Iron Supplements

Medically Reviewed on 9/28/2022

Generic Name: ferrous sulfate

Brand Names: Fer-In-Sol, Slow Fe, Feosol, Feratab

Drug Class: N/A

What are iron supplements (ferrous sulfate) used for?

Ferrous sulfate is used for the treatment and prevention of iron-deficiency anemias.

Iron supplements are available over-the-counter (OTC) in generic form. Other names for ferrous sulfate are the brand names Fer-In-Sol, Slow Fe, Feosol, Feratab, and many more.

What are the side effects of iron supplements?

The most common side effects associated with ferrous sulfate treatment are:

  1. constipation,
  2. dark stools,
  3. stomach pain,
  4. nausea, and
  5. vomiting.

Less common side effects include:

  1. diarrhea,
  2. heartburn, and
  3. urine discoloration.

What is the dosage for iron supplements?

The recommended dietary reference intake (RDA) based on elemental iron is:

  • Individuals 19-50 years : Males 8 mg/day, Females 18 mg/day,
  • Pregnant women: 27 mg/day,
  • Breastfeeding women: 9 mg/day.
  • Individuals = 50 years: 8 mg/day
  • For treatment of anemia, the recommended dose expressed as ferrous sulfate is 300 mg every 12 hours and may be increased to 300 mg every 6 hours (regular tablets) or 250 mg daily or every 12 hours (extended release tablets).
  • The dose for preventing iron deficiency anemia is 300 mg once daily of ferrous sulfate.

Iron supplements are available as preparations of:

  • Elixir: 220 mg/5 ml;
  • Solution 75 mg/ml;
  • Syrup: 300 mg/5 ml;
  • Tablets: 325 mg;
  • Delayed release tablets: 324, 325 mg;
  • Extended release tablets: 160, 142 mg.

Iron Supplements should be stored at room temperature, 15 C-30 C (59 F-86 F).


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Which drugs or supplements interact with iron supplements?

Are iron supplements safe to take if you are pregnant or breastfeeding?

  • Ferrous sulfate crosses the placenta and is safe to use during pregnancy. All pregnant females should be screened for iron deficiency anemia and treated as necessary.
  • Iron is normally found in breast milk. Ferrous sulfate is secreted into breast milk.


Ferrous sulfate (Fer-In-Sol, Slow Fe, Feosol, Feratab) is a supplement used for the treatment of iron deficiency anemias. The most common side effects associated with ferrous sulfate treatment are constipation, dark stools, stomach pain, nausea, and vomiting.

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Medically Reviewed on 9/28/2022
ferrous sulfate (Rx, OTC). Medscape.