Are Iron Pills Made From Animals? Separating Heme From Non-Heme Sources

January 12, 2026 •

3 min read

While it's true that some iron supplements, known as heme iron, are derived from animal sources like bovine hemoglobin, the vast majority of widely available oral iron pills are not. These common over-the-counter options are made from non-heme iron, which is chemically synthesized from mineral salts, offering a vegan and vegetarian-friendly way to boost iron intake.

Quick Summary

The origin of iron supplements depends on the type. Heme iron supplements are animal-derived, while non-heme supplements, such as ferrous sulfate and ferrous gluconate, are synthesized from mineral compounds and are generally suitable for vegans.

Key Points

Not all iron pills are animal-based: Most common over-the-counter iron supplements contain non-heme iron, which is synthetically produced from mineral salts.
Heme iron is animal-derived: Specialized heme iron supplements are sourced from animal hemoglobin and are not suitable for vegans.
Manufacturing is chemical: Standard non-heme iron supplements like ferrous sulfate are created through chemical reactions involving iron and sulfuric acid, not animal products.
Vegan supplements are widely available: There is a large market of vegan iron supplements, but consumers must check for animal-based fillers and coatings.
Absorption differs by type: Heme iron is more readily absorbed, but non-heme options like ferrous bisglycinate may offer fewer gastrointestinal side effects.
Dietary intake is also important: Plant-based sources like lentils, spinach, and fortified cereals provide non-heme iron and can be part of a balanced iron strategy.

The Distinction Between Heme and Non-Heme Iron

To understand whether iron pills are made from animals, it's crucial to differentiate between the two primary types of iron found in food and supplements: heme and non-heme iron. Heme iron is only found in animal products like red meat, poultry, and fish, and is absorbed more efficiently by the body. Non-heme iron, on the other hand, is present in both plant-based foods and inorganic iron salts used for supplementation.

Heme Iron: The Animal-Derived Option

Heme iron is bound to hemoglobin and myoglobin, proteins found in animal tissue. Some specialized, and often more expensive, iron supplements are made from animal hemoglobin, particularly bovine (cow) sources. These are sometimes marketed for superior absorption but are not suitable for those following a vegan or vegetarian diet.

How it's made: Heme iron polypeptides are typically produced by enzymatically hydrolyzing bovine hemoglobin, breaking it down into smaller units that can be used in supplement form.
Who uses it: This type is typically sought by individuals with severe iron absorption issues or those who do not have a specific dietary preference against consuming animal products.

Non-Heme Iron: The Synthetic Standard

Most of the iron pills lining pharmacy shelves are non-heme iron supplements. These are not sourced from animals. Instead, they are chemically synthesized from mineral compounds. Common examples include ferrous sulfate, ferrous gluconate, and ferrous bisglycinate.

Ferrous Sulfate Manufacturing: As an example, ferrous sulfate is commonly produced by reacting iron with sulfuric acid or as a by-product of steel manufacturing. It is a simple chemical process involving non-animal ingredients.
Ferrous Gluconate Manufacturing: This supplement is the iron salt of gluconic acid, which is derived from glucose, a plant-based sugar. Again, no animal products are involved in creating the active iron ingredient.
Iron Bisglycinate Manufacturing: This chelated form of iron is made by combining iron with the amino acid glycine. While glycine can be sourced from animals, it is often synthetically produced for supplements, ensuring a vegan-friendly product.

Are All Vegan Iron Pills Created Equal?

Not all vegan iron supplements are the same. The type of non-heme iron used can affect bioavailability and side effects. For instance, ferrous bisglycinate is often marketed as being gentler on the stomach than ferrous sulfate, which is known for causing gastrointestinal issues like constipation. Other factors, like the inclusion of vitamin C to enhance absorption, also distinguish products from one another.

Comparison of Iron Supplement Types


Feature	Heme Iron Supplements	Non-Heme Iron Supplements (e.g., Ferrous Sulfate)
Origin	Animal-derived (e.g., bovine hemoglobin)	Synthesized from inorganic mineral salts
Vegan/Vegetarian	No	Yes (typically, but check for other animal-based fillers)
Bioavailability	High; absorbed 15-35%	Lower; absorbed 2-20%
Side Effects	Typically fewer gastrointestinal issues	Common gastrointestinal side effects, like constipation
Cost	Often more expensive	Generally more affordable and widely available

Beyond the Pill: Dietary Sources and Other Ingredients

For those seeking alternatives to supplements or concerned about the contents, a varied diet is a powerful tool. A wide array of plant-based foods offer non-heme iron, including lentils, spinach, chickpeas, and fortified cereals. Furthermore, always check the other ingredients on a supplement label. Some seemingly vegan iron supplements might contain animal-derived fillers or coatings, such as gelatin or shellac.

Conclusion: Making an Informed Choice

The assumption that all iron pills are made from animals is a common misconception. While animal-based heme iron supplements do exist, the most common and cost-effective iron pills are non-heme and derived from mineral sources, making them suitable for vegans and vegetarians. However, the key to making an informed choice lies in understanding the different types of iron, checking product labels for specific ingredients, and consulting a healthcare professional to determine the best course of action for your individual needs. By doing so, you can ensure your iron intake aligns with both your health and ethical considerations. For more information on iron deficiency, consult your doctor or reliable health authorities like the NIH Office of Dietary Supplements.

Frequently Asked Questions

Heme iron is found exclusively in animal sources and is more easily absorbed by the body. Non-heme iron is found in plant foods and most supplements, but has a lower absorption rate.

Not necessarily. While heme iron is more bioavailable, many people effectively supplement with non-heme iron. Absorption can also be enhanced by consuming non-heme iron with vitamin C.

Look for supplements that specify they contain non-heme iron forms like ferrous sulfate, ferrous gluconate, or iron bisglycinate. Also, check the 'other ingredients' list for animal-derived components like gelatin, bovine extract, or shellac.

Yes, common non-heme iron supplements, particularly ferrous sulfate, are known to cause gastrointestinal side effects such as constipation, diarrhea, and stomach upset.

Yes, some non-heme supplements like iron bisglycinate are marketed as being gentler on the stomach and better tolerated than ferrous sulfate.

The most common non-heme iron salts include ferrous sulfate, ferrous fumarate, and ferrous gluconate. Newer options include iron bisglycinate and ferric maltol.

Iron supplements are often recommended during pregnancy due to increased needs. However, it is crucial for pregnant women to consult their doctor to determine the correct dosage and suitable type of iron supplement.