Iron Supplements and Magnesium Peroxide: An Example of a Hazardous Combination in Self-Medication

Basic Clin Pharmacol Toxicol. 2016 Oct;119(4):412-7. doi: 10.1111/bcpt.12603. Epub 2016 May 4.


The use of self-medication, which includes dietary supplements and over-the-counter drugs, is still on the rise, while safety issues are not well addressed yet. This especially holds for combinations. For example, iron supplements and magnesium peroxide both produce adverse effects via the formation of reactive oxygen species (ROS). This prompted us to investigate the effect of the combination of three different iron supplements with magnesium peroxide on ROS formation. Hydroxyl radical formation by the three iron supplements either combined with magnesium peroxide or alone was determined by performing a deoxyribose assay. Free iron content of iron supplements was determined using ferrozine assay. To determine hydrogen peroxide formation by magnesium peroxide, a ferrous thiocyanate assay was performed. Finally, electron spin resonance spectroscopy (ESR) was performed to confirm the formation of hydroxyl radicals. Our results show that magnesium peroxide induces the formation of hydrogen peroxide. All three iron supplements induced the formation of the extremely reactive hydroxyl radical, although the amount of radicals formed by the different supplements differed. It was shown that combining iron supplements with magnesium peroxide increases radical formation. The formation of hydroxyl radicals after the combination was confirmed with ESR. All three iron supplements contained labile iron and induced the formation of hydroxyl radicals. Additionally, magnesium peroxide in water yields hydrogen peroxide, which is converted into hydroxyl radicals by iron. Hence, iron supplements and magnesium peroxide is a hazardous combination and exemplifies that more attention should be given to combinations of products used in self-medication.

Publication types

  • Comparative Study

MeSH terms

  • Antacids / adverse effects*
  • Antacids / chemistry
  • Deoxyribose / chemistry
  • Dietary Supplements / adverse effects*
  • Electron Spin Resonance Spectroscopy
  • Ferrous Compounds / adverse effects
  • Ferrous Compounds / chemistry
  • Food-Drug Interactions*
  • Humans
  • Hydrogen Peroxide / agonists
  • Hydrogen Peroxide / analysis
  • Hydrogen Peroxide / chemistry
  • Hydrogen-Ion Concentration
  • Hydroxyl Radical / agonists
  • Hydroxyl Radical / analysis
  • Hydroxyl Radical / chemistry
  • Iron, Dietary / adverse effects*
  • Lactates / adverse effects
  • Lactates / chemistry
  • Magnesium Compounds / adverse effects*
  • Magnesium Compounds / chemistry
  • Netherlands
  • Nonprescription Drugs / adverse effects
  • Osmolar Concentration
  • Peroxides / adverse effects*
  • Peroxides / chemistry
  • Reactive Oxygen Species / analysis
  • Reactive Oxygen Species / chemistry*
  • Self Care / adverse effects*
  • Self Medication / adverse effects


  • Antacids
  • Ferrous Compounds
  • Iron, Dietary
  • Lactates
  • Magnesium Compounds
  • Nonprescription Drugs
  • Peroxides
  • Reactive Oxygen Species
  • Hydroxyl Radical
  • ferrous sulfate
  • Deoxyribose
  • ferrous lactate
  • Hydrogen Peroxide
  • ferrous gluconate
  • magnesium peroxide