How Much Iron To Take For Heavy Periods?

Menstruation or having monthly periods can play a significant part in the life of people assigned-female-at-birth (PAFAB). Spanning almost 40 years from puberty to menopause, periods cause a wide range of symptoms around the clock of your monthly cycle. 

You may find that these experiences are unpleasant and that your cycle and bleeding patterns change with the different seasons of life. It is normal for this to happen and people will have different occurrences regarding their period, for example, some bleed little or a lot and for a short or long period of time. Heavy periods can be particularly hard to manage, though there are a range of options out there, including iron supplements which can help.

Understanding heavy periods

How does it feel to have heavy periods?

Although it seems like a lot, about 60 ml of blood is lost during every period (this is close to 5-12 teaspoons).  Bleeding is also heavier on some days than others.

What makes a heavy period is sometimes unclear as what’s normal for one may be too much bleeding on a typical cycle for another. Some measure the heaviness of their period by how many sanitary products they go through in a day, although as this is a personal preference rather than strict rule, it may be an inaccurate measure. 

Generally however, a period is considered heavy if you:1

  • Need to frequently change your pad/tampon (every one-two hours)
  • Feel excessively tired or weak during menstruation so much that you are unable to do regular activities
  • Pass large clumps of blood during your period
  • Need to use two sanitary products together, for example, a pad and a tampon
  • Bleed enough to stain your clothes or bedding

Common causes of heavy periods

In almost half of cases of heavy period bleeding, there is no obvious or identifiable cause - simply explained as dysfunctional uterine bleeding

For young people starting their periods, the hormonal system is not mature enough and the cycles are not associated with egg release so this can lead to irregular cycles and even heavy bleeding. If it’s only occasional, there is nothing to worry about and in most cases, periods become “normal” on their own with time and without intervention.

If you’ve just been through childbirth or have reached menopause age, you may find that your normal bleeding pattern can change to a heavy flow.1,2

At the end of each menstrual cycle, the lining of the womb is shed along with blood, causing the period. This happens due to the contractions of the uterus but if uterine contractions are inadequate it can lead to heavy bleeding. This occurs due to things such as:1

In addition to this, any scar tissue in the womb, either from birth or as a result of surgery or endometriosis can cause profuse bleeding during periods. In endometriosis, a tissue similar to the lining of the womb is seen in abnormal locations like the ovaries. 

Infections in the womb or the pelvis can also cause heavy periods but they are usually associated with other symptoms like pain or discharge.3 

Occasionally, a heavy period can be caused by other medical conditions like hormonal disorders, clotting disorders like the Von Willebrand disease or heart, thyroid, kidneys or liver disorders.

Rarely, heavy bleeding can be caused by uterine or cervical cancer.


To help your doctor decide what treatment might be best for you, it is recommended to keep a record of:

  • The length of your the periods (days of bleeding)
  • The number of pads/tampons used (per day or total)
  • Any symptoms you experience and when (such as abdominal pain or mood swings)

If you develop heavy or prolonged bleeding, your doctor will perform blood tests and scans to look for causes. 

Treatments that might be recommended to you by your doctor include:

Iron deficiency in heavy periods

Chronic blood loss due to heavy menstrual bleeding can lead to depletion of iron stores that are not sufficiently replaced by dietary intake of iron alone. This leads to iron-deficiency anaemia - almost a third of the menstruating population suffer from this globally.4  Iron tablets will usually be prescribed if anaemia is detected in the blood tests. In severe cases, iron injections or even blood transfusion may be required.5

How much iron to take for heavy periods?

There are many types of iron preparations available like the ferrous sulphate, ferrous gluconate and ferrous fumarate that can be taken orally. They come in the form of tablets, capsules or syrup. Generally about 100-200 mg of elemental iron is prescribed daily for iron deficiency.  

Doctors usually recommend one tablet taken 1-3 times daily until up to 3 months after the iron depletion is restored, though your doctor will take into account your individual requirements. A blood test is performed after 2-4 weeks to check the response to iron intake. If no response is observed, a referral for specialist assessment may be required.

Best times to take iron tablets

To get the best results from your iron supplements you should aim to follow this rough guide:

  1. Iron intake is most effective when taken on an empty stomach, at least an hour before meals or two hours after meals
  2. Avoid tea, coffee, dairy products, soy milk or eggs for 2 hours after iron intake as these can interfere with iron absorption
  3. Take iron pills with vitamin C or orange juice as this helps with iron absorption
  4. Leave a gap to take other medicines as they may interfere with absorption of iron

If you happen to miss a dose, skip the dose and continue with other doses. Never take two tablets at the same time. People with iron deficiency anaemia generally regain their energy levels to some extent after one week of taking iron tablets. 

Sometimes taking oral iron can produce a lot of side effects like stomach ache, nausea, heartburn and constipation.  People who cannot tolerate iron because of these side effects, may be prescribed intravenous iron.

If someone takes an overdose of iron tablets, they could suffer from vomiting, stomach pain or diarrhoea. Serious cases of overdose, can cause vomiting of blood, bleeding from the bottom, having a fit or becoming unconscious. In such cases and even if you are not experiencing overdose symptoms,you should contact your doctor or out-of-hours medical service.  If you or a family member is experiencing any severe symptoms of an iron overdose you should call an ambulance or go to your nearest hospital A&E department.

Food for iron deficiency anaemia

If you are prone to iron deficiency due to having heavy bleeding you should focus on taking a diet rich in iron to prevent anaemia.

Good sources of iron include:

  • Liver (avoid during pregnancy)
  • Red meat
  • Beans such as red kidney beans, chickpeas
  • Nuts
  • Dried fruits
  • Dark-green leafy vegetables like watercress
  • Fortified breakfast cereals
  • Soybean flour

The Department of Health and Social Care (UK) advises that it is safe to take 17 mg or less of iron supplements daily if you feel that your menstrual blood loss is more than usual. You can move to a higher dose if your GP advises it. You may also consider taking daily supplementation of iron alongside folic acid, vitamin B12, vitamin C and other multivitamins which help support  red blood cell function in people with anaemia.


Monthly menstrual cycles can have a huge impact on your physical, mental, psychological and social well-being so understanding your period and what to do if it becomes a heavy period is important. A wide range of treatments is available for heavy periods depending on the cause. Heavy blood loss in periods eventually leads to iron-deficiency anaemia so taking iron supplements and consuming a balanced diet rich in iron-containing foods will help your body cope with heavy blood loss. If you are worried about your periods, don’t hesitate to contact your GP as they should be able to provide you with some reassurance and many possible solutions. 


  1. Heavy periods: Overview [Internet]. Institute for Quality and Efficiency in Health Care (IQWiG); 2017 [cited 2022 Oct 31]. Available from:
  2. Shapley M, Blagojevic M, Jordan K, Croft P. The spontaneous resolution of heavy menstrual bleeding in the perimenopausal years. BJOG [Internet]. 2012 Apr [cited 2022 Nov 1];119(5):545–53. Available from:
  3. Nuray Öksoz Kanbur, Orhan Derman, Tezer Kutluk, Aytemis Görgey. Coagulation disorders as the cause of menorrhagia in adolescents. International Journal of Adolescent Medicine and Health [Internet]. 2004 Apr 1 [cited 2022 Nov 2];16(2):183–6. Available from:
  4. Alleyne M, Horne MK, Miller JL. Individualized treatment for iron deficiency anemia in adults. Am J Med [Internet]. 2008 Nov [cited 2022 Nov 1];121(11):943–8. Available from:
  5. Jimenez K, Kulnigg-Dabsch S, Gasche C. Management of iron deficiency anemia. Gastroenterol Hepatol (N Y) [Internet]. 2015 Apr [cited 2022 Nov 1];11(4):241–50. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Keerthi Ganesh

M.B.B.S, Medicine, Coimbatore Medical College, India

Dr Keerthi Ganesh is a medical doctor working in Leicester. She has broad clinical knowledge and experience achieved through working in both primary and tertiary care settings since 2004.She has trained in Family Medicine and diabetology.
She has a keen interest in writing to simplify medicine for the general public. She has been associated with Klarity since September 2022. She is also a responsible mother of two children and believes that pursuing hobbies and passions is key to promoting wellbeing among doctors. presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
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