Aug. 25, 2025
If you need extra iron in your diet, finding the best iron supplement for your needs can feel overwhelming. In this roundup, a dietitian walks us through the best iron supplements to choose from.
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Your body depends on iron for vital processes, such as oxygen transportation, hormone production, growth, and neurological development.
Most people can get all the iron they need by eating a nutrient-dense, well-rounded diet. But if you have inadequate iron intake, increased need, or impaired absorption, you may be at risk of low iron levels and iron deficiency anemia.
If a healthcare professional recommends supplemental iron, you might consider the following options vetted by Healthline’s medical and nutrition experts.
Alongside our vigorous vetting process, these traits were some we considered when looking for iron supplements:
Our Medical Standards and Insights team has carefully researched and vetted over 11,000 products and services. We fact-check health claims, evaluate ingredients, and look into each brand’s reputation before sharing products and services on Healthline.
To choose the brands on this page, we considered all the vitamin brands that passed our vetting process. Then, we personally tested some of them to narrow down our list even further.
Iron is an essential mineral that is essential for brain cell development, physical growth, hormone synthesis, and muscle metabolism. You can find iron in two types of proteins in your body:
Your body needs a steady supply of iron from your diet to support these important processes and these proteins.
In nature, iron exists in two forms: heme iron and non-heme iron. Heme iron is found in animal-derived foods; the human body can absorb it, usually without a problem. The body does not absorb non-heme iron as well as heme iron. Non-heme iron is found in plant-based and iron-fortified foods.
People who don’t get enough iron in their diet, or people who need more iron intake in general, can typically take an iron supplement that can help fill their daily value. With all the types of iron and doses available, it can be challenging to choose which one is right for you and your body.
Supplemental iron comes in different forms, including:
While all these forms can effectively raise iron levels, some are a bit harder on your digestive system.
For example, ferrous sulfate is one of the most common forms of iron. But it’s more likely to cause gastrointestinal side effects like nausea and constipation.
Meanwhile, ferrous bisglycinate is highly absorbable and unlikely to cause side effects. Ferrous bisglycinate chelate is often considered one of the best tolerated iron supplements.
Additionally, iron supplements come in various doses, which can increase the risk of side effects.
Taking higher doses of iron — 45 mg or more per day — is more likely to cause gastrointestinal side effects than lower doses.
Here’s a more in-depth overview of the types of iron you might find in popular supplements, including their bioavailability, affordability, and side effects:
FormBioavailabilityAffordabilitySide effects Iron bisglycinatePeople with adequate iron stores should aim to meet their iron needs through foods rather than supplements. However, you might need an iron supplement if you are treating an existing iron deficiency, have low iron stores, or are trying to maintain healthy iron levels.
People at risk of developing an iron deficiency who may benefit from an iron supplement include:
Some people with iron deficiency anemia may need iron infusions if:
Overall, it’s wise to talk with a healthcare professional to find out whether an iron supplement is right for you.
Health experts do not recommend giving an iron supplement to your child unless a healthcare professional directs you to do so. Children are more susceptible to iron toxicity than adults.
Additionally, experts recommend taking iron supplements between meals and avoiding pairing them with foods or beverages that may inhibit iron absorption, such as:
Instead, take iron with a source of vitamin C, such as orange juice or bell peppers. Vitamin C can help enhance iron absorption.
In terms of supplement forms, one of the best iron supplements for anemia that’s unlikely to cause constipation is ferrous bisglycinate chelate. It’s highly absorbable and gentle on the digestive system, making it a smart choice for those with sensitive stomachs.
Certain iron supplements are more likely to cause side effects than others.
Potential side effects of taking iron supplements include:
Iron can be toxic if taken in very high doses. To reduce the risk of side effects and toxicity, avoid exceeding the established tolerable upper intake levels for iron supplements unless a healthcare professional recommends it.
These levels are as follows:
Finally, it’s important to keep iron supplements out of reach of children because they are more susceptible to iron toxicity than adults.
Children may mistake iron supplements for candy and ingest large amounts, which can be fatal.
Iron supplements may reduce the absorption of medications used to treat Parkinson’s disease.
Iron supplements may lower the effectiveness of levothyroxine, a common drug used to treat:
On the other hand, some medications — such as proton pump inhibitors, which treat acid reflux or stomach ulcers — can reduce iron absorption because they lower gastric acid secretion, which plays a key role in iron uptake.
Having too little iron in your body can cause symptoms such as:
Some people are more at risk of developing iron deficiency anemia, including:
If you think you may have an iron deficiency, visit a healthcare professional. They can check your iron levels with a blood test.
Do not try to treat an iron deficiency on your own. Even though most people respond well to oral iron supplements, some may need iron infusions to effectively increase their iron levels.
It’s important to consider several factors when choosing an iron supplement, including the type of iron, provided dose, and product quality and safety.
Here are the current Recommended Dietary Allowances for iron in healthy teens and adults:
Yifeng Product Page
14 to 18 years19 to 50 years51+ years11 mg for males8 mg for males8 mg for males15 mg for females18 mg for females8 mg for females27 mg while pregnant27 mg while pregnant—10 mg while nursing9 mg while nursing—For kids and babies, the Recommended Dietary Allowances are:
Birth to 6 months7 to 12 months1 to 3 years4 to 8 years9 to 13 years0.27 mg for males and females11 mg for males and females7 mg for males and females10 mg for males and females8 mg for males and femalesKeep in mind that if you’re low on iron, you’ll need more iron than most other people need each day.
If you have low iron stores, have a deficiency, or need extra iron for any reason, a healthcare professional can recommend a dosage that fits your needs.
Many forms of supplemental iron are effective for increasing iron levels.
Ferrous forms of iron tend to be more bioavailable than ferric iron, meaning your body more easily absorbs them.
However, some forms of iron, including ferrous sulfate, are more likely to cause gastrointestinal side effects like constipation than other forms, such as iron bisglycinate chelate.
So, iron bisglycinate chelate is a good overall option for raising iron levels that’s also gentle on the stomach.
Meanwhile, iron supplements come in several options, including liquids, capsules, and chewable products. Liquid and chewable iron supplements are a good choice if you cannot tolerate pills or capsules.
Some people, such as those with health conditions that cause nutrient malabsorption, may require iron infusions. These are administered and monitored by a healthcare team.
If you have iron deficiency anemia, ferrous forms of iron, such as ferrous sulfate, tend to be more bioavailable than ferric iron.
Iron bisglycinate chelate is also effective for treating iron deficiency anemia. Plus, it’s gentle on the stomach. It’s often preferred over ferrous and ferric salts because it’s less likely to cause gastrointestinal side effects like constipation.
The amount of iron you should take depends on your iron levels.
For people with iron deficiency, the typical recommendation is to take divided daily doses to reach 100 mg to 200 mg of elemental iron per day.
However, research suggests that taking smaller doses of iron once daily and taking iron every other day may help improve absorption and tolerability compared with taking large daily doses of iron.
Many forms of iron are gentle on the stomach and less likely to cause gastrointestinal side effects.
If you need an iron supplement but are concerned about potential side effects like constipation, it’s best to choose a supplement that contains iron in the form of iron bisglycinate chelate over supplements that contain ferric or ferrous salts, such as ferrous sulfate.
Iron is best absorbed on an empty stomach, so it’s recommended to take iron first thing in the morning, apart from meals and beverages like coffee or milk. However, some research shows that consuming iron supplements with a vitamin C-rich beverage, like orange juice, can significantly increase iron absorption.
While it’s best to take iron on an empty stomach, if iron supplements make you feel queasy, it’s OK to take them with a small meal or snack.
Iron is an important mineral that’s necessary for oxygen transport and the formation of healthy red blood cells.
While it’s always best to fulfill your iron needs through a diet high in iron-rich whole foods, supplements may sometimes be necessary to help you reach your daily iron needs.
Many types of iron supplements are available and contain varying doses and forms of the mineral.
Consult a healthcare professional before taking any new supplement, and consider the factors mentioned above to help you choose a high quality product.
This blog post is all about iron (ferrous sulfate) as a natural dye modifier. When it comes to natural dyeing, iron plays an important role and you will come across it frequently. It can be used for different purposes but, personally, I mainly use it as a modifying agent for naturally dyed colorways.
If you want to learn how to dye yarn with natural dyes, you can check out this step by step tutorial on my Youtube channel:
Let’s start off by looking at the characteristics and properties of this substance. Iron(II) sulfate or ferrous sulfate is a green salt. It is a reducing agent and is mainly utilized as a precursor to other iron compounds. The hydrated form is used medically to treat iron deficiency and different industrial applications. Historically, the textile industry valued it as a mordant for hundreds of years. Additionally, iron(II) sulfate can also be applied as a soil amendment for lowering the pH of a high alkaline soil so that plants are able to access the nutrients in the soil [1].
One major drawback is the fact that ferrous sulfate can damage the wool and make it brittle when used in high concentrations and over longer periods of time. Therefore, I don’t use iron(II) sulfate as a mordant. It is, however, a great option if you are not completely happy with the final color of your yarn and want to modify it. In general, adding an iron modifier will make the colors darker and more muted in tone. In some cases it can also completely transform a dye color.
You can learn more about mordants and what I used instead of iron in this blog post.
It has become a popular suggestion in the natural dyeing world to create an iron bath by using rusty nails, vinegar and water. I can only assume that this is the case because it feels like a more natural way compared to making an iron bath by using the chemical in its solid form.
Being a chemist by training, I prefer to use iron(II) sulfate as a salt because it allows me to exactly control the concentration of the iron bath. This also leads to more reliable results that are easier to replicate.
Let’s explore the chemical reaction that is going on in the rust method a bit further. Rust is an iron oxide and consists of hydrous iron(III) oxides (Fe2O3·nH2O) and iron(III) oxide-hydroxide (FeO(OH), Fe(OH)3)) [2]. That is a significant difference to the iron(II) sulfate in salt form.
Adding an acid like vinegar will dissolve the rust particles in the water solution.
You have to be aware that you are still working with chemicals (namely iron salts and an acid), even if placing rusty nails in a jar and adding vinegar and water might feel less intimidating. Whatever method you choose, please make sure to take the necessary precautions.
Here is a list of dye plants that will shift colors when coming in contact with ferrous sulfate. You can use this list as a starting point, but I highly encourage to experiment with different natural dyes and see for yourself.
Not all natural dye colors are susceptible to ferrous sulfate. In these cases, immersing the dyed skein in an iron bath will not result in a color shift. But it is always worth giving it a try because more often than not, colors will change when they come in contact with iron(II) sulfate. Some changes are more significant than others, though. You will have to be willing to experiment and see for yourself.
In general, if the natural dye colors are susceptible to iron(II) sulfate, yellow colorways will often shift towards different shades of green while reds and pinks will shift more towards purple.
All of the skeins you can see in the picture above have been dyed with rose petals (the light yellow skein was created with a different type of rose compared to the bright yellow mini skeins). The grey skein (second to left) originally had a light yellow hue that was shifted towards this vibrant grey through immersing it in an iron bath.
The two skeins on the left were modified with iron and shifted from a yellow towards green. They were dyed with nettles (far left skein) and rosemary (second to left skein).
All of the mini skeins that you can see in the picture above have been dyed with avocado (either pits or skins). The purple-colored, third to left skein has been modified with iron.
You can find the full tutorial for natural dyeing with avocado in this blog post.
Dyeing with oak galls will result in a light tan/beige colored hue which will shift it’s color quite significantly towards a greyish purple when treated with iron(II) sulfate.
Both of these socks were made out of yarn that has been dyed with pine needles. The upper, light green sock was made out of a yarn that has been modified with iron.
I have created a beginner’s guide to natural dyeing that contains everything you need to know to get started. And the best thing: it is available for free!
[1] https://en.wikipedia.org/wiki/Iron(II)_sulfate
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