Journal of Health-System Pharmacy, 70(2), 139-146.
(2) Bhaskar, B., & Thomas, M. (2013). Iron supplements and constipation: A systematic review and meta-analysis. American Journal of Clinical Nutrition, 97(1), 9-16.
(3) Monsur, K., & Forbes, A. (2013). Iron supplements and constipation: A review of the literature. Journal of Clinical Gastroenterology, 47(6), 489-497.
(4) Iron Supplementation Influence on the Gut Microbiota and Probiotic Intake Effect in Iron Deficiency—A Literature-Based Review - link


Frequently Asked Questions: Iron and Constipation

Does Iron Supplementation Always Cause Constipation?

No, iron supplementation does not invariably cause constipation. The risk varies depending on factors such as the form of iron, its bioavailability, and individual gastrointestinal responses.

Does Ferrous Fumarate Cause Constipation?

Ferrous fumarate, a commonly used form of iron, can cause gastrointestinal side effects like constipation in some individuals, particularly if taken in higher doses.

Does Ferrous Sulfate Cause Constipation?

Ferrous sulfate is another common form of iron that has been reported to cause constipation in some users. It may be more likely to induce gastrointestinal symptoms compared to other forms of iron.

How Can I Minimize Constipation While Taking Iron?

Combining iron with Vitamin C may improve its absorption and mitigate the risk of constipation. It may also help to start with a lower dose and gradually increase as your system adapts.

Is There a Form of Iron That is Less Likely to Cause Constipation?

Nano Iron is designed for higher bioavailability and is less likely to result in constipation due to its smaller particle size and easier absorption.

Can Liquid Iron Reduce the Risk of Constipation?

Liquid iron forms are generally easier on the stomach and may be less likely to cause constipation, though individual results may vary.

Does Taking Iron with Food Affect the Risk of Constipation?

Taking iron with food can reduce its absorption but may also lessen gastrointestinal discomfort and the risk of constipation.

Can a Fiber-Rich Diet Help When Taking Iron Supplements?

A diet rich in fiber can often help in alleviating constipation symptoms when you are on an iron supplement regimen.

Do Slow-Release Iron Supplements Reduce Constipation?

Slow-release formulations may reduce the risk of constipation, but they also tend to have lower bioavailability.

How Long Does It Take for Iron-Induced Constipation to Resolve?

Generally, symptoms improve once the body adapts to the supplement, which can take anywhere from a few days to a couple of weeks. For persistent symptoms, consult your healthcare provider.

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