Taking daily iron supplements can help manage iron deficiency anemia, though high doses can cause some side effects such as nausea, vomiting, diarrhea, constipation, and dark stools.

Iron is a mineral that produces red blood cells and helps carry oxygen around the body.

When your iron levels are low, it can lead to iron deficiency anemia, which decreases the flow of oxygen to your organs and tissues.

Iron deficiency anemia is one of the most common nutritional disorders in the world, affecting as many as 25 percent of people globally.

In this article, we’ll review the different types of iron supplements available and their dosage recommendations.

We’ll also look at the relationship between anemia and pregnancy, and explore some natural solutions that may help boost your iron levels.

Most people get all the iron they need from food. But when you have iron deficiency anemia, your levels are too low to meet your nutritional needs. You can try to get back up to typical iron levels through diet alone, but for most people with very low iron reserves, getting iron from food isn’t enough.

Iron supplements allow you to get the iron your body needs with an easy-to-take, high dose tablet or liquid. Iron supplements have more iron than you find in a multivitamin, and your doctor can monitor the dose you take.

If your body has difficulty absorbing iron from food, a supplement can help you get the dose you need of this essential nutrient.

Oral supplements

Oral iron supplements are the most common treatments for anemia. You can take them as a pill, a liquid, or as a salt.

You can find a variety of different types, including:

  • ferrous sulfate
  • ferrous gluconate
  • ferric citrate
  • ferric sulfate

Intravenous supplements

Certain people may need to take iron intravenously. You may need this method if:

  • your body cannot tolerate oral supplements
  • you experience chronic blood loss
  • your gastrointestinal (GI) tract has trouble absorbing iron

There are several different types available, including:

  • iron dextran
  • iron sucrose
  • ferric gluconate

High doses of oral iron supplements may lead to GI symptoms such as:

  • nausea
  • vomiting
  • diarrhea
  • constipation
  • dark stools

Intravenous iron can cause a hypersensitivity reaction (HSR). People may experience a mild, moderate, or severe HSR:

  • Mild HSR: itching, flushing, hives, heat sensation, slight chest tightness, hypertension, back pain, joint pain
  • Moderate HSR: cough, flushing, chest tightness, nausea, hives, shortness of breath, hypotension, rapid heart rate
  • Severe HSR: rapid symptom onset, eye swelling, wheezing, bluish skin, loss of consciousness, cardiac or respiratory arrest

If you experience an HSR during an iron infusion, your doctor may stop the treatment.

The dosage for iron supplements varies from person to person. Talk with a doctor about how much you need to take.

The doctor may recommend a daily dosing regimen. However, some research suggests taking iron once every other day may also be effective and has better absorption. Talk with the doctor about which dosing strategy is best for you.

Certain foods like dairy, eggs, spinach, whole grains, and caffeine can block iron absorption. Try to avoid having these foods at least 1 hour before and after you take your supplements. You should also take antacids and calcium supplements at least 1 hour apart from your iron.

If you have iron deficiency anemia, your doctor may recommend supplements at a much higher dose than the recommended daily allowance (RDA).

You can use the guidelines provided by the National Institutes of Health that show the RDA for most people. However, if your iron stores are low, eating just this amount may not be enough.


0–6 months0.27 mg
7–12 months11 mg
1–3 years7 mg
4–8 years10 mg
9–13 years8 mg


14–18 years15 mg
19–50 years18 mg
50+ years8 mg


14–18 years11 mg
19–50 years8 mg
50+ years8 mg

During Pregnancy

14–18 years27 mg
19–50 years27 mg

During Lactation

14–18 years10 mg
19–50 years9 mg

If you’re a vegetarian, the RDA is 1.8 times these amounts. That’s because plant-based sources of iron are harder for your body to absorb than meat sources.

If you’re living with mild iron deficiency anemia, it may be possible to treat your symptoms naturally through a nutrient-dense, balanced diet that includes iron-rich foods.

There are two main types of iron in your diet:

  • Heme iron is found in red meat, poultry, and seafood.
  • Non-heme iron is found in nuts, beans, vegetables, and whole grains.

Heme iron is easier for the body to absorb than non-heme, although both types can be part of a balanced diet. Some foods high in iron, such as spinach, also have components that make it hard for the body to absorb.

Vitamin C can help increase non-heme iron absorption. It’s a good idea to include items high in vitamin C in a plant-based meal.

Here are some iron-rich foods you can include in your diet:

FoodIron per serving
fortified breakfast cereals18 mg/serving
cooked Eastern oysters8 mg/3 oz
canned white beans8 mg/1 cup
dark chocolate7 mg/3 oz
pan-fried beef liver5 mg/3 oz
boiled and drained lentils3 mg/1/2 cup
boiled and drained spinach3 mg/1/2 cup
firm tofu3 mg/1/2 cup

During pregnancy, a person’s body needs much more iron to help supply oxygen to the baby. This extra demand increases the risk of developing iron deficiency anemia.

If left untreated, iron deficiency anemia can cause pregnancy complications like premature birth, low birth weight, and postpartum hemorrhage.

Some other factors that increase the risk of developing iron deficiency anemia during pregnancy can include:

  • being pregnant with multiple babies
  • having two closely spaced pregnancies
  • having frequent episodes of morning sickness

It can sometimes be hard for pregnant people to tell if they have iron deficiency anemia. Many of its common symptoms are similar to those of pregnancy. They can include:

  • weakness
  • fatigue
  • shortness of breath
  • dizziness
  • headache
  • pale skin
  • chest pain

The Centers for Disease Control and Prevention (CDC) suggests that pregnant people start taking a low dose oral iron supplement (around 30 mg per day) and get screened for iron deficiency anemia during their first prenatal visit.

They also encourage people with lab-confirmed anemia during pregnancy to increase their dosage to 60 to 120 mg per day. Pregnant people should talk with their doctor to determine their specific recommended dosage.

Most people will start to feel the benefit of an iron supplement within a few days.

According to the U.K.’s National Health Service (NHS), it takes about 1 week to feel better after starting a ferrous fumarate supplement.

However, it takes much longer to build up your iron reserves. That’s why many doctors recommend keeping up your iron supplementation for as long as 3 to 6 months if you have iron deficiency anemia, according to Australia’s National Blood Authority.

Can over-the-counter iron pills help anemia?

Over-the-counter iron pills, along with eating iron-rich foods, may help people with anemia caused by iron deficiency. However, it is important to discuss your recommended intake with a doctor. Sometimes, doctors may recommend a higher dosage for people with anemia due to iron deficiency. Other factors such as age, sex, the severity of the deficiency, and whether or not you’re pregnant can affect your recommended dose.

How long does it take to recover from anemia with iron supplements?

It can take about 1 week to start feeling better after beginning iron supplementation for iron deficiency anemia, according to the U.K.’s NHS. That being said, it can take longer to increase your iron reserves. It’s important to discuss dosage with a doctor to determine how long you should take supplements.

Is it OK to take an iron supplement every day?

Some doctors may recommend taking iron supplements daily. Research from 2017 suggests that taking iron supplements every other day may better help with absorption. If you have iron deficiency anemia, talk about dosage with your doctor to help ensure you get the amount of this essential nutrient that you need.

Iron is an essential mineral for maintaining good health. Iron supplements are an excellent way to prevent complications of iron deficiency anemia.

If you think you may have iron deficiency anemia, talk with your doctor about whether iron supplements are right for you.