Best Iron Bisglycinate Supplements

Iron bisglycinate represents a breakthrough in iron supplementation, offering superior absorption and gentleness compared to traditional iron forms. This chelated form of iron binds to amino acids, allowing it to bypass the digestive irritation that plagues conventional iron supplements while delivering up to 4 times better bioavailability. Whether you’re dealing with iron deficiency, supporting pregnancy needs, or simply maintaining optimal iron levels, iron bisglycinate provides an effective solution without the constipation and nausea typically associated with iron supplementation.

Our Top Picks at a Glance

• Best Overall: Thorne Iron Bisglycinate — NSF certified with pharmaceutical-grade quality
• Best Value: Nutricost Iron Bisglycinate — 240 capsules for extended supply
• Best Premium: Pure Encapsulations Iron-C — Highly bioavailable with vitamin C

Quick Comparison

Product	Key Ingredients	Form	Servings	Best For
Thorne Iron Bisglycinate	25mg Ferrochel	Capsules	60	Quality and purity
Nutricost Iron Bisglycinate	25mg chelated iron	Capsules	120	Budget shoppers
Vegepower Iron Bisglycinate	30mg + vitamins	Capsules	60	Comprehensive support
Igennus Clean Iron	20mg + vitamin C	Tablets	180	Targeted release
Doctor’s Recipes Iron	36mg + B vitamins	Capsules	60	Energy support
Best Naturals Iron	25mg bisglycinate	Tablets	180	Long-term supply
Naked Iron	65mg high potency	Capsules	60	Iron deficiency

1. Thorne Iron Bisglycinate — Best Overall

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Thorne’s Iron Bisglycinate stands as the gold standard in iron supplementation, featuring 25mg of elemental iron in the highly bioavailable Ferrochel form with NSF Certified for Sport designation.

This pharmaceutical-grade supplement delivers iron in its most absorbable and gentle form, utilizing Ferrochel ferrous bisglycinate chelate that’s clinically proven to minimize gastrointestinal side effects. Thorne’s commitment to quality is evident through their NSF Certification for Sport, which ensures the product is free of banned substances and safe for competitive athletes. The supplement provides 139% of the daily value for iron, making it highly effective for addressing low iron stores without the constipation and nausea typical of other iron forms.

What We Like

• NSF Certified for Sport ensures purity and absence of banned substances
• Non-constipating Ferrochel form with superior absorption
• Free from unnecessary fillers including lactose and magnesium stearate

What Could Be Better

• Premium pricing reflects pharmaceutical-grade quality
• Some users may need higher doses for severe deficiency

Bottom Line: Thorne delivers uncompromising quality backed by rigorous third-party testing, making it the top choice for those who prioritize purity and efficacy.

2. Nutricost Iron Bisglycinate — Best Value

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Nutricost delivers exceptional value with 120 capsules of 25mg iron bisglycinate, providing a four-month supply at a budget-friendly price point.

This supplement contains 25mg of iron from Ferrochel ferrous bisglycinate chelate per serving, matching the potency of premium brands while offering double the quantity. Nutricost maintains high quality standards with non-GMO and gluten-free formulation, and each batch undergoes testing by independent ISO-accredited laboratories. The company’s USA-based operations and GMP-compliant manufacturing ensure consistent quality batch after batch.

What We Like

• Extended 120-capsule supply provides excellent value
• Third-party tested by ISO-accredited labs for quality assurance
• Simple, clean formula without unnecessary additives

What Could Be Better

• Lacks additional supporting nutrients like vitamin C
• Bottle design may allow capsules to settle densely

Bottom Line: An outstanding option for budget-conscious consumers who want quality iron bisglycinate without premium pricing.

3. Vegepower Iron Bisglycinate — Best Comprehensive Formula

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Vegepower elevates iron supplementation by combining 30mg of iron bisglycinate with synergistic nutrients including vitamin C, B12, folic acid, and zinc for comprehensive blood health support.

This thoughtfully formulated supplement goes beyond simple iron replacement by including key cofactors that enhance iron absorption and red blood cell production. The vitamin C component, provided as magnesium L-ascorbate, significantly boosts iron uptake while being gentle on the stomach. The addition of methylcobalamin B12, folate, and zinc creates a complete formula that supports energy levels, reduces fatigue, and strengthens immune function.

What We Like

• Synergistic blend of nutrients enhances iron absorption and utilization
• 30mg iron dose provides robust support without excessive potency
• Certified vegan, gluten-free, and non-GMO for dietary flexibility

What Could Be Better

• Multiple active ingredients increase capsule size slightly
• May provide more nutrients than needed if supplementing elsewhere

Bottom Line: Perfect for those seeking an all-in-one solution that addresses iron deficiency while supporting overall blood health and energy.

4. Igennus Clean Iron — Best for Targeted Release

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Igennus employs innovative targeted release technology to deliver 20mg of iron bisglycinate directly to the small intestine, maximizing absorption while minimizing gastric irritation.

This UK-manufactured supplement stands out for its sophisticated delivery system that protects the iron until it reaches the small intestine where absorption is optimal. The chelated bisglycinate form is absorbed up to 4 times better than ferrous sulfate, and the addition of vitamin C further enhances uptake. With 180 tablets providing a six-month supply, Igennus offers exceptional value alongside superior technology.

What We Like

• Targeted release technology ensures delivery to optimal absorption site
• Six-month supply in one bottle provides convenience and value
• Hypoallergenic formula free from problematic fillers

What Could Be Better

• 20mg dose may be insufficient for severe deficiency cases
• Tablet form may be less convenient than capsules for some users

Bottom Line: An innovative option for those seeking cutting-edge absorption technology combined with long-term supply convenience.

5. Doctor’s Recipes Iron — Best for Energy Support

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Doctor’s Recipes formulates a powerful iron complex with 36mg of ferrous bisglycinate alongside bioactive forms of B vitamins specifically chosen to combat fatigue and support energy production.

This comprehensive formula provides more than just iron replacement, incorporating 5mg of vitamin B6 as pyridoxal 5′-phosphate, 667mcg DFE of folate as L-5-MTHF, and 30mcg of methylcobalamin B12. These bioactive vitamin forms require no conversion by the body, making them immediately available for red blood cell formation and energy metabolism. The addition of 30mg of vitamin C further enhances iron absorption while providing antioxidant support.

What We Like

• Bioactive vitamin forms provide superior bioavailability
• 36mg iron dose effectively addresses moderate to severe deficiency
• Comprehensive formula targets multiple aspects of energy and blood health

What Could Be Better

• Higher iron content may be excessive for mild deficiency
• Premium formulation comes at higher price point

Bottom Line: An excellent choice for those experiencing significant fatigue alongside iron deficiency who need comprehensive nutritional support.

6. Best Naturals Iron — Best Long-Term Supply

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Best Naturals provides an impressive 180-tablet supply of 25mg iron bisglycinate, offering six months of gentle, non-constipating iron supplementation at an economical price.

This straightforward supplement focuses on delivering pure iron bisglycinate without unnecessary additions, making it ideal for those who prefer simple formulations or are already taking other supplements. The tablets are designed to be gentle on the stomach while providing consistent iron support. Best Naturals’ commitment to quality is reflected in their use of pharmaceutical-grade ingredients and rigorous manufacturing standards.

What We Like

• 180-tablet bottle eliminates frequent reordering
• Non-constipating formula suitable for sensitive digestive systems
• Simple formulation works well with other supplements

What Could Be Better

• Tablet form may be harder to swallow than capsules
• Contains no additional absorption-enhancing nutrients

Bottom Line: A practical choice for maintaining iron levels long-term without the hassle of monthly reordering.

7. Naked Iron — Best for High Potency

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Naked Iron delivers a robust 65mg of elemental iron from 325mg of ferrous bisglycinate, providing powerful support for significant iron deficiency while maintaining better tolerability than ferrous sulfate.

This high-potency formula is specifically designed for those with diagnosed iron deficiency or increased iron needs, such as pregnant women or those recovering from blood loss. Despite the high dose, the ferrous bisglycinate form ensures better absorption and fewer side effects than equivalent doses of ferrous sulfate. The vegan, GMO-free, and gluten-free formulation accommodates various dietary restrictions while delivering therapeutic iron levels.

What We Like

• High 65mg dose effectively addresses severe iron deficiency
• Better absorbed and tolerated than equivalent ferrous sulfate doses
• Vegan-friendly formula suitable for plant-based diets

What Could Be Better

• High potency may cause mild effects in iron-sufficient individuals
• Requires more careful dosing supervision than lower-dose options

Bottom Line: The ideal solution for those with significant iron deficiency who need therapeutic doses without the harsh side effects of traditional high-potency iron.

How to Choose

Iron dosage is the most critical factor in selecting the right supplement for your needs. For maintenance of normal iron levels, 18-25mg of elemental iron daily is typically sufficient. If you’re addressing mild deficiency, 25-36mg may be appropriate, while moderate to severe deficiency often requires 45-65mg or higher under medical supervision. Keep in mind that iron bisglycinate’s superior absorption means you may need less than you would with other iron forms.

Additional ingredients can significantly enhance iron supplementation effectiveness. Vitamin C is perhaps the most important companion nutrient, as it can increase iron absorption by up to 30%. B vitamins, particularly B12 and folate, support red blood cell production and work synergistically with iron. Some formulas include zinc, copper, or other minerals that play supporting roles in iron metabolism. Consider whether you want a comprehensive formula or prefer to take iron separately and customize other nutrients independently.

Form and delivery mechanism affect both convenience and absorption. Capsules are generally easier to swallow and digest, while tablets may be more shelf-stable and economical. Some advanced formulations use targeted release technology to deliver iron specifically to the small intestine where absorption is optimal. The physical form of iron bisglycinate itself matters too—look for Ferrochel, which is the clinically studied and patented form that ensures consistent quality and absorption.

Quality certifications provide assurance of purity and potency. Third-party testing by organizations like NSF, USP, or independent ISO-accredited laboratories verifies that supplements contain what they claim without contaminants. GMP (Good Manufacturing Practice) certification ensures proper manufacturing processes. For those with dietary restrictions, certifications like vegan, non-GMO, and gluten-free are important considerations that shouldn’t be overlooked.

Benefits

Iron bisglycinate provides superior absorption compared to traditional iron forms, with studies showing bioavailability up to 4 times higher than ferrous sulfate. This chelated form binds iron to the amino acid glycine, creating a stable complex that’s easily recognized and absorbed by intestinal cells. The enhanced absorption means you can achieve therapeutic iron levels with lower doses, reducing the risk of side effects while maximizing effectiveness. This efficiency makes iron bisglycinate particularly valuable for those who struggle to maintain adequate iron levels despite supplementation.

The gentleness of iron bisglycinate on the digestive system represents a breakthrough for iron supplementation. Traditional iron supplements like ferrous sulfate are notorious for causing constipation, nausea, stomach cramps, and dark stools. Iron bisglycinate largely avoids these problems because its chelated structure protects it from interacting with other compounds in the digestive tract that trigger irritation. Most users report being able to take iron bisglycinate on an empty stomach if necessary, though taking it with food can further enhance tolerance.

Supporting red blood cell production is iron’s primary function, and adequate iron levels are essential for preventing and treating iron deficiency anemia. Iron is a critical component of hemoglobin, the protein in red blood cells that carries oxygen throughout your body. Without sufficient iron, your body cannot produce enough healthy red blood cells, leading to fatigue, weakness, shortness of breath, and impaired cognitive function. Iron bisglycinate effectively restores iron stores, allowing your body to normalize red blood cell production and reverse anemia symptoms.

Beyond addressing deficiency, optimal iron levels support energy production, immune function, cognitive performance, and overall vitality. Iron plays roles in cellular energy production, neurotransmitter synthesis, and immune cell function. Maintaining healthy iron status can improve exercise performance, reduce fatigue, enhance mental clarity, and support a robust immune response. For pregnant women, adequate iron is crucial for fetal development and preventing complications. Iron bisglycinate provides these benefits while being gentle enough for long-term maintenance supplementation.

Frequently Asked Questions

Is iron bisglycinate better than ferrous sulfate?

Yes, iron bisglycinate is generally superior to ferrous sulfate in both absorption and tolerability. Research shows that iron bisglycinate can be absorbed up to 4 times more efficiently than ferrous sulfate, meaning you can achieve the same results with lower doses. More importantly, the chelated structure of bisglycinate dramatically reduces gastrointestinal side effects like constipation, nausea, and stomach upset that commonly occur with ferrous sulfate. This makes iron bisglycinate the preferred choice for most people requiring iron supplementation.

How much iron bisglycinate should I take daily?

The optimal dose of iron bisglycinate depends on your iron status and needs. For general maintenance, 18-25mg of elemental iron daily is typically sufficient for most adults. Those with mild deficiency may benefit from 25-36mg daily, while moderate to severe deficiency might require 45-65mg or more under medical supervision. Because iron bisglycinate is better absorbed than other forms, you may need less than you would with ferrous sulfate. Always consult with a healthcare provider to determine the right dose for your specific situation.

When is the best time to take iron bisglycinate?

Iron bisglycinate is best taken on an empty stomach, ideally one hour before meals or two hours after, for maximum absorption. However, unlike other iron forms, iron bisglycinate is gentle enough that you can take it with food if necessary without significantly compromising absorption. Some people prefer taking it with breakfast or dinner to avoid forgetting, which is better than not taking it at all. Avoid taking iron with calcium supplements, dairy products, coffee, or tea, as these can interfere with absorption.

Can iron bisglycinate cause constipation?

Iron bisglycinate causes significantly less constipation than traditional iron forms like ferrous sulfate or ferrous gluconate. The chelated structure protects the iron from interactions in the digestive tract that typically cause constipation and other gastrointestinal side effects. While some individuals with extremely sensitive systems may still experience mild digestive changes, the vast majority of users tolerate iron bisglycinate without constipation. This makes it particularly suitable for those who have struggled with constipation from other iron supplements.

How long does it take for iron bisglycinate to work?

You may begin noticing improvements in energy and fatigue within 1-2 weeks of starting iron bisglycinate supplementation, but significant changes in iron stores typically take 2-3 months. Red blood cell turnover occurs over approximately 120 days, so full correction of iron deficiency anemia requires consistent supplementation for at least 3-6 months. Blood tests can track your progress, with ferritin levels usually showing improvement within 4-8 weeks. Continue supplementation as directed even after symptoms improve to fully replenish iron stores.

Should I take vitamin C with iron bisglycinate?

While vitamin C can enhance iron absorption by up to 30%, iron bisglycinate is already highly bioavailable on its own. Many iron bisglycinate supplements include vitamin C in their formulation, which provides additional benefit. If your supplement doesn’t contain vitamin C, taking it alongside orange juice or a vitamin C supplement can further improve absorption. However, iron bisglycinate absorbs well enough that vitamin C, while beneficial, isn’t as critical as it is with less bioavailable iron forms like ferrous sulfate.

Can I take iron bisglycinate during pregnancy?

Yes, iron bisglycinate is safe and often recommended during pregnancy due to its gentle nature and superior absorption. Pregnant women have significantly increased iron needs to support fetal development and increased blood volume, and many prenatal vitamins don’t provide sufficient iron. Iron bisglycinate’s reduced side effects make it more tolerable during pregnancy when digestive sensitivity is already heightened. However, always consult your healthcare provider about appropriate iron supplementation and dosing during pregnancy, especially if you have known iron deficiency.

Will iron bisglycinate cause dark or black stools?

Iron bisglycinate may cause some darkening of stools, but typically less than other iron forms. The chelated structure means more iron is absorbed and less passes through the digestive tract unabsorbed, which is what causes dramatic stool darkening with traditional iron supplements. While some users notice slightly darker stools, the effect is usually mild and not the alarming black color common with ferrous sulfate. This is a harmless side effect and doesn’t indicate any problem with the supplement or your health.

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