Which Iron Supplement Does Not Cause Constipation?

Iron is a very important nutrient that we need for our bodies to function. Despite being so vital for our health, iron deficiency is one of the most common nutrient deficiencies across the world. This is because it is difficult for our bodies to absorb iron from food. 

Absorbing enough iron from your food is even more difficult than usual if you follow a vegetarian or vegan diet, or if you are pregnant or elderly. It is easy to boost your iron levels by taking an iron supplement.

Which Iron Supplement Does Not Cause Constipation?

You do not need a prescription to take an iron supplement, they are readily available from health stores. Iron supplements come in tablet form or liquid form and are available in different strengths. 

The problem with iron supplements is that many people experience unpleasant gastrointestinal side effects such as nausea or constipation. This can put people off and cause them to stop taking the supplement.

But why do iron supplements cause constipation? Are there any iron supplements you can take that don’t cause constipation? Keep reading to find out more. 

Why Do Iron Supplements Cause Constipation? 

Iron is very important for the production of energy, immune function, muscular performance, and thermoregulation. Iron is not produced within the body, so we have to get it from outside sources.

Sources of iron that come from animals are called heme-iron, and plant based iron sources are called non-heme iron. Heme-iron is easier to absorb into the system, whereas non-heme iron has to be converted into ferrous iron before it can be absorbed. 

The iron that is unable to be absorbed into the gut will feed the harmful bacteria in the gut. This can upset your stomach and cause issues like nausea and constipation.

Even iron from meat sources is not fully absorbed, which leaves some behind to be consumed by the bacteria.

Some less common side effects of taking iron supplements can include vomiting, diarrhea, abdominal pain and heartburn. There have been numerous studies into the link between constipation and iron pills.  

The uncomfortable side effects of iron supplements can cause some people to stop taking them, leading them to experience the alternative symptoms of an iron deficiency.

This can include fatigue, muscle weakness, reduced cognitive function, inefficient immune system, shortness of breath, heart palpitations, headaches, hair loss, fluctuations in body temperature, and poor concentration.

Some people with an iron deficiency are prone to fainting, and it can also cause pregnancy complications. 

The symptoms of iron deficiency are a lot more serious than the side effects of iron supplements. There are steps that you can take to reduce constipation – keep reading to find out how. 

How To Relieve Constipation

When you start taking iron supplements, you should start with half a dosage to let your body adjust. You can then move up to a full dosage. This should reduce the gastrointestinal side effects such as constipation or nausea. 

If you do experience constipation, there are some things that you can do to relieve the symptoms: 


Moving your body will help to speed up your metabolism and get your system going. Living a sedentary lifestyle is often a contributory factor to constipation 

Stay Hydrated

You need to drink plenty of water if you want to avoid being constipated. If you are dehydrated then your body will need to absorb more moisture from your food, making your stool more dry and solid and harder to pass. 

Eat More Fiber

Having a diet that is high in fiber will help to regulate your bowel movements. Try to eat whole grains and certain vegetables that contain high levels of fiber. 


Probiotics can help to improve the health of your gut and relieve constipation. You can get probiotic drinks from grocery stores, but they are not always very effective. Instead, try to eat fermented foods – sauerkraut, yogurt, kimchi, miso, tempeh etc. 

If you want to try and avoid experiencing constipation altogether, then there are certain supplements you should take. 

Which Iron Supplements Do Not Cause Constipation? 

If you want to try and avoid becoming constipated, these iron supplements are the best


Maltofer is an Australian brand of iron supplement that is taken in an oral form. It is available to buy online even if you don’t live in Australia.

It causes less gastrointestinal side effects than many other iron supplements which means that you are less likely to experience nausea or constipation.

Now Foods Iron Supplement

Now Foods offer lots of different types of vitamins and supplements, including an iron supplement. The tablets contain ferrous bisglycinate which is a type of iron recommended for people who are sensitive to gastrointestinal issues.

Solgar Gentle Iron

Solgar offers an iron supplement that is specifically designed to be more gentle on your stomach so that you can enjoy the benefits of higher iron levels without experiencing constipation.

Thorne Research Iron Bisglycinate

This iron supplement was designed for athletes as it is easy for the body to absorb. This means that their performance will not be negatively impacted by constipation or any other gastrointestinal side effects associated with iron supplements.

Spatone Liquid Iron Supplement

Spatone is an iron rich water based supplement that is designed to be suitable for the whole family. This means that it is gentle on the stomach and convenient to take. It doesn’t have as much iron as some of the stronger supplements, but is good for giving your iron levels a daily boost.

Active Iron

Active Iron is an award winning iron supplement that is designed to be absorbed effectively and to not cause constipation.

It comes in lots of different types – for men, for women, for pregnancy, for children, and special versions which also increase your energy levels or support your immune system.


Iron is a difficult nutrient for the body to absorb, which is why iron supplements can cause constipation. If you choose an iron supplement that is designed to be easily absorbed and gentle on the stomach then it should reduce the chances of constipation (if you find that you have stomach pain from your iron supplements, read here). 

Lindsey Morgan
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