Ferrous Gluconate vs Ferrous Sulfate – Comparison of Uses & Side Effects

Ferrous Gluconate vs Ferrous Sulfate – Comparison of Uses & Side Effects:

Ferrous Gluconate (FG)

It is a type of iron that is absorbed in the stomach and small intestine and combines with apoferritin to form ferritin, which is stored in the spleen, liver, intestinal mucosa, and red bone marrow.

Ferritin is the main site of iron storage in the cell.

FG can be found under the following brand names – Ferate, Ferralet, Fergon, and Simron.


It is used to treat iron deficiency anemia.

As the name implies, iron deficiency anemia is caused by insufficient iron. Without sufficient iron levels, your body can’t produce sufficient hemoglobin in red blood cells which enables them to carry oxygen.

Taking this supplement helps the body to make more hemoglobin and so treat the anemia. 

Iron deficiency anemia symptoms include:

  • lightheadedness;
  • extreme fatigue;
  • cold hands and feet;
  • weakness;
  • brittle nails;
  • pale skin;
  • poor appetite, particularly in children and infants;
  • shortness of breath;
  • unusual cravings for non-nutritive substances;
  • inflammation or soreness of the tongue;
  • dizziness;
  • headaches;
  • fast heartbeat;
  • chest pain.


The usual recommended dose is 18 mg per day for women and 8 mg per day for men.

This supplement works best when given on an empty stomach. Also, try to take it half an hour before or 2 hours after food. Avoid taking antibiotics or antacids within 2 hours before or after taking this supplement.

Side Effects and Precautions

Common side effects may include:

  • loss of appetite;
  • diarrhea or constipation;
  • green-colored stools;
  • stomach pain;
  • temporary staining of the teeth;
  • vomiting;
  • nausea.

Rare side effects may include:

  • a fever;
  • bright red blood in the stools;
  • coughing up vomit that looks like coffee grounds;
  • pain in your throat or chest;
  • black or tarry stools;
  • stomach pain.

To make sure that this supplement is safe for you, tell your healthcare provider if you have ever had:

  • kidney disease;
  • ulcerative colitis;
  • liver disease;
  • if you are an alcoholic;
  • stomach problems;
  • if you receive regular blood transfusions;
  • iron overload syndrome;
  • thalassemia (a genetic disorder of red blood cells);
  • hemolytic anemia (a lack of red blood cells);
  • porphyria (a genetic enzyme disorder that causes symptoms affecting the skin or nervous system).

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There may be a negative interaction between this supplement and alcohol.

It is best to avoid consuming alcoholic beverages while taking this supplement.

Drug InteractionsPain medications drugs

It may negatively interact with other medications, especially with the following:

  • ofloxacin;
  • tetracycline (Brodspec, Sumycin, Panmycin, Tetracap);
  • norfloxacin (Noroxin);
  • minocycline;
  • jublia;
  • lomefloxacin (Maxaquin);
  • doxycycline (Adoxa, Oracea, Doryx, Vibramycin);
  • levofloxacin;
  • demeclocycline;
  • ciprofloxacin;
  • ofloxacin (Floxin).

Pregnancy & Breastfeeding      

It is not known exactly whether this iron supplement passes into breast milk or if it could negatively affect the infant. Tell your healthcare provider if you are breast-feeding a baby.

Also, it is not known precisely whether this supplement could be harmful to an unborn baby. Tell your healthcare professional if you are pregnant or plan to fall pregnant.

Ferrous Sulfate

It is an iron supplement that is used to treat or prevent low blood levels of iron.

This supplement can be found under the following brand names – Feosol, Fer-in-Sol, Fer-Gen-Sol, FeroSul, Feratab, Ferro-Bob, Ferra-TD, or Slow Fe.


It provides the iron required by the body to produce red blood cells.

This iron supplement is used to treat or prevent iron-deficiency anemia, a condition that occurs when the body has too few red blood cells because of poor diet, pregnancy, excess bleeding, or some medical problems.


The usual recommended dose is 100-200 mg orally divided every 12 hours.

Note – if it’s being used to treat anemia, you might notice an improvement after 3–4 weeks of treatment.

Due to the risk of tooth discoloration and mouth ulceration, tablets should not be chewed, sucked, or kept in the mouth. The supplement should be swallowed whole with water.

Side Effects and Precautions

Side effects may include:

  • dark stools;
  • constipation;
  • nausea;
  • diarrhea;
  • stomach pain;
  • vomiting;
  • urine discoloration;
  • superficial tooth discoloration.

Do not take this supplement if you:

  • have a disorder in which there is excessive absorption and storage of iron;
  • are receiving iron intravenously;
  • are receiving repeated blood transfusions;
  • are allergic to any of the other ingredients of this supplement.


There may be a negative interaction between this supplement and alcohol.

Drug Interactions

Tell your healthcare provider about all the medicines you use, particularly:

  • cimetidine (Tagamet);
  • acetohydroxamic acid (Lithostat);
  • etidronate (Didronel);
  • chloramphenicol;
  • levodopa (Dopar, Larodopa, Sinemet);
  • penicillamine (Cuprimine);
  • prolia;
  • methyldopa (Aldomet);
  • dimercaprol.

Furthermore, eggs, dairy products, tea, coffee, antacids, and spinach, can decrease iron absorption. You should take this supplement 2 hours after eating these foods.

Pregnancy & Breastfeeding

This supplement passes into breast milk. You should talk to your healthcare provider before taking it while breastfeeding a baby.

Also, it should only be used during pregnancy if it is clearly needed. You should talk to your healthcare professional about the risks of taking this medicine during pregnancy.

Ferrous Gluconate vs Ferrous Sulfate – Which Is Beter For Iron Deficiency Anemia?

Ferrous gluconate is an iron supplement that is used to treat iron-deficiency anemia, a disorder in which a lack of red blood cells results from too little iron in the body. It is one of the most common types of nutritional anemia worldwide.

Ferrous sulfate is an iron supplement that is used to treat iron-deficiency anemia.

The most commonly prescribed iron supplement by doctors for pregnant women is ferrous sulfate, which is cheap and reasonably well-absorbed.

But, according to a 2006 study that was done at the Klinicki centar Srbije, Nefroloska klinika, Beograd, ferrous gluconate was better absorbed and tolerated than ferrous sulfate.

This is probably because ferrous sulfate is formed by two inorganic substances, and their bonding is very strong and hard to break.


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1 thought on “Ferrous Gluconate vs Ferrous Sulfate – Comparison of Uses & Side Effects”

  1. Thanks for the info, I take ferrous Sulfate for Anaemia but find they are to powerful in a tablet [200mg] , they make my nose bleed.

    Anybody else with the same problem


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