Carbonyl Iron is essentially pure iron (98%) unlike most other irons which contain iron salts such as iron fumarate and iron gluconate. Traditional medicinal forms of iron, such as iron salts are poorly absorbed. Absorption is often less than 1% of the amount present, and the unabsorbed iron causes other problems such as constipation (especially in pregnancy), or less commonly looseness can result.

 

Unlike iron salts, elemental iron is virtually non-toxic. It is an essential trace element with a long history of safe use in foods and medicines.