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Feeling fatigued? Iron deficiency could be the culprit. Uncover the secrets of ferrous sulphate, the iron supplement that could get you back on track
Summary
1What are the uses of ferrous sulphate?
Ferrous sulphate tablets are mainly used to treat or prevent iron deficiency anaemia. Iron deficiency anaemia usually causes…
2Can you take folic acid and ferrous sulphate?
Folic acid is another common supplement recommended during pregnancy, and if you’re trying to conceive. The NHS says you can…
3Ferrous sulphate FAQs
Including “How much ferrous sulphate should I take?”, “How quickly does ferrous sulphate work?” and “How long should I take ferrous sulphate?”
Ferrous sulphate is a form of iron.1 Iron is an important mineral for human health because it helps your body to make red blood cells, and these carry oxygen around your body to keep your organs healthy and your body systems working well.2
Let’s take a look at ferrous sulphate in more depth so that you can understand what it is, why you might need it, how to take it and what you can expect.
What is ferrous sulphate?
Ferrous sulphate is a type of iron that is used as medicine to treat iron deficiency anaemia.3
Most people get enough iron through the foods that they eat, but some people are more likely to suffer from a lack of iron.4 Those at risk of lower iron include people born female, regular blood donors, athletes and those who can’t get enough iron through their diet (for example, if you have a poor diet or particular dietary restrictions).4-7
These people may benefit from using iron supplements to boost their levels.
What are the uses of ferrous sulphate?
Ferrous sulphate tablets are mainly used to treat or prevent iron deficiency anaemia.1 Iron deficiency anaemia usually causes a number of symptoms, including:6,8
- tiredness or a lack of energy
- shortness of breath
- heart palpitations/noticeable heartbeats
- skin that is paler than usual
- headaches
These symptoms may also be signs of other health conditions, so your doctor will carry out some medical assessments to check if you definitely have iron deficiency anaemia. These may include a full medical history, lifestyle questions and a blood test.8
If the doctor thinks you have low iron they may suggest ways you can increase your iron intake through your diet or taking iron supplements. If you’re diagnosed with this type of anaemia, you’ll probably be prescribed or advised to take ferrous sulphate tablets of a specific dosage according to your results.
Does ferrous sulphate have side effects?
Some people may experience unwanted side effects from taking ferrous sulphate.9
Some of the more common possible side effects of ferrous sulphate include:9
- feeling or being sick (nausea or vomiting)
- stomach discomfort or heartburn
- losing your appetite
- constipation
- diarrhoea
For most people, these complaints will be mild and there are often things you can do to help reduce or avoid them. For example, taking ferrous sulphate just after eating may help reduce any stomach troubles and boosting the fibre in your diet can ease constipation.9
However, if you take too much ferrous sulphate these side effects can be amplified and more serious. So always make sure to keep to your recommended ferrous sulphate dose as advised by your doctor or by following the supplement manufacturer’s guidelines.9
Can ferrous sulphate cause constipation?
Constipation is listed as a common side effect of taking ferrous sulphate.3,9
Exactly why constipation develops is unclear, but some researchers believe that it’s related to iron build-up in the digestive system causing water to move away from the lower intestines, causing stools (your poo) to become harder and constipation to occur.3
You can help to prevent the constipation that may occur by including more fibre in your diet by eating plenty of fresh fruit, vegetables, eating regular healthy balanced meals and drinking plenty of water.9
Regular exercise, such as daily walks, may also help to keep your bowel moving efficiently.9
How do you take ferrous sulphate?
Ferrous sulphate works best when it’s taken on an empty stomach, ideally around 30 minutes before eating or, if you forget, two hours after you last ate.1
You should also leave a two-hour gap before having tea, coffee, dairy products or eggs, because all of these are thought to stop your body from absorbing iron.1 However, as mentioned earlier, if you suffer from constipation or it upsets your stomach, you may want to try taking it with or after your food.1
Should you take ferrous sulphate during pregnancy?
If your doctor or midwife thinks that you may have low iron levels during pregnancy, you may be advised to take an iron supplement in the form of ferrous sulphate.10 These are safe to take in pregnancy, and in fact, it’s important that you have healthy iron levels so that you and your baby remain healthy.10 Just make sure you take the correct dose of iron as constipation is common in pregnancy, if you do experience this please speak to your doctor or pharmacist for advice.11
You can usually take ferrous sulphate while you’re breastfeeding too.10 When you take iron as a supplement, it doesn’t affect how much gets into your breast milk or how much reaches your baby.10
Can you take folic acid and ferrous sulphate together?
Folic acid is another common supplement recommended during pregnancy, and if you’re trying to conceive.10 The NHS says you can safely take folic acid while also taking ferrous sulphate supplements.10
Always speak to your doctor or midwife if you have any concerns about taking ferrous sulphate during or after pregnancy.
Check out our folic acid range here.
What are the best ferrous sulphate tablets?
Ferrous sulphate is available both in tablet and drop form. Tablets tend to be a more convenient option, as they are easy to carry and discreet to take.
Liquids are more bioavailable, meaning that your body can start using them immediately.12 But in the case of ferrous sulphate, there’s no need for an immediate dose of iron and instead, your doctor will be trying to raise and maintain your overall iron levels.8
Ferrous sulphate FAQs
How much ferrous sulphate you should take will depend on whether you’re taking it as a treatment as prescribed by your doctor or a preventative, and whether you’re taking it in tablet or drop form.13
If you’re worried about your iron levels, it’s best to have them checked by your doctor. If you’re actively trying to treat iron deficiency anaemia, then your doctor will provide you with a personalised ferrous sulphate dosage based on your specific needs.
Although you won’t feel the benefits of taking ferrous sulphate instantly, it won’t take too long to show its effects.
In most cases, people begin to feel better and see signs of improvement in iron deficiency symptoms after around three to four weeks. However, it may take up to two to four months to work fully.1
You can safely take ferrous sulphate for as long as you need to. How long you need to take it will depend on how low your iron levels are.
If you’re taking ferrous sulphate to prevent anaemia, you may need to take it for as long as you’re at risk of iron deficiency.13
For those taking ferrous sulphate to help resolve iron deficiency anaemia, you'll need to take it for several months. Your doctor will usually advise you to keep taking it for three to six months after your condition has improved to help build up your body's iron supply.12
The final say
Ferrous sulphate is a type of iron that your body absorbs relatively easily. It can be used to help to restore iron levels in people suffering from a deficiency.
Groups of people who are more susceptible to iron deficiency anaemia (including women who are menstruating, people who are pregnant and those with specific medical conditions) are likely to benefit most from ferrous sulphate supplements.4 However, for most other people, it’s possible to get the iron you need by including a variety of iron-rich food sources in your diet.
If you’re concerned about iron deficiency anaemia, or if you’re considering starting ferrous sulphate supplements, we strongly recommend you speak to your GP.
The advice in this article is for information only and should not replace medical care. Please check with your GP or healthcare professional before trying any supplements, treatments or remedies. Food supplements must not be used as a substitute for a varied and balanced diet and a healthy lifestyle.
- NHS. About ferrous sulfate [Internet]. [cited 2024 May 22] Available from: https://www.nhs.uk/medicines/ferrous-sulfate/about-ferrous-sulfate/
- American Red Cross. The importance of iron in your body [Internet]. [cited 2024 May 22] Available from: https://www.redcrossblood.org/local-homepage/news/article/iron-in-blood
- Parvataneni S, et al. Ileus due to iron pills: a case report and literature report on the importance of stool softeners. Cureus. 2020:12(6):e8392.Available from: https://doi.org/10.7759/cureus.8392. Accessed 27 May 2024
- NHS. Iron – vitamins and minerals [Internet]. [cited 2024 May 22] Available from: https://www.nhs.uk/conditions/vitamins-and-minerals/iron/
- NHS. Give blood – haemoglobin and iron [Internet]. [cited 2024 May 22] Available from: https://www.blood.co.uk/the-donation-process/further-information/haemoglobin-and-iron/
- Sims ST, et al. High prevalence of iron deficiency exhibited in internationally competitive, non-professional female endurance athletes – a case study. International Journal of Environmental Research and Public Health. 2022;19(24):16606. Available from: https://doi.org/10.3390/ijerph192416606
- Pawlak R, et al. Iron status of vegetarian adults: a review of literature. American Journal of Lifestyle Medicine. 2018;12(6):486–498. Available from: https://doi.org/10.1177/1559827616682933
- NHS. Iron deficiency anaemia [Internet]. [cited 2024 May 22] Available from: https://www.nhs.uk/conditions/iron-deficiency-anaemia/
- NHS. Side effects of ferrous sulfate [Internet]. [cited 2024 May 22] Available from: https://www.nhs.uk/medicines/ferrous-sulfate/side-effects-of-ferrous-sulfate/
- NHS. Pregnancy, breastfeeding and fertility while taking ferrous sulfate [Internet]. [cited 2024 May 22] Available from: https://www.nhs.uk/medicines/ferrous-sulfate/pregnancy-breastfeeding-and-fertility-while-taking-ferrous-sulfate/
- NHS. Common health problems in pregnancy. [Internet]. [cited 2024 Aug 12]. Available from: https://www.nhs.uk/pregnancy/related-conditions/common-symptoms/common-health-problems/
- NHS. How and when to take ferrous sulfate [Internet]. [cited 2024 May 22] Available from: https://www.nhs.uk/medicines/ferrous-sulfate/how-and-when-to-take-ferrous-sulfate/
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