Ferrous sulphate is a form of iron supplement often used to replenish iron stores and support the unwelcome symptoms of an iron-deficiency.
But how do ferrous sulphate tablets work? When can they help? And what is the best way to get the benefits from supplementary iron?
Iron is a mineral. Its primary purpose is to make haemoglobin, a protein in red blood cells that transports oxygen around your body.
There are many sources and varieties of iron. They broadly fall into two main groups: ferric or ferrous. Ferrous sulphate is a form of ferrous iron. Others include ferrous fumarate and ferrous gluconate.
In its natural form, iron sulphate is a crystal. But due to being widely used as an iron supplement, you’ll usually find it in the form of tablets and droplets.
In short, ferrous sulphate is one kind of iron sulphate. You may also see it called ferrous sulfate or iron sulfate.
It’s surprisingly common for people to be deficient in iron.
Ferrous sulphate is a dietary supplement that can boost your iron levels if you’re showing signs of a deficiency. As a result, it’s often used in the prevention and treatment of iron -deficiency anaemia.1
Most people get the iron they need from their diet. But taking an iron supplement, such as iron sulphate tablets, can be helpful if you’re finding it difficult to get the levels you need from food alone or are prone to low levels of iron.
If you’re iron deficient, you might feel tired, lightheaded, or weak.
Four groups that can be more at risk of an iron deficiency include:2
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The recommended daily iron intake increases to 27mg when you’re expecting a baby (compared to the standard 18mg for most adult women under 50).2
This is because the female body has to work overtime to supply blood and oxygen to the growing foetus. To manage this, the amount of blood in a woman’s body increases by nearly 50% during pregnancy.3
However, this increased demand means many pregnant women find themselves short of red blood cells. This increases their risk of anaemia.
If you’re pregnant and suspect you have an iron deficiency, the best course of action is to visit your doctor who can confirm this with a blood test. They may then suggest taking an iron sulphate supplement to build up your stores of this essential mineral.
The simple answer is yes. But that doesn’t mean you should rush out to stock up on some kind of iron sulphate formula as soon as you get a positive pregnancy test.1
You only need to take ferrous sulphate in pregnancy under the advice of a medical practitioner and if you’re diagnosed with a deficiency.
This is because not every mum-to-be will need to take iron supplements. In reality, many women can get enough from food, combined with the extra iron in a multivitamin pregnancy supplement.
Like iron, folic acid is an important nutrient for pregnant women. In fact, it’s recommended that women who are trying to conceive or are pregnant take folic acid until they’re 12 weeks pregnant.4
But can you combine these two mineral supplements? According to the NHS, you can safely take folic acid while also taking a ferrous sulphate supplement.4
How you take iron supplements, like ferrous sulphate, can make them more effective. Here are a few general rules:
Your ferrous sulphate dose depends on whether you’re taking it to prevent iron-deficiency anaemia or to treat it.
|To prevent anaemia||To treat anaemia|
|Iron sulphate tablets||Dose: one 200mg tablet||Dose: one 200mg tablet|
|Iron sulphate drops||Dose: 2.4ml - 4.8ml||Dose: 4ml|
|Frequency: once a day||Frequency: once/twice a day|
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 see signs of improvement in iron deficiency symptoms after around 1 week. The full effects are likely to be felt within 4 weeks of taking the supplement.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.
Some people may experience unwanted side effects from taking ferrous sulphate.
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 iron just after eating can help reduce any stomach troubles and boosting the fibre in your diet can ease constipation.
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 discussed above, constipation can be an unwanted side effect of taking a ferrous sulphate supplement.
Unabsorbed iron in your body can feed pathogenic bacteria in your gut, which causes changes in your microbiome and can lead to effects like constipation.⁵
Generally improving your gut health could help to reduce this, though it likely won’t stop it altogether. Drink plenty of water and see if you can include some gut-friendly bacteria into your diet with high-fibre and fermented foods.
If you’re struggling with constipation while taking ferrous sulphate, try changing up the time you take it. It’s recommended you take it on an empty stomach, but if your gut is particularly sensitive, it might help to take your iron sulphate supplement directly after a meal.
You might also find that a stool softener provides some relief.
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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 menstruating women, pregnant females and adolescents) are likely to benefit most from ferrous sulphate supplements.
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.
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.
Before taking any supplements or minerals, it’s best to make sure you’re getting all the nutrients through your diet first.
Food supplements must not be used as a substitute for a varied and balanced diet and a healthy lifestyle.
Last updated: 9 September 2022
Last updated: 15 April 2021
Joined Holland & Barrett: Jan 2018
Bsc in Nutrition, Registered Associate Nutritionist and Certification in Pre and Post Natal Nutrition
Donia started her career as a freelance nutritionist, later she joined Nestle as their Market Nutritionist to help support their healthier product range, before joining the team at Holland & Barrett in January 2018.
Donia has over 6 years experience as a Nutritionist and also works with clients on a one to one basis to support their goals which include weight loss, prenatal and postnatal nutrition and children’s health.