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Iron Info for Frequent Donors

Iron and Blood Donation

Donating a unit of whole blood or double red cells (2 units) removes iron from your body. You need iron to make new red blood cells. Losing iron through blood donation may affect your health.

The American Red Cross now recommends that individuals who give blood on a regular basis should take a multivitamin with iron or an iron supplement to replace the iron lost with blood donation.


Am I a frequent blood donor?

If you fall into one of the following groups then you are considered a frequent blood donor:

  • Women 16 to 50- years-old who donate 2 or more units a year
  • Women older than 50 who donate 3 or more units a year
  • Men who donate 3 or more units a year

Note: A whole blood donation is one unit of blood; a double red cell donation is 2 units of blood. For example, a man who gives 2 double red cell donations (4 units) a year is a frequent blood donor.

I am a frequent blood donor – what can I do to maintain my iron level?

  • Eat a healthy balanced diet containing iron rich foods
  • Take a multivitamin with iron in it or an iron supplement to replace the iron lost with blood donation
  • Discuss your iron level, how much you donate blood, and if you need to take an iron supplement with your doctor.

How much iron do I lose if I donate 1-unit of blood?

You lose about 220-250 mg of iron when you donate a unit of blood. A double red cell donation contains about twice as much (about 470 mg of iron). It can take 8 weeks or more for your body to replace the iron lost with blood donation, even with an iron-rich diet.

If I was allowed to give blood today, does that mean that I have enough iron?

Even if you qualify for blood donation, you may have low iron levels.

Why isn’t a good diet enough?

Eating a well-balanced diet is important for everyone, but simply eating iron-rich foods may not replace all the iron lost with blood donation.

How might low iron levels affect me?

Many people with low iron levels feel fine and have no symptoms, but low iron levels may cause:
  • Anemia
  • Tiredness and irritability
  • Reduced endurance during exercise or everyday activities
  • Difficulty concentrating
  • Pica, (a craving to chew things such as ice or chalk)

Should frequent blood donors replace the iron they lose with each blood donation?

Yes, the Red Cross now recommends that frequent blood donors should take a multivitamin with iron in it or an iron supplement to replace the iron lost with each blood donation. If you choose to take iron replacement therapy, you should discuss the options with your physician.

Where can I get iron supplements?

Iron is available as an over-the-counter medicine at drug stores, health food stores and grocery stores without a prescription, as well as through the internet. Prices and doses vary greatly.

What kind of iron supplement should I take?

Iron supplements come in different formulations, with different characteristics. Some examples are ferrous sulphate, ferrous gluconate, ferrous fumarate, or carbonyl iron. These formulations contain different amounts of iron and it is important to look at the amount of “elemental iron” available for absorption.

How much iron should I take?

Current recommendations range from 19 mg (the amount of iron in a typical multivitamin with iron) to 45 mg (the amount in elemental iron caplets) for 6 weeks to 3 months.  Follow all directions on the product package, or take as directed by your doctor or pharmacist.

Do not take more than the recommended dosage because higher doses may be harmful. If you are uncertain about any of the information, consult your doctor or pharmacist.

Lower doses are associated with few or no side effects but take a longer period of time to achieve full iron replacement. The length of time you should take iron after each blood donation depends on the amount of elemental iron in each dose.

Here are some examples of different strategies for the dose of iron and the amount of time needed for iron replacement:

9 mg     (every day for 32 weeks)
18 mg     (every day for 16 weeks)
27 mg     (every day for 10 weeks)
38 mg     (every day for 8 weeks)

Why doesn't a single dose of iron replace what I lose from blood donation?

There is a limit to how much iron your body can absorb each day (about 2-4 mg/day). The goal is to replace the iron lost from blood donation over 6 weeks to 3 months. Taking larger doses of iron for a shorter period of time may not replace the iron you need - and could result in more side effects.

Will I have side effects from taking iron?

Iron supplements may cause side effects, which are described on the product package. Side effects may include symptoms like constipation, diarrhea, or upset stomach. If the symptoms are bothersome, you may need to take a lower dose over a longer period of time, or take the iron supplement with food. Discuss any side effects or alternatives with your doctor or pharmacist.

Can iron supplements be harmful?

Accidental ingestion of iron by children can result in their death. Keep all iron-containing products out of the reach of children. Individually-packaged pills and childproof bottles may prevent poisoning. In case of suspected ingestion, call an emergency room or poison control center immediately.

Iron supplements may be harmful to people with iron overload syndromes, such as hereditary hemachromatosis. If you have been diagnosed with iron overload or hereditary hemachromatosis, or you know someone in your family with the condition, please discuss iron balance with your physician. The American Red Cross does not currently accept as blood donors those individuals who are being treated for iron overload by a physician.