Although most people can meet their iron needs through diet alone, being pregnant, being an endurance athlete, having heavy menstrual bleeding, or having gastrointestinal conditions that decrease iron absorption can increase the risk of iron deficiency. Iron deficiency is the cause of 50% of all anemias, a condition where the body doesn’t have enough healthy hemoglobin to carry oxygen through the blood to your cells, leading to fatigue, dizziness, shortness of breath, and cold hands and feet. ( 1 , 2 )
No two iron supplements or multivitamins are alike, as they can contain various types of iron with vastly different absorbability, doses, forms, costs, and additional ingredients to support absorption and health. Our team of experts assessed these factors in addition to third-party testing and additional features to find the best iron supplements on the market for your unique needs.
Best iron supplement overall
New Chapter Fermented Iron Complex is our top choice for an iron supplement. It’s designed to support blood health and iron absorption with a highly absorbable form of iron and additional nutrients, including vitamin C, zinc, vitamin B12, and vitamin E. The addition of whole food complexes, including ginger, peppermint, cardamom, and coriander, may support digestion and help soothe potential symptoms of supplemental iron.
Medical disclaimer: This article is intended for educational and informational purposes only. It is not intended as a substitute for medical advice. For health advice, contact a licensed healthcare provider.
Our picks for the best iron supplements
- Best overall: New Chapter Fermented Iron Complex
- Best for pregnancy: Ritual Essential for Women Prenatal Multivitamin
- Best for women: Nutricost Iron for Women
- Best vegan: Future Kind Vegan Iron and Vitamin C
- Best for sensitive stomachs: Performance Lab Iron Complex
- Best for anemia: Nature Made Iron Tablets
- Best liquid: Floradix Iron and Herbs
Compare iron supplements
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| New Chapter Fermented Iron Complex | Ritual Essential for Women Prenatal Multivitamin | Nutricost Iron for Women | Future Kind Vegan Iron Supplement with Natural Vitamin C | Performance Lab Iron Complex | Nature Made Iron | Floradix Iron and Herbs | |
| Rating | |||||||
| Price | $27.00 | $39.00 | $22.95 | $19.99 | $29.00 | $10.59 | $22.99 |
| Dose | 9 mg | 18 mg | 65 mg | 18 mg | 14 mg | 65 mg | 10 mg |
| Other ingredients | Vitamin C, vitamin E, zinc, folate, B12, turmeric, ginger, aloe, peppermint, coriander, cardamom, artichoke, schizandra berry, maca, chamomile, ferment media, lactobacillus acidophillus | Vitamin D3, vitamin E, folate, vitamin B12, biotin, choline, iodine, magnesium, boron, omega-3 fatty acid, vitamin K2 | Vitamin C, folate, vitamin B12 | Vitamin C | Vitamin C | None | Thiamin, riboflavin, vitamin B6, vitamin B12, extract featuring carrot root, stinging nettle, spinach leaves, fennel seed, couch grass root, kelp, hibiscus, yeast, rose hip, wheat germ, pear, blackberry, cherry, orange, red beet, and white grape |
Best iron supplement overall: New Chapter Fermented Iron Complex
Key product features
What you should know
New Chapter Fermented Iron Complex contains 9 milligrams (mg) of iron and other nutrients like vitamin C, to help increase absorption, and folate, B12, and zinc to help support healthy blood levels of hemoglobin and myoglobin. Fermented media increases the availability of iron in the supplement, and various herbs and plant compounds help minimize symptoms of digestive upset.
- Adding lactic acid bacteria and fermented media increases the bioavailability of iron, helping you get the most of the 9 mg of ferrous fumarate included in the supplement.
- At $0.45 per serving, this iron supplement is an excellent value compared to other options on our list, especially since it includes multiple blood-boosting nutrients.
- This formula is best for menstruating people and those with celiac disease or other digestive disorders that increase the risk of iron deficiency who want to naturally support energy and overall health with an absorbable, whole-food formula.
- While this supplement is not third-party tested for purity and potency, it is NSF-certified gluten-free, making it an ideal choice for anyone with celiac disease.
Why we like New Chapter Fermented Iron Complex as best overall
Supplemental iron is notoriously hard to absorb and utilize, but not everyone can get what they need from food sources alone. New Chapter Fermented Iron Complex combines ferrous fumarate, an iron salt that contains 33% elemental iron (more than other common forms of iron salts used in supplements), the blood-building nutrients folate and vitamin B12, and whole food complexes to support digestion and absorption. ( 3 )
To enhance iron absorption, this complex is delivered in a fermented media, which increases its bioavailability, or how well it can be absorbed and used by your body. In addition, vitamin C is also included to aid absorption. (4 ) Taking it on an empty stomach or with juice alone will also help with absorption. ( 5 )
Research has found that lactic acid fermentation of vegetables and wheat can significantly increase the amount of iron absorbed by the body. ( 6 , 7 ) New Chapter uses lactic acid bacteria, including Lactobacillus acidophilus, Bifidobacterium bifidum, and Lactobacillus rhamnosus , to ferment a media of soy flour, orange peel powder, alfalfa powder, and Saccharomyces cerevisiae (brewer’s yeast).
While iron deficiency is the most common cause of anemia, it’s not the only one. This complex also includes 30 micrograms (mcg) of vitamin B12 and 333% of the daily value of folate, two essential nutrients for building healthy levels of red blood cells in the body. ( 8 , 9 )
But with only 9 milligrams (mg) of iron, this supplement may not provide enough iron to correct a deficiency, as most people with iron deficiency anemia need between 150-200 mg of elemental iron per day. ( 10 ) It’s best reserved for those looking to support healthy blood levels, not correct them.
As common side effects of iron supplements often include constipation and an upset stomach, you’ll also find various plant compounds to help ease your stomach, including ginger, peppermint, and coriander. ( 3 )
While New Chapter is a well-known and reputable company, it does not utilize third-party purity and potency testing. This supplement is, however, NSF-certified gluten-free, making it an excellent choice for anyone with celiac disease, an autoimmune disorder that creates a reaction to gluten, damaging the small intestine. ( 11 )
What customers are saying
Most of the 1,887 Amazon reviews for this supplement are positive, with 81% of Amazon customers giving it a 5-star rating. Many proclaim that this supplement raised iron levels quickly and with minimal side effects.
“Tiny little pill keeps my iron levels up and doesn’t mess with digestion at all! Perfect blend,”
Renne W., Amazon
However, not everyone is happy with the side effects, and many people state that taking them on an empty stomach does lead to nausea. “Easy to swallow, but still constipate me even though it’s fermented,” verified user Pat commented.
Specs
| Form | Tablet |
| Iron type | Ferrous fumarate |
| Dose | 9 milligrams |
| Cost per serving | $0.45 |
| Third-party tested | No |
| Additional features | NSF-certified gluten-free |
Best iron supplement for pregnancy: Ritual Essential for Women Prenatal Multivitamin
Key product features
What you should know
Ritual Essential for Women Prenatal Multivitamin is made from ingredients you can trace and includes 12 key nutrients needed for healthy conception and pregnancy, including 18 mg of ferrous bisglycinate, a form of iron that’s gentle on the stomach. ( 12 )
- Our product testers found this multivitamin to have fewer digestive side effects than other multivitamins they have tried. The slight mint or citrus flavor is subtle, making taking the vitamins a little more pleasant.
- This prenatal includes iron, B12, and folate to support pregnancy’s blood-building requirements and other nutrients essential for healthy fetal development, such as omega-3 fatty acids, magnesium, and choline.
- A monthly subscription is required to purchase, and the cost per serving is $1.30, making it a more expensive iron supplement than other options.
- This supplement is best for pregnant women or those trying to become pregnant, as it has nutrients specific to supporting pregnancy.
Why we like Ritual Essential for Women Prenatal Multivitamin as best for pregnancy
Ritual Essential for Women Prenatal Multivitamin stands out as the best iron supplement for pregnant women because it features 12 nutrients essential for a healthy pregnancy, offers convenient subscription options, and is third-party tested.
Each serving of Ritual Essential for Women Prenatal Multivitamin provides 18 mg of iron in the form of ferrous bisglycinate. This highly bioavailable chelated iron salt is known for causing fewer gastrointestinal side effects compared to other iron types. A 2023 meta-analysis and review found that supplementing with ferrous bisglycinate for 4–20 weeks significantly increased serum hemoglobin levels and resulted in fewer stomach-related issues. ( 12 ) Reduced instances of nausea and upset stomach are particularly beneficial for many women, especially during early pregnancy when nausea is already a common challenge.
Our team of product testers found this supplement easy to swallow two at a time (for one serving). While one experienced no negative side effects, another reported fewer digestive upsets than with other multivitamins.
Even though the cessation of menses occurs during pregnancy, iron requirements are higher and continue to increase as fetal development continues. As requirements increase from 0.8 mg per day in the first trimester to 7.5 mg per day in the second trimester, Ritual’s prenatal provides support with 18 milligrams. ( 12 )
In addition to iron, this supplement also provides other red blood cell-building nutrients like vitamin B12 and folate, along with nutrients essential to healthy fetal brain and neural tube development, like choline and omega-3 fatty acids. Nutrients like magnesium , choline, boron, and vitamin K3 support bone development when paired with a calcium-rich diet. ( 13 , 14 )
While it’s always important to make sure you can trust that a supplement has the ingredients it says it does (and nothing else), this is especially important during pregnancy. Ritual uses traceable ingredients, so you know the origin and final manufacturing place of all ingredients, and requires all suppliers to provide certificates of analysis for all ingredients.
While some Ritual products are USP-verified for purity and potency or Informed-Sport Certified, this particular vitamin has not received any third-party testing verifications, although all Ritual products are third-party tested for heavy metals and contaminants.
Specs
| Form | Capsules |
| Iron type | Ferrous bisglycinate |
| Dose | 18 milligrams |
| Cost per serving | $1.30 |
| Third-party tested | Yes |
| Additional features | Non-GMO project certified, vegan, gluten-free |
Best iron supplement for women: Nutricost Iron for Women
Key product features
What you should know
Nutricost Iron for Women is a budget-friendly option that includes 65 mg of iron, B12, folate, and vitamin C to help support healthy blood levels in women during menstruation, pregnancy, and childbirth.
- Nutricost Iron for Women contains 65 mg of iron from a combination of ferrous fumarate and ferrous bisglycinate, two iron salts that are more bioavailable than some other forms.
- With 180 servings in each bottle, the price is incredibly cost-effective at just $0.13 per serving, and costs even less with a subscription.
- This supplement is best for women who are at a higher risk of anemia or low iron levels related to heavy periods, pregnancy, or childbirth.
- The high amount of iron and the type of iron used (ferrous fumarate) may cause digestive upset or constipation in some people. ( 3 )
Why we like Nutricost Iron for Women as best for women
Menstruation, pregnancy, and childbirth all put women specifically at a higher risk for low iron levels and iron deficiency anemia. Worldwide, 20% of women of childbearing age have iron deficiency anemia, making a budget-friendly and potent iron supplement like Nutricost Iron for Women particularly valuable. ( 15 )
The 65 mg of iron comes from a combination of ferrous bisglycinate, a highly absorbable chelated iron salt, and ferrous fumarate, an iron salt containing around 33% elemental iron. While ferrous bisglycinate is generally more gentle on the stomach, some people may experience nausea or constipation related to ferrous fumarate. ( 3 )
In addition to iron, you’ll also find 50% of the daily value for folate and 20,830% for vitamin B12—two B vitamins essential for healthy red blood cell production. ( 16 ) Deficiency in either of these nutrients can lead to a condition known as megaloblastic anemia, where your stem cells make abnormally large red blood cells that reduce the number of healthy red blood cells in the body, leading to anemia. ( 16 )
Each serving also includes 50% of the daily value of vitamin C to aid in iron absorption. While older studies demonstrated that vitamin C decreases the absorption of vitamin B12, additional human studies have not found proof that this is what happens in the body. ( 17 )
Because of blood loss during menstruation and childbirth and the increased need for healthy red blood cells in pregnancy, Nutricost Iron for Women helps support multiple aspects of healthy blood development throughout a woman’s childbearing years.
Every bottle has 180 servings, which brings the cost per serving down to just $0.13 per pill, and even less with a subscription, making this supplement incredibly affordable.
This supplement is non-GMO and appropriate for people on a vegetarian and/or gluten-free diet. While the bottle states that it is third-party tested, testing results or lab information is not readily available on the website for verification.
What customers are saying
Most Amazon customers find this supplement easy to take and effective, but customers cite a wide range and scope of negative side effects.
Some customers found this supplement to be more effective than other iron supplements they’ve tried in the past.
“Since starting this, my iron levels have been much higher. I think it is a good product that is absorbed into my body better than other iron supplements I’ve used,”
Drew P., Amazon
For some, the form of iron and the amount of iron may be too much. “The pill size isn’t uncomfortable or hard to swallow,” says verified Amazon reviewer Amber. However, taking this iron supplement resulted in significant digestive issues. “For me, the heartburn, indigestion, bloat and other assorted intestinal (ew) issues really slowed me down,” she added.
Specs
| Form | Capsule |
| Iron type | Ferrous fumarate, ferrous bisglycinate |
| Dose | 65 milligrams |
| Cost per serving | $0.13 |
| Third-party tested | Yes |
| Additional features | Gluten-free, non-GMO, vegetarian |
Best vegan iron supplement: Future Kind Vegan Iron and Vitamin C
Key product features
What you should know
Future Kind Vegan Iron and Vitamin C is a third-party-tested, vegan iron supplement with chelated iron and vitamin C. It’s free from gluten, wheat, soy, nuts, yeast, sugar, artificial colors, flavors, and preservatives, for a practical and minimalist approach to supplementing iron.
- This is a vegan iron supplement with minimal ingredients, offering a highly absorbable type of iron and 100% of the daily value.
- The cost per serving is $0.67, which is higher than that of many other supplements containing only iron and vitamin C.
- Future Kind Vegan Iron and Vitamin C is an excellent match for anyone who values a certified vegan supplement with minimal allergens and ingredients.
- This uses the chelated iron salt ferrous bisglycinate, which may be better absorbed and tolerated than other supplemental iron forms.
Why we like Future Kind Vegan Iron and Vitamin C as best vegan
Future Kind Iron with Vitamin C is a vegan formula with 18 mg, or 100% of the daily value, of iron from ferrous bisglycinate, a highly absorbable chelated iron salt that’s easy on the digestive system, making it ideal for vegans. ( 10 )
Some of the most absorbable and highly bioavailable food sources of iron come from meat, which can be a problem for vegans, who avoid animal products. Non-heme iron, found in plant foods like beans, nuts, spinach, and fortified grains, is about half as bioavailable as the heme iron found in meat, poultry, and seafood. ( 16 )
The iron is combined with 56% of the daily value of vitamin C from acerola cherry to support bioavailability, and is free from gluten, soy, wheat, nuts, yeast, artificial colors, preservatives, and flavors.
Future Kind’s iron supplement is third-party tested, and you can view the certificate of analysis on the website for transparency regarding the findings of the heavy metals and bacteria from previous testing.
It’s also free from artificial colors, preservatives, or flavors, and includes only rice flour in the vegan capsule, reducing the need for additional fillers. While the capsules are vegan, they’re also free from gluten and major allergens, including soy, wheat, nuts, sugar, and yeast.
The cost per serving is $0.67, which is higher than that of many other supplements containing only iron and vitamin C.
What customers are saying
Most Amazon reviewers praise the ingredients used in Future Kind Iron with Vitamin C, as they’re free from fillers, vegan, and seem to really work. One verified purchaser known as KHM2447 stated,” One pill that doesn’t really have any additives and helps boost my iron intake.”
Several users agree that the pills are small, easy to swallow, and easy to tolerate as well.
“These are perfectly small and easy to swallow, due to the coating it goes down smooth. This has helped my ferritin and iron levels improve 2 months in, already back to normal.”
Jazz G., Amazon
Unfortunately, not everyone has been able to tolerate these iron supplements, which is a fair warning to anyone who has an especially sensitive stomach. “These hit me with a nausea worse than ever before,” Lindsey K. reports. So while most customers found them to be more gentle on the stomach, nausea, and gastrointestinal upset is still a possibility.
Specs
| Form | Capsule |
| Iron type | Ferrous bisglycinate |
| Dose | 18 milligrams |
| Cost per serving | $0.67 |
| Third-party tested | Yes |
| Additional features | Free from gluten, wheat, soy, yeast, nuts, and sugar |
Best iron supplement for sensitive stomachs: Performance Lab Iron Complex
Key product features
What you should know
Performance Lab Iron Complex features 14 mg of chelated iron and vitamin C to increase absorption with fewer digestive side effects.
- Performance Lab Iron Complex may work best for those with sensitive stomachs, since chelated iron is better tolerated by many people who may otherwise have digestive upset from iron supplements.
- Subscribing to a four-month supply can save you 32%, bringing the cost per serving down from $0.97 to just $0.66.
- This supplement is safe for most food allergies as it’s free from gluten and major allergens.
Why we like Performance Lab Iron Complex as best for sensitive stomachs
Performance Lab Iron Complex is our pick for the best iron supplement for sensitive stomachs because of its patented form of iron, designed to improve absorption, and its mid-range dose.
Performance Lab Iron Complex provides 14 mg of iron along with 67% of the daily value for vitamin C to enhance digestibility. While Performance Lab does not specify which form of iron it contains, it does describe the patented NutriGenesis® process as one that features chelated minerals, a process of binding the mineral to an amino acid, helping the iron be more bioavailable and absorbable.
While gastrointestinal side effects like constipation, diarrhea, nausea, vomiting, gas, and stomach pains occur in 70% of people who take iron supplements, chelated iron often minimizes those effects. ( 3 ) Taking iron daily, especially on an empty stomach, increases the amount of iron you can absorb, but can also increase unwanted digestive side effects. While chelated iron may help minimize the side effects, lower doses or altered regimens, as recommended by your doctor, may also help. ( 3 )
This iron supplement is available only through Performance Lab’s website. Performance Lab utilizes third-party testing to verify the purity and potency of its products, so you can be sure you’re getting what they claim.
While the cost per serving is $0.97, higher than many other supplements featuring just iron and vitamin C, you can save 10% with a one-month subscription and up to 32% by subscribing to a four-month supply.
Specs
| Form | Capsule |
| Iron type | Chelated |
| Dose | 14 milligrams |
| Cost per serving | $0.97 |
| Third-party tested | Yes |
| Additional features | Vegan, non-GMO, soy-free, gluten-free, allergen-friendly |
Best iron supplement for anemia: Nature Made Iron Tablets
Key product features
What you should know
These small but mighty iron tablets contain 65 mg of iron in each serving, quickly replenishing iron levels at a fraction of the cost of other supplements.
- Our testers found quick relief from anemia symptoms of fatigue and cold hands with this supplement, and experienced minimal side effects.
- At $0.06 per serving, these iron tablets are a great value, especially as they’re USP-verified, ensuring a safe and pure product.
- The 65 mg dose of iron may be too high for some people to take daily, but it’s appropriate for anyone with anemia who needs a higher amount to restore or maintain adequate iron levels.
- The tablets are small (about the size of a pencil eraser) and easy to swallow.
Why we like Nature Made Iron Tablets as best for anemia
Nature Made Iron tablets have a substantial 65 mg of iron from ferrous sulfate, or 361% of the daily value for iron. Since your body cannot absorb all of that iron, and certain causes of anemia may lead you to absorb even less, this higher amount is helpful for people with anemia.
To correct iron levels low enough to qualify as having iron deficiency anemia—iron levels of less than 10 millimoles per liter or ferritin levels of less than milligrams per liter—you may need more iron to help your body quickly absorb and increase levels. ( 2 )
The most common side effects of taking more than 45 mg of iron at a time are nausea, upset stomach, and constipation, but taking these tablets with food may help reduce those symptoms. ( 19 ) And as the symptoms of anemia can include fatigue, headaches, dizziness, restless leg syndrome, and even heart or pregnancy complications, supplementing with a higher dose until levels are within a normal range may be advised—but always check with a healthcare provider before taking supplement doses higher than the recommended dietary allowance (RDA).
One team product tester is a long-time user of this iron supplement and found quick relief from fatigue and cold hands related to iron deficiency, without experiencing any adverse side effects.
Not only are these iron supplements third-party tested, but they’re also USP-verified for purity and potency—one of the highest standards for supplements on the market—so you can be sure you’re getting exactly what the bottle says.
Our team found this pill to be about the size of a pencil eraser, easy to swallow, and with little aftertaste. As a highly reputable supplement free from gluten, animal products, and artificial flavors and colors, it only costs $0.06 per serving, making it a cost-effective, high-value iron supplement.
What customers are saying
Nature Made Iron Tablets are a popular and well-liked option, with 44,754 total Amazon ratings for an average or 4.7 out of 5 stars, and 2,104 Amazon reviews. Many users who struggle with anemia have found quick relief with this supplement.
“I take this supplement daily. It has helped my anemia greatly!”
Lisa C, Amazon
While the high dose of iron in these supplements may cause constipation and nausea, which are some of the most commonly noted side effects, others have found it to be better than some alternatives.
“They do constipate you. Even with food I get nausea,” reports reviewer Jason H. However, Amazon reviewer Nicole had a different experience. “Some iron pills make my stomach hurt but this one doesn’t, I have anemia and decided to purchase this one. I’m starting to feel better after 2 weeks taking it,” she says.
Specs
| Form | Tablet |
| Iron type | Ferrous sulfate |
| Dose | 65 milligrams |
| Cost per serving | $0.06 |
| Third-party tested | Yes |
| Additional features | USP-verified, gluten-free |
Best liquid iron supplement: Floradix Iron and Herbs
Key product features
What you should know
Floradix Iron and Herbs provides 10 mg of iron in liquid form with ferrous gluconate, plus four B vitamins to support energy levels and a blend of 10 different herbs and extracts to support digestion and absorption.
- The cost of $1.16 per serving is higher than many other iron supplements and, as a liquid with no added preservatives, it needs to be stored in the refrigerator.
- Floradix Iron and Herbs includes a proprietary blend of 10 different herbs and extracts with unknown amounts, so be sure to check for any drug interactions or allergies.
- As a liquid iron supplement, Floradix Iron and Herbs may be easier for children and anyone who has difficulty swallowing pills. The 10 mg dose of iron meets the RDA for children, males, and older adult females.
Why we like Floradix Iron and Herbs as best liquid
Liquid supplements tend to be easier for some to swallow, especially children and older adults who may have difficulty with large pills. Floradix Iron and Herbs include 10 mg of iron from ferrous gluconate, an iron salt effective at increasing iron levels and keeping them stable. ( 20 ) Besides ferrous gluconate, this formulation also includes over 100% of the daily value for B vitamins thiamin, riboflavin, B6, and B12. If you have inadequate levels of B vitamins, replenishing them with iron can help improve energy levels. ( 21 )
With the lower dose of 10 mg of iron, some people may find that they’re better able to tolerate or have less severe nausea or constipation than they would with higher doses. Still, it may not be enough to correct an iron deficiency.
In Floradix Iron and Herbs, you’ll also find a proprietary blend of 10 different herbs and extracts, including stinging nettle, fennel, rose hips, and hibiscus, that claim to support digestion and absorption. While the formula includes 6 grams (g) of the proprietary blend, it’s unclear how much of each herb and extract is included.
As it’s free from preservatives, once opened, this supplement should be stored in the refrigerator to keep it fresh and prevent spoiling. The liquid is sweet in flavor and includes a variety of fruit juices and honey for 2 g of added sugars and 10 calories in each serving.
While the website claims this product is purity tested, the results are not shared, and it does not state that the testing is done by a third party. This is a voluntary standard that provides assurance of non-biased testing and reporting among supplements, so this lowered this supplement’s rankings a bit.
What customers are saying
With 1,711 five-star reviews on Amazon, the Floradix Iron and Herbs liquid supplement is a popular and well-liked choice. “This is the only and I mean ONLY iron supplement that doesn’t give you a stomach ache or constipation,” says Amazon reviewer Sadie S. “The taste is nasty but I add it to a little bit of apple juice and that helps tremendously,” she adds.
The poor taste is by far the most common complaint, but most reviewers who are not fans of the taste on its own find it just fine when mixed with another liquid (cream soda, orange juice, and smoothies are popular options).
Specs
| Form | Liquid |
| Iron type | Ferrous gluconate |
| Dose | 10 milligrams |
| Cost per serving | $1.16 |
| Third-party tested | No |
| Additional features | Non-GMO, vegetarian, lactose-free, alcohol-free |
How we test iron supplements
Supplements are key for filling nutritional gaps and enhancing our health. The right supplement can help correct a deficiency, improve mental clarity, enhance performance or recovery, or relieve specific physical symptoms. Here’s how we rate the iron supplements we test. You can read our full supplement testing methodology here .
Testing criteria
Efficacy—30%
Consumers turn to dietary supplements to achieve specific health benefits, so we examine whether a supplement delivers its promised benefits. Here’s what we look for:
- Clinical evidence
- Calories per serving
- Dose efficacy
- Synergistic effects
- Proprietary blends
Efficacy—40%
The number one goal when taking an iron supplement is to have that supplement actually restore or retain your iron levels. We give the most weight to this category because we want the supplement to actually work as it’s intended. We examined whether the iron supplement contains ingredients that scientific evidence supports as being effective in the appropriate doses and whether it includes ingredients that will help or harm this efficacy.
Here’s what we look for in our scoring of efficacy:
- Clinical evidence
- Calories per serving
- Dose efficacy
- Synergistic effects
- Proprietary blends
Safety and side effects—35%
We examined the potential health risks, adverse side effects, and safety profiles of the ingredients and formulations of these iron supplements. Supplements are not regulated or tested in the same manner as medications, so participating in quality control by using GMP-certified manufacturing processes and utilizing third-party certifications and seals of verifications offers the most assurance of product safety. As a consumer, you should be well aware of any potential risks or side effects that may result as you use various supplements. We evaluate:
- Reported side effects
- Third-party testing
- Manufacturer accreditation
Value—20%
The cheapest option is not always the best choice—just because a product is expensive does not mean it’s valuable. We compared ingredients, quality, and effectiveness against the cost to determine which supplements offer the most value and return on investment. We looked closely at the following:
- Price per serving
- Subscription discounts
Customer experience—5%
We can research ingredients and processes as thoroughly as possible, but actual user experience offers invaluable insight into how getting and using the product actually works. We reviewed customer ratings and reviews on third-party sites, like Amazon, to get a clear picture of the themes customers are experiencing with each product.
- Ease of purchase
- Shipping and returns
- Customer support
How to choose an iron supplement
To choose the best iron supplement for your needs, you may want to consider the following and consult your doctor to find the best option for your needs:
Type of iron
Iron salts are more easily absorbed than other types of iron, which is why many iron supplements are made of ferrous gluconate, sulfate, or fumarate. Another way to increase the absorption and decrease the digestive symptoms of iron supplements is to chelate them or bind the iron to an amino acid. This protects the iron from inhibitors for better absorption and easier digestion. A common iron chelate is ferrous bisglycinate.
Dose
Preventing low iron levels may require a smaller dose than if you have been diagnosed with anemia or inadequate iron and need to quickly increase your iron levels. While some iron supplements have more than 300% of the daily value, your body won’t be absorbing the entire amount. Higher doses of iron are also more likely to result in digestive symptoms like constipation, nausea, and upset stomach. Symptoms may dissipate if a lower dose is tried.
Additives
Some iron supplements include animal products, gluten, or other allergens that may not be appropriate for everyone. Look at the label to ensure it’s free from any allergens or ingredients you want to avoid.
Other nutrients
Many iron supplements include more than just iron. From other blood builders like vitamin B12 and folate to vitamin C to help aid absorption, or herbs to support digestion, you will want to review the ingredient list and nutrient fact label to ensure you want or need any featured extras.
Testing
Supplements are not regulated by the Food and Drug Administration (FDA) like medications. Buying supplements from a reputable brand that does in-house and third-party testing is ideal, so you can be assured that the product has exactly what it says and is free from potentially harmful ingredients like heavy metals or other ingredients you may have negative interactions with.
Benefits of iron supplements
If you struggle with low iron levels, adding an iron supplement to your routine can have several health benefits, ranging from improved mood and energy to healthier hair. Here are a few potential health benefits from taking a multivitamin that includes iron or an iron-specific supplement.
Improved energy levels
Iron is needed to produce hemoglobin, a protein that carries oxygen through your blood. Normalizing your iron levels can help reduce fatigue and improve your overall energy.
Better cognitive function
Iron helps support neurological function, and restoring levels can improve concentration, memory, and cognitive function. ( 22 )
A healthy pregnancy
Additional iron is needed to support increased blood volume in pregnancy and a growing baby. Iron supplements can help prevent anemia during pregnancy.
Mood improvements
Along with the other neurological effects of low iron, some people may experience depressed moods. Improving iron levels may reduce depressive symptoms. ( 23 )
Healthy hair, skin, and nails
Iron plays a role in maintaining healthy skin, hair, and nails. Hair loss, spoon-shaped nails, and skin abnormalities can all result from iron deficiency anemia. ( 24 , 25 )
How much iron do I need a day?
The amount of iron you need in a day depends on your age and gender. Here are the recommended dietary allowances (RDA) for iron in milligrams (mg), based on gender and age: ( 19 )
- Children, 9-13 : 8 mg
- Boys, 14-18 : 11 mg
- Girls, 14-18 : 15 mg
- Men, 19+ : 8 mg
- Women, 19-50 : 18 mg
- Women, 51 +: 8 mg
- During pregnancy : 27 mg
Many supplements have more than 100% of the RDA for iron because your body cannot absorb all of the iron consumed in supplement form. Amounts up to 20 mg per kilogram of body weight are often tolerated, while doses of 20-60 mg per kilogram are moderately toxic, and doses over 60 mg per kilogram can lead to death related to the collapse of the circulatory system. ( 3 )
FAQs
What is the most effective iron supplement?
The most effective iron supplement is the one you can best tolerate. That said, iron supplements made from iron salts—like ferrous fumarate, sulfate, or gluconate—as well as chelated iron tend to be the most effective at being absorbed, increasing iron levels, and causing the least side effects, depending on the dosage.
Which form of iron is best absorbed?
Heme iron, found in meat, is the most absorbable form of iron, having a 15-30% absorption rate. ( 19 )
What are some signs of iron deficiency?
Signs of iron deficiency include weakness, fatigue, difficulty concentrating, impaired immune function, exercise, or work performance, and poor body temperature regulation. Iron deficiency in pregnancy increases the risk of maternal and infant death, as well as premature birth and low birth weight . ( 19 )
When is the best time to take iron supplements?
The best time to take an iron supplement is on an empty stomach for the highest absorption rate, although taking it with food may help minimize digestive side effects.
What are some side effects of iron supplements?
The most common side effects of iron supplements include nausea, vomiting, gas, constipation or diarrhea, metallic taste, and stomach pains. ( 3 )
These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any diseases.
Our experts
Victoria Burgess, Ph.D., CSCS, CISSN
Victoria Burgess earned her Ph.D. in Health and Human Performance from Concordia University Chicago and holds her NSCA CSCS and Certified Sports Nutritionist (CISSN). She is an adjunct professor in the Human Performance and Nutrition department at Concordia University Chicago & Parker University, where she teaches undergraduate, graduate, and doctoral-level courses.
Joana Neziri, M.S., NASM CPT
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Kelsey Kunik is a registered dietitian with 5+ years of experience writing SEO nutrition and wellness content. She writes editorial and commerce content for several national online publications, such as Eat This!, Healthline, Livestrong.com, and Clean Plates, and have been featured as a nutrition expert in hundreds of published articles in top-tier outlets.