The most common reason people take iron supplements for supporting the treatment of iron deficiency and the resulting, anemia. If iron levels are low, then the red blood cells cannot carry enough oxygen to the body, and this often leaves people feeling very tired.

Iron is essential in red blood cells as it helps deliver oxygen from the lungs to cells all over the body. Once the oxygen is delivered, iron then helps red blood cells carry carbon dioxide waste back to the lungs to be exhaled.

Women frequently take iron supplements to make up for iron lost in heavy menstrual periods, but they can also eat iron-rich foods, such as pork, ham, chicken, fish, beans, and especially beef, liver, and lamb to support iron levels. Iron is also used for improving athletic performance, as it supports the carriage of oxygen throughout the body, treating attention deficit-hyperactivity disorder (ADHD), canker sores. and some people also use iron for Crohn's disease, depression, fatigue, and the inability to get pregnant.