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Our dietitian narrowed down the best iron supplements on the market, evaluating ingredient quality, iron type, and price. Top picks include Thorne, Pure Encapsulations, and Klaire Labs.
Iron is a mineral necessary for many essential bodily processes.
Some people may have inadequate iron intake or impaired iron absorption. Plus, others have increased iron needs. As a result, they may be at risk for iron deficiency, which can lead to symptoms like fatigue, dizziness, and weakness.
Populations at risk for developing iron deficiency include:
infants and kids
athletes
people with heavy menstrual bleeding
pregnant people
anyone with gastrointestinal (GI) disorders or cancer
anyone who frequently donates blood
If you require supplemental iron, there are plenty of high quality iron products available that can help replenish your iron stores.
General price ranges with dollar signs ($–$$$) are indicated below. One dollar sign means the product is rather affordable, whereas three dollar signs indicate a higher price range.
Generally, prices range from $0.04 to $0.86 per serving or $10.35–42.99 per container, though this may vary depending on where you shop.
This article examines iron supplements based on the following criteria:
Quality: The iron supplements are tested for quality and purity, ideally by a third-party organization.
Iron type: The supplements contain easily absorbed forms of iron.
Other nutrients: The supplements are free of nutrients that impair iron absorption and may contain nutrients that enhance absorption.
Dose: The supplements contain an effective dose of iron.
Price: We included products to suit a variety of budgets.
Why you can trust us
Every brand and product on our list has been vetted to ensure that it aligns with Healthline’s brand integrity standards and approach to well-being. Each product in this article:
adheres to allowable health claims and labeling requirements per Food and Drug Administration (FDA) regulations
is manufactured in facilities that adhere to the current good manufacturing practices (CGMPs) established by the FDA
is produced by a medically credible company that follows ethical, legal, and industry best standards
is made by a company that provides objective measures of trust, such as having its supplements validated by third-party labs
Heme iron: a form of iron that is found in animal-derived foods and is more readily absorbed by the human body
Non-heme iron: a form of iron that is found in plant-based and iron-fortified foods and is not as well absorbed as heme iron
You can also take iron in supplement form. Iron supplements may be necessary for those who don’t get enough iron in their diet and those who have increased iron needs.
For those who need an iron supplement, choosing the right product can seem overwhelming because so many different types of iron supplements are available.
The most popular types are ferrous and ferric iron salts, which include:
ferric sulfate
ferrous gluconate
ferrous sulfate
ferric citrate
Because of its higher solubility, ferrous iron tends to be more bioavailable than ferric iron, which means it’s easier for your body to absorb.
You may also find other forms of iron, such as:
heme iron polypeptides
carbonyl iron
iron amino acid chelates
polysaccharide-iron complexes
Some forms of iron, such as ferrous sulfate, are more likely to cause GI disturbances, including constipation, than other forms, such as iron bisglycinate chelate.
Form
Bioavailability
Affordability
Side effects
Iron bisglycinate chelate
Highly absorbable
A bit more expensive compared to other forms of iron
Minimal gastrointestinal side effects compared to ferrous sulfate
Ferrous sulfate
Well-absorbed
Inexpensive
May cause gastrointestinal side effects like constipation in high doses
Ferric sulfate
Less bioavailable than iron bisglycinate chelate and ferrous sulfate
Inexpensive
May cause gastrointestinal side effects like constipation in high doses
Ferrous fumarate
Well-absorbed
Inexpensive
May cause gastrointestinal side effects like constipation in high doses
people with certain forms of cancer, such as colon cancer
people with GI disorders such as celiac disease and Crohn’s disease
people with heart failure
people who frequently donate blood
athletes
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.
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Some people with iron deficiency anemia may need iron infusions if:
they do not respond to oral iron
their bodies can’t properly absorb iron
their iron losses are too great to be treated with oral supplements
Overall, it’s wise to talk with a healthcare professional to find out whether an iron supplement is right for you.
It’s important to consider several factors when choosing an iron supplement, including the type of iron, provided dose, and product quality and safety.
Dosing
Talk with a healthcare professional about proper dosing.
Keep 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.
Product quality and safety
When shopping for an iron supplement, look for high quality products that have undergone third-party testing for quality and purity by credible organizations such as USP and NSF International.
It’s also important to choose products that are manufactured in facilities that adhere to the CGMPs established by the FDA.
Iron deficiency anemia is typically treated with daily oral iron supplements for at least 3 months to replenish iron stores. For some people, healthcare professionals may recommend continuing to take iron supplements even after hemoglobin levels return to normal.
For those with iron deficiency, taking an iron-only supplement is a good idea because other nutrients commonly found in multivitamins, such as calcium, may inhibit iron absorption.
Additionally, it’s recommended to take iron supplements between meals and avoid pairing them with foods or beverages that may inhibit iron absorption, such as:
tea
coffee
milk
Instead, it can be a good idea to take iron with a source of vitamin C, such as orange juice or bell peppers, because it can help enhance iron absorption.
Certain iron supplements are more likely to cause side effects than others. Also, iron can be toxic if taken in very high doses.
This is why it’s important to discuss proper dosing with a healthcare professional before starting to take iron supplements.
Potential side effects of taking iron supplements include:
constipation
diarrhea
nausea
abdominal pain
To reduce the risk of side effects and toxicity, it’s best to avoid exceeding the established Tolerable Upper Intake Levels for iron supplements unless a healthcare professional recommends it. These levels are as follows:
40 mg per day for babies and kids
45 mg per day for teens and adults
Finally, it’s important to keep iron supplements out of reach of children because children are more susceptible to iron toxicity than adults. Children may mistake iron supplements for candy and ingest large amounts, which can be fatal.
Drug interactions
Iron supplements may also interact with certain medications.
For example, iron supplements may reduce the absorption of medications used to treat Parkinson’s disease and may lower the effectiveness of levothyroxine, a common drug used to treat:
hypothyroidism
goiter
thyroid cancer
On the other hand, some medications — such as proton pump inhibitors, which are used to treat acid reflux or stomach ulcers — can reduce iron absorption because they lower the secretion of gastric acid, which plays a key role in iron uptake.
Having too little iron in your body can cause symptoms such as:
fatigue
weakness
difficulty concentrating
shortness of breath
Some people are more at risk for developing iron deficiency anemia, including:
people with heavy periods
pregnant people
people with medical conditions that cause malabsorption of nutrients
If you think you may have an iron deficiency, it’s important to visit a healthcare professional to get appropriate testing.
Do not try to treat an iron deficiency on your own. Even though most people respond well to oral iron supplements, some people may need iron infusions to effectively increase their iron levels.
Yes, for most people. Oral iron supplements are usually the first choice for treating iron deficiency anemia.
However, some people with iron deficiency anemia may need iron infusions if:
they don’t respond to oral iron
they can’t properly absorb iron
their iron losses are too large to be treated with oral iron supplements
What is the best form of iron supplement to take?
This depends on your specific health needs.
There are many forms of bioavailable iron on the market. The most popular ones are ferrous and ferric iron salts, which include:
ferric sulfate
ferrous gluconate
ferrous sulfate
ferric citrate
Certain types of iron, such as ferrous bisglycinate chelate, are less likely to cause GI symptoms such as constipation than other forms, like ferrous sulfate.
How can I boost my iron levels quickly?
It takes time to increase your iron levels, especially if your blood levels are low. If you have low iron, a healthcare professional can recommend a personalized treatment plan.
Generally, iron deficiency anemia is treated with daily oral iron supplements for at least 3 months in order to replenish tissue iron stores.
How much iron should I take in supplement form?
The amount of iron you may take will depend on your iron levels.
For people with iron deficiency, the typical recommendation is to take iron in divided daily doses to reach 100–200 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.
Ask a healthcare professional for specific dosing instructions.
Never take high dose iron pills unless recommended and monitored by a healthcare professional.
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Is it OK to take iron supplements every day?
Yes, it can be OK for those who need it.
But most people do not need to take iron daily, and taking too much can lead to iron toxicity.
However, people who have chronically low iron stores or inadequate dietary iron intake may need to take a daily iron supplement to maintain optimal iron levels.
If you have questions about iron supplement dosing and how often you should be taking your iron supplement, reach out to a doctor for advice.
What can I take with iron supplements to avoid constipation?
There are a few ways you can avoid or ease constipation when taking iron supplements. You can try spreading the recommended dose into a few smaller doses throughout the day and staying hydrated.
It’s also a good idea to start by taking half the recommended dose and slowly increasing the amount over the course of a few days until you reach the recommended dose.
Additionally, consider the type of iron before purchasing a supplement. For example, ferrous sulfate is more likely to cause constipation than other forms, such as iron bisglycinate chelate.
If you’re still experiencing constipation, a stool softener may be helpful. Just be sure to talk with a healthcare professional before trying this.
Useful supplement shopping guides
Check out these two articles to help make supplement shopping a breeze:
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.
Remember to consult a healthcare professional before taking any new supplement and consider the factors mentioned above to help you choose a high quality product.
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Makinen KK. (2016). Gastrointestinal disturbances associated with the consumption of sugar alcohols with special consideration of xylitol: Scientific review and instructions for dentists and other health-care professionals. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5093271/