If you are considering heme iron supplements, this guide is for you. Using easy-to-understand language and terms, we will take you through all you need to know.

We will answer all your questions, including the following:

  • What is heme iron?
  • What are the main dietary sources of heme iron?
  • What are the different types of iron supplements?
  • How much heme iron do I need?
  • What are the best types of iron supplements?

Let’s get started by looking at what heme iron is and why it’s such an important mineral.

What is Heme Iron?

Iron is an essential mineral and plays a vital role in the body. It’s used to make red blood cells, which carry oxygen around the body, and it also contributes to normal cognitive function, normal energy metabolism and the normal formation of red blood cells.

There are two different types of iron: heme and non-heme iron. Heme iron mainly comes from animal sources. Red meat, offal, poultry and fish are all excellent sources of iron.

Non-heme iron comes from plant-based sources. These include fortified cereals and breads, rice, oats, nuts, beans and leafy greens. And best of all, dark chocolate is also rich in non-heme iron.

Heme iron is more easily absorbed by the body than non-heme iron. Therefore, vegetarians have to eat twice as much iron as meat-eaters to get the same amount.

Sources of Heme Iron

As we have seen, the main source of heme iron is meat. This is because meat has many blood proteins and hemoglobin, which help the body transport oxygen.

If you want to increase the amount of heme iron in your diet, here are the best foods to include.

  • Organ meats: Kidneys, liver, brain and heart are incredibly nutritious and score highly for heme iron. The liver, in particular, is one of the most nutrient-dense organ meats and contains plenty of heme iron.
  • Red meat: Often given bad press, red meat is, however, packed full of protein and essential vitamins and minerals, including iron. When it comes to heme iron, all red meats pack a punch. Including lots of steaks, chops and mince in your diet will increase your heme iron intake.
  • Poultry: Although not as iron-rich as red meat, chicken and turkey are nevertheless good sources of heme iron.
  • Fish and shellfish: Other excellent choices rich in heme iron include fish and shellfish. Canned varieties of fish, especially sardines and tuna, are excellent choices. And clams, oysters and mussels will also deliver a healthy dose of heme iron.

Most people get enough heme iron from their diet. However, others find it difficult to get sufficient iron from food alone. These people may choose to increase their intake of iron supplements.

The Different Types of Iron Supplements

There are several different types of iron supplements available. These include:

  • Ferrous sulfate
  • Ferrous gluconate
  • Ferric citrate
  • Ferric sulfate

Usually available as tablets and capsules, these iron supplements also come as salts or liquids.

However, different types of iron supplements contain varying amounts of elemental iron. Most iron supplements contain non-heme iron.

Heme vs Non-Heme Iron

When it comes to heme vs non-heme iron, the main difference is the body’s rate of iron absorption. Heme iron is absorbed at a much higher rate than non-heme iron. It’s estimated that the body absorbs only 2-20% of non-heme iron. In comparison, heme iron has a 15-35% absorption rate.

Non-heme-based iron supplements are also more likely to result in side effects. Indigestion, stomach upset, flatulence, constipation and diarrhea are common complaints associated with some types of iron supplements.

While iron is essential to your overall health, some problems are associated with overdoing your intake of heme iron. Dramatically increasing the amount of heme iron in your diet can lead to inflammation, as well as causing damage to gut cells due to the production of hydroxyl, a free radical.

Your body finds it much easier to regulate iron absorption from plant-based foods, meaning that although heme iron is more easily absorbed, the body is not so good at regulating this process. As a result, it’s important to find the right balance of heme vs non-heme iron.

Are They Absorbed Differently?

Just as there’s a difference in how the body absorbs heme and non-heme iron, absorption of iron supplements also varies.  A lot depends on how and when you take your iron supplements.

Vitamin C is known to help with iron absorption, and some supplements must be taken with a glass of orange juice to maximize their performance. To get the best absorption, other iron supplements need to be taken alongside food. Even with these measures, lots of people still experience the unwanted side effects of nausea or an upset stomach. By contrast, Active Iron has twice the absorption compared to standard ferrous sulphate supplements, and its gentle formula means you can take it on an empty stomach.

Liquid iron supplements are often proposed as an alternative for those who experience side effects such as constipation or nausea. It’s suggested the liquid format is gentler on the stomach and easier for the body to absorb. However, manufacturers tend to make liquid iron supplements with low potency, as a safety precaution in case a child accidentally drank the liquid iron, which could cause serious health complications.

Furthermore, some foods are known to affect your body’s ability to absorb iron. Health care professionals usually advise avoiding taking iron supplements with tea, coffee, milk and dairy products. Wholegrain cereals with high levels of phytic acid are also best avoided.

How Much Heme Iron Do You Need?

 How much iron you need depends on your sex, age and lifestyle. Generally, women need more iron than men due to menstruation, pregnancy and breastfeeding.

The EU uses a system called Nutrient Reference Value (NRV), which sets out the average daily amount of vitamins and minerals needed for good health. The NRV for iron is currently 14mg.

The US Department of Health has set out the following recommended daily allowance (RDA) for males and females depending on age.

Age Male Female Pregnancy Breastfeeding
1-3 years 7 mg 7 mg
4-8 years 10 mg 10 mg
9-13 years 8 mg 8 mg
14-18 years 11 mg 15 mg 27 mg 10 mg
19-50 years 8 mg 18 mg 27 mg 9 mg
51+ years 8 mg 8 mg

The RDA covers iron from all sources, heme and non-heme, plus any iron supplements.

Vegetarians and vegans need to eat twice as much iron in their diet as meat-eaters to achieve their RDA. Heme iron from meat and heme iron supplements is more easily absorbed by the body.

Furthermore, if you are an active athlete, then you may need more iron in your diet, as the body’s muscles use iron to make energy. If you participate in endurance sports such as running, rowing and cycling, increasing your iron intake may enhance your overall performance. Iron helps by transporting oxygen to tired muscles more efficiently.

The Best Types of Iron Supplements

 So, what are the best types of iron supplements?

When selecting the right supplement for you, the main things to consider are:

  • iron absorption
  • potential side effect

When selecting an iron supplement, it is important to focus on one which provides the maximum amount of absorption of iron, while also minimizing the side effects.

Active Iron is a superior choice to other iron supplements. Being both kind and gentle to the stomach, Active Iron increases the amount of iron absorbed by targeting the body’s natural site of iron absorption, in the intestine. In fact, Active Iron is clinically proven to have 2X better absorption compared to standard ferrous sulfate iron supplements.*

The ground-breaking technology in Active Iron protects the iron with a special whey layer allowing it to bypass the stomach, where most iron supplements are broken down and oxidized. This means whatever your needs, you will be getting the maximum amount of iron with the satisfaction of reduced side effects.

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For Athletes

Active exercisers often find they need additional iron in their diets, and they can top up their iron intake during periods of sustained and heavy training with supplements. Intense exercise can put your body under stress, affecting your ability to absorb iron, leading to an ever-increased need.

Active Iron is the answer for many athletes. Active Iron Advance is Certified by the Informed-Sport programme, so athletes can be confident that Active Iron is free from prohibited sports substances.

The unique formulation Active Iron will help increase iron absorption, which in turn helps you give your best performance.



Many vegetarians, particularly women with periods, find it hard to get enough iron from food sources alone. As we have seen, plant-based non-heme iron is less easily absorbed by the body. However, for ethical reasons, many vegetarians do not want to take heme iron supplements, as this comes from animal sources.

The good news is that Active Iron is a vegetarian-friendly supplement. The unique whey protein formula is also free from artificial preservatives, sugar, wheat and gluten. Active Iron is the preferred choice for many vegetarians wanting to supplement their iron intake.

Pregnant Women

During pregnancy, the body needs more iron to transport oxygen around the body and to support your growing baby. The iron RDA for pregnant women increases from 18 mg to 27 mg. Many women find it a struggle to get all the iron they need during this time, and it can be very easy for pregnant women to develop inadequate iron levels. Once levels have become inadequate, it is nearly impossible to rebuild these levels through diet alone.

Active Iron is a great solution for pregnant women. Active Iron is safe for consumption prenatally, during pregnancy, and while breastfeeding. Its gentle formula is kind on your stomach, delivering much-needed iron in a non-constipating formula.

Heme Iron Supplements: Conclusion

Eating a healthy, balanced diet is the best way to ensure you get enough iron – both heme and non-heme. However, sometimes you might need some extra help. Athletes, vegetarians, and pregnant women all have an increased need for iron.

Selecting the right iron supplement is a big decision, as we must consider factors like lifestyle, side effects, and personal iron requirements.

Active Iron is recommended by healthcare professionals and loved by consumers. Its non-constipating formulation is clinically proven to provide 2X better absorption of iron,* and is 6X less likely*** to cause unwanted side effects. Active Iron is safe for pregnancy and is vegetarian-friendly, and can even be taken on an empty stomach.

If you want to increase your iron intake without unwanted side effects, try Active Iron today.


*Wang et al. 2017, Acta Haematological, 138: 223-232
** Garzon et al, Oman Med J. 2020 Sep; 35(5): e166
*** Ledwidge et al. Data on file.