How High of a Dosage Can You Go on Iron?

Most of the iron in your body is concentrated in your red blood cells. Iron is mainly responsible for carrying oxygen to your body's various cells and also has a role in the production of adenosine triphosphate, or ATP. In some cases, you may need to take iron supplements to ensure you are getting enough iron to meet your body's needs.

The dosage of iron supplements varies depending on age. (Image: Henrik Äijä/iStock/Getty Images)

Maximum Dose for Babies and Children

Babies and children up to 13 years of age should not take more than 40 mg per day, the Office of Dietary Supplements notes. This is the tolerable upper intake level, or the maximum dose of iron supplements that may be taken without suffering the side effects of excessive iron intake. However, tolerable upper intake level typically applies to babies and teens who do not have iron deficiency. The tolerable upper intake levels of babies and children with iron deficiency is usually between 4 to 6 mg/kg of body weight, according to MedlinePlus, a service of the National Institutes of Health.

Maximum Dose for Teens and Adults

Patients older than 13 should not take more than 45 mg of iron supplements daily, MedlinePlus explains. This tolerable upper intake level also applies to pregnant and breastfeeding mothers. Teenagers and adults with iron deficiency may be able to tolerate between 150 to 300 milligrams of iron daily. This range must be taken in three doses spread throughout the day.

Precautions and Interactions

Iron can impair the proper absorption of other medications, so you should take iron supplements either two hours before or two hours after taking other medication, the University of Maryland Medical Center notes. Medications used to lower cholesterol and those used to treat stomach problems may affect your ability to absorb iron. Birth control medications can increase your iron levels and may affect the maximum amount of iron supplements you can take.

Side Effects of Excessive Iron Intake

Taking more than the tolerable upper intake level can cause side effects such as muscle pain, backache and pain in your sides. Your hands and feet may feel numb or tingly as a result of too much iron in your body. You may also experience breathing difficulties and feel faint. Nausea and stomach cramps can also be a sign of too much iron. If you start exhibiting these symptoms, seek medical attention to avoid further complications.