Why does Iron typically cause constipation?

Cyto-Matrix MemberProducts, Scientific Research / Clinical Pearls

By Dr. Andrew Krause, ND CSCS CISSN

You probably know someone that has taken an iron supplement in their lifetime; you may have even taken one yourself. And what is the most common complaint?


It can get so bad that patients would rather not take an iron product at all rather than feel the effects of some products, which is one of the worst outcomes a healthcare practitioner can have as they are trying to help someone. It’s extremely frustrating to have picked the right ingredient at the right dose, only to have compliance be the limiting factor.

Thankfully, a new formulation of iron was developed that is able to virtually eliminate the side effect potential of taking an iron supplement, while reliably raising ferritin levels.

Iron Polysaccharide Complex is a non-ionic form of iron that is available as a liquid in Bio-Ferra™. It provides 100% elemental iron, which is a significantly higher percentage relative to other forms of iron on the market. (1)

Non-ionic iron is an important distinction to look for when choosing an iron, because the splitting into ions in the stomach is the main reason that patients will experience an upset stomach and constipation when taking typical iron supplements.

When there is an increase in the number of ions in the stomach, more water is drawn to the stomach (through ADH secretion) to dilute this elevated concentration of ions. In order to do this, water is pulled away from the lower gastrointestinal system, making stools harder, and more difficult to pass. (2)

By limiting this process altogether, constipation is virtually eliminated with BioFerra™. Bio-Ferra™ delivers the highest dose of elemental iron in a liquid product (20mg/teaspoon) in a palatable green apple flavour that makes compliance effortless, especially for children and the elderly.


1. Manoguerra AS, Erdman AR, Booze LL, Christianson G, Wax PM, Scharman EJ, et al. Iron ingestion: an evidence-based consensus guideline for out-of-hospital management. Clin Toxicol (Phila) 2005;43:553-70.

2. Oh MS. Evaluation of renal function, water, electrolytes, and acid-base balance. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 14.