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Iron is a mineral present in hemoglobin, a protein that transports oxygen from the lungs to the tissues, and myoglobin, another protein that carries and stores oxygen for your muscles.
It’s also essential for brain cell development, physical growth, and hormone synthesis, and it supports muscle metabolism (1).
Iron can be found as heme or non-heme iron. Plants and iron-fortified products only contain non-heme iron, but animal food sources contain both forms of iron. Some of the richest sources of iron include lean meats, seafood, nuts, beans, and leafy greens.
Still, some populations may have inadequate iron intakes, impaired absorption, or increased iron needs. Thus, they may be at risk of iron deficiency, which may lead to fatigue, dizziness, and weakness, among other symptoms (
These populations typically include pregnant women, infants and kids, athletes, people with heavy menstrual bleeding, those with gastrointestinal disorders or cancer, and frequent blood donors.
Fortunately, there are plenty of iron supplements available that can help you restore your iron stores.
This article examines iron supplements based on the following criteria:
- third-party testing and other quality certifications
- the type of iron and its bioavailability, meaning whether it’s easily absorbed
- the presence of nutrients that may enhance or impair absorption
- the dosage and price
Here are the 10 best iron supplements for 2021.
A note on price
General price ranges with dollar signs ($ to $$$) are indicated below. One dollar sign means the product is rather affordable, whereas three dollar signs indicate a higher price range.
Generally, prices range from $0.04–$0.86 per serving, or $10.35–$42.99 per container, though this may vary depending on where you shop.
- $ = under $0.20 per serving
- $$ = $0.20–$0.40 per serving
- $$$ = over $0.40 per serving
Nature Made boasts 65 mg of iron per capsule — 361% of the Daily Value (DV) for iron — or the equivalent of 325 mg of ferrous sulfate.
Ferrous sulfate is a common form of supplemental iron with high solubility, meaning that it releases iron ions faster, making it easier to absorb (
The product is also verified by the United States Pharmacopeia (USP), a third-party organization that tests quality, including a product’s purity, potency, and performance.
As one of the most reputable supplement brands, Thorne Iron Bisglycinate was sure to be found on this list.
This supplement packs 25 mg of iron bisglycinate per capsule, another form of iron claimed to have increased bioavailability and efficacy, as well as fewer gastrointestinal side effects (4,
The product is also NSF Certified for Sport, meaning that it’s free of prohibited substances per most sports organizations, making it safe for athletes.
Additionally, Thorne’s facilities are verified by multiple international third-party organizations, including Australia’s Therapeutic Goods Administration (TGA) — the toughest regulatory agency in the world.
As its name suggests, this supplement provides iron in the form of ferrous gluconate, another popular supplemental iron form that’s easily absorbed.
The bottle contains 100 capsules, each packing 65 mg of iron.
All of Mason Natural’s supplements are manufactured following the current Good Manufacturing Practice (cGMP) guidelines enforced by the Food and Drug Administration (FDA).
Zahler Iron Complex provides 25 mg of iron bisglycinate per capsule — or 139% of the DV — plus 60 mg of vitamin C.
Vitamin C is often added to iron supplements because it enhances iron absorption. In fact, it’s the only iron absorption enhancer in vegetarian diets (
The product is produced in a cGMP-certified facility. It’s also kosher, gluten-, soy-, and dairy-free, as well as vegetarian friendly.
Garden of Life Vitamin Code Raw Iron provides 22 mg of whole food iron and 25 mg of vitamin C.
The term whole food iron means that it comes from raw-food-created nutrients. It also indicates that the supplement is produced without high heat, synthetic binders or fillers, artificial flavors, sweeteners, colors, or additives.
Additionally, the product contains an organic fruit and vegetable blend, as well as a probiotic and enzyme blend, to support digestion.
All of Garden of Life products are manufactured in an FDA-certified facility, and this supplement is also certified vegan, non-GMO, kosher, raw, and gluten-free.
NOW supplements are known for offering high quality products at affordable prices.
This one provides 18 mg of iron per capsule in the form of iron bisglycinate, and each bottle packs 120 capsules.
Furthermore, the product is certified by Underwriters Laboratories (UL), a third-party testing organization that ensures that a product meets rigorous safety standards.
It’s also certified kosher, halal, and non-GMO.
Along with providing 9 mg of iron, this supplement packs 30 mg of vitamin C and multiple fermented probiotics and enzymes blends, which they list as “ferment media.”
The supplement’s fermented ingredients are meant to support digestion and ward off gastrointestinal side effects, allowing you to take it even on an empty stomach.
Its iron comes in the form of ferrous fumarate, the least toxic form of iron that’s already attributed with fewer gastrointestinal side effects due to its slow release rate (
What’s more, this product is certified NSF gluten-free, international certification services, Inc. (ICS) organic, kosher, and non-GMO, as well as manufactured by a certified B Corporation. B Corporations meet high standards to balance profit and purpose.
Unlike the other supplements on this list, MegaFood Blood Builder provides 26 mg of iron in the form of iron-enriched yeast — more specifically, S. cerevisiae.
S. cerevisiae is a valuable food supplement that provides protein and vitamins in the diet. Since it thrives in high iron environments, it’s an effective iron-uptake-supporting agent (
What’s more, this supplement also provides 60 mg of vitamin C for improved absorption.
Furthermore, all MegaFood supplements are verified by six third-party testing organizations. The company’s certifications include B Corporation, NSF gluten-free, non-GMO, kosher, vegan, and Glyphosate Residue Free.
Liquid supplements offer a tasty alternative for those who dislike capsules.
Salus-Haus Floradix Iron + Herbs provides 10 mg of iron and several fruit juice concentrates per 2-teaspoon (10-mL) serving.
The iron comes in the form of ferrous gluconate. It also includes some vitamins from the vitamin B complex, which promote the growth of healthy red blood cells (
Finally, all Salus-Haus products are manufactured according to the cGMP guidelines for quality control.
Much like liquid supplements, gummy supplements are a convenient and tasty way to take your vitamins and minerals.
Vitamin Friends Adult Vegan Iron Gummies provide 10 mg of elemental iron per gummy, along with 30 mg of vitamin C.
The brand prides itself on being one of the few supplement brands certified top 8 allergen-free, as all of its products are manufactured in an allergen-free facility.
Additionally, its products are certified vegan, organic, kosher, and non-GMO, as well as manufactured in an NSF-, cGMP-, and FDA-registered facility.
What’s more, they have a wide range of children’s supplements, including Kids Organic Vegan Iron Gummies, which provide 5 grams of elemental iron per gummy.
However, keep in mind that you should only give your child a supplement if their healthcare provider recommends it.
Shop for Kids Iron Vegan Gummies online.
There are a few factors you should take into account when choosing an iron supplement.
First, there’s the type of iron. The most popular ones are ferrous and ferric iron salts, which include ferric sulfate, ferrous gluconate, ferrous sulfate, and ferric citrate.
Due to its higher solubility, ferrous iron tends to be more bioavailable than ferric iron, meaning that it’s more easily absorbed (1).
These may have fewer gastrointestinal side effects than the ones above.
Second, you should look for added nutrients that may impair or promote iron absorption. For instance, calcium is a strong iron intake inhibitor, whereas vitamin C is a potent enhancer (
Third, check for high quality brands that use third-party quality testing, such as those certified by organizations like UL, USP, and NSF International.
Lastly, be sure to consider the dosage and check for allergens.
The recommended daily amount of iron for adults is 8 mg for men and 18 mg for women. It increases to 27 mg for pregnant women. As for kids, those 1–3 years old need 7 mg per day, and the recommended amount rises to 10 mg per day for those 4–8 years old.
However, the recommendation for vegans and vegetarians is 1.8 times higher, as the iron from plant-based foods is less bioavailable than the iron from animal-based foods (1).
As for allergens, check the label to avoid unwanted ingredients, or opt for a supplement that’s certified kosher, vegan, or gluten-free.
Useful supplement shopping guides
Check out these two articles to help make supplement shopping a breeze:
Whether iron comes from foods or supplements, it can interact with certain medications.
For example, it may reduce the absorption of drugs used to treat Parkinson’s disease and lower the efficacy of levothyroxine — a common drug used to treat hypothyroidism, goiter, and thyroid cancer (1).
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, as they lower the secretion of gastric acid, which plays a key role in iron uptake (1,
Additionally, iron supplements that provide 9 mg per pound (20 mg per kg) of body weight may cause nausea, constipation, abdominal pain, and vomiting (1).
Therefore, it’s recommended to take your supplement with a meal.
Finally, note that it’s always best to consult your healthcare provider before taking an iron supplement.
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, supplementing may sometimes become necessary and help you reach your daily iron needs.
Many types of iron supplements provide the mineral in varying doses and forms.
Remember to consult your healthcare provider before you purchase any supplement, and consider the factors mentioned above to make sure you choose one of high quality.