Iron

Also known as: Fe, Iron ion, Ferrous, Ferric, Ferrous bisglycinate

Grade A

💊 18-45mg daily when deficient🎯 11 primary uses🔗 1 synergy⚠️ Review warnings

Overview

Essential for oxygen transport and immune cell function, but excess can feed pathogens. Important to test before supplementing.

Primary Uses

Hair lossHair growthFerritin supportEnergyOxygen transportFatigueAnemia preventionImmune cell functionAnemia treatmentImmune functionCognitive function

Compare Forms

8 forms

Different chemical forms vary in absorption, side effects, and best use cases. Higher bioavailability scores indicate better absorption.

Iron Bisglycinate

HIGH 100

Iron chelated with glycine (Ferrochel)

Best for:Iron deficiencySensitive stomachsPregnancy

💡 Excellent absorption. Dramatically reduced GI side effects.

✅ Pros

• Best tolerated
• High absorption
• No constipation
• No nausea

⚠️ Cons

• More expensive
• Lower elemental iron per pill

📝 Ferrochel brand - best choice for most people

Iron Glycinate

HIGH 100

Iron chelated with glycine

Best for:Iron deficiencyGeneral supplementation

💡 Excellent absorption with minimal side effects

✅ Pros

• Great absorption
• Gentle
• Well-tolerated

⚠️ Cons

• Higher cost

📝 Same as bisglycinate

Ferrous Fumarate

HIGH 85

Iron salt with fumaric acid

Best for:Iron deficiencyHigher dose needs

💡 Good absorption. High elemental iron content.

✅ Pros

• High elemental iron
• Effective
• Reasonably priced

⚠️ Cons

• Can cause constipation
• GI upset possible

📝 Good option if glycinate too expensive

Ferrous Gluconate

GOOD 80

Iron salt with gluconic acid

Best for:Mild iron deficiencySensitive stomachs

💡 Good absorption. Gentler than sulfate.

✅ Pros

• Better tolerated than sulfate
• Reasonable absorption

⚠️ Cons

• Lower elemental iron

📝 Middle ground option

Carbonyl Iron

GOOD 75

Highly purified metallic iron

Best for:Those who need pure ironLower toxicity risk

💡 Slow, sustained absorption. Very low toxicity risk.

✅ Pros

• Low toxicity risk
• Slow release
• Pure form

⚠️ Cons

• Slower to raise levels
• May need higher doses

📝 Safest form - low overdose risk

Ferrous Sulfate

GOOD 70

Most common prescription iron form

Best for:Medical treatment of anemiaWhen prescribed

💡 Good absorption but significant GI side effects

✅ Pros

• Inexpensive
• Widely available
• Effective

⚠️ Cons

• Constipation
• Nausea
• Dark stools
• GI upset common

📝 Common but poorly tolerated - try glycinate first

Ferric Citrate

GOOD 70

Ferric iron with citric acid

Best for:Kidney disease patientsPhosphate binding

💡 Moderate absorption. Also binds phosphate.

✅ Pros

• Phosphate binding for kidney patients

⚠️ Cons

• Lower absorption than ferrous forms

📝 Mainly for kidney disease (Auryxia)

Ferric Iron

LOW 55

Oxidized (Fe3+) form of iron

Best for:Specific medical uses

💡 Poor absorption - must be reduced to ferrous form

✅ Pros

• Less reactive

⚠️ Cons

• Poor absorption
• Less effective

📝 Ferrous (Fe2+) forms preferred

Dosage

Typical range

18-45mg daily when deficient

Timing

Empty stomach or with vitamin C

With food

Optional, may reduce absorption

Dose Tiers

RDA / DV

8-18 mg

Moderate

18-30 mg

Therapeutic

60-200 mg elemental

Upper Limit

45 mg

Duration

Until levels normalize

Special Populations

Women, vegetarians

Mechanism of Action

• Hemoglobin component
• Myoglobin in muscles
• Electron transport chain
• Enzyme cofactor

Evidence Quality

Evidence Grade A

Essential mineral critical for oxygen transport

Safety & Contraindications

Serious Warnings

• Toxicity at high doses
• Hemochromatosis

Contraindications

• Hemochromatosis
• Iron overload

Common Side Effects

• Constipation
• Nausea
• Dark stools

Pregnancy & Breastfeeding

Often needed

Liver & Kidney Notes

Test levels first

Interactions

💊 Medications

• Separate from thyroid meds
• Antacids reduce absorption

🧪 Supplements

• Vitamin C enhances
• Calcium inhibits

🍽️ Food & Alcohol

• Meat best source

Stacking & Synergies

Pairs Well With

Vitamin C

Avoid Combining With

CalciumZincCoffee/tea

Best Goal Synergies

EnergyAnemia

Buying Guide

What to Look For

• Gentle form like bisglycinate

Standardization Markers

Elemental iron stated

Adulteration risk

Low

Practical Notes

• Test ferritin before supplementing
• Target ferritin 70+ for hair
• ALWAYS test before supplementing
• Bisglycinate is gentlest form
• Don't supplement if not deficient
• Bisglycinate gentlest on stomach
• Test levels before supplementing
• Bisglycinate gentlest form

Frequently Asked About Iron

How much Iron should I take?

The typical effective range is 18-30 mg. Individual needs vary based on age, body weight, diet, and goals — start at the lower end and adjust based on response. Always consult a healthcare provider before starting a new supplement.

When is the best time to take Iron?

Empty stomach or with vitamin C. Consistency matters more than perfect timing — pick a daily anchor (e.g. with breakfast or before bed) and stick with it.

Should I take Iron with food?

Optional, may reduce absorption.

What is the best form of Iron?

Iron Bisglycinate is generally the best-absorbed form (Iron chelated with glycine (Ferrochel)). Cheaper forms exist but often deliver less usable Iron per dose.

Does Iron interact with medications?

Yes — known interactions include Separate from thyroid meds and Antacids reduce absorption. If you take any prescription medication, talk to your doctor or pharmacist before starting Iron.

What does Iron pair well with?

Iron stacks well with Vitamin C — these combinations either improve absorption or work synergistically toward common goals.

Who should not take Iron?

Iron should be avoided or used with caution by people with Hemochromatosis and Iron overload. Pregnant or breastfeeding women should consult a healthcare provider before use.

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Related Guides

In-depth guides covering Iron — protocols, comparisons, and use cases.

Educational content based on published research and our scoring methodology. Not medical advice — consult a qualified healthcare provider before starting, stopping, or changing supplements, especially if you take medications, are pregnant, or have a medical condition.