What is the recommended dose of Iron?

- **RDA (adult males):** 8mg/day - **RDA (adult females, 19-50):** 18mg/day (higher due to menstrual losses) - **RDA (pregnant women):** 27mg/day - **For deficiency treatment:** 1-300mg elemental i...

Is Iron safe to take daily?

Iron is rated "Prescription Interactions" based on clinical evidence. - **Very common (even at small doses):** Constipation, diarrhea, nausea, dark/black stools, abdominal pain, vomiting, heartburn, flatulence - **Less common (tablet formulations):** Upper GI ulceration (esophageal/stomach erosion)

Does Iron interact with any medications?

Iron has 17 known drug interactions, including interactions with Tetracycline antibiotics, Fluoroquinolone antibiotics, Carbamazepine/Cyclosporine. Check with your doctor before combining with prescription medications.

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Ingredient Research

Graded against 173,636 supplements + 177 published clinical interactions, sourced from PubMed, FDA CAERS, openFDA, NIH DSLD

Iron

STRONG EVIDENCEMineralLast updated April 5, 2026

AVELOR SUMMARY

Iron is an essential mineral that carries oxygen in your blood. Unlike most supplements on this list, iron is one you should NOT take unless you're deficient or a healthcare provider recommends it. Our research, from 9 RCTs, 13 meta-analyses, and 107,000+ participants, confirms iron supplementation corrects deficiency and anemia — but excess iron increases oxidative stress and can cause serious organ damage. This is a "test first, supplement second" ingredient.

EVIDENCE GRADES

Risk of Hospitalization for Heart FailureStrong — iron reduces hospitalization in heart failure with iron deficiency

Ferritin increaseModerate

Hemoglobin increaseModerate

Fatigue reductionModerate — in iron-deficient individuals

Exercise capacityModerate — in iron-deficient individuals

WHAT IT DOES

Corrects iron deficiency anemia — Primary indication. Restores hemoglobin and oxygen-carrying capacity.
Reduces fatigue in iron-deficient individuals — Grade B evidence. Only works if you're actually deficient.
Reduces heart failure hospitalizations — Grade A evidence in iron-deficient HF patients.
Supports exercise performance — Grade B evidence, specifically in iron-deficient athletes (common in female athletes).
Does NOT benefit iron-sufficient people — Excess iron increases oxidative stress and may damage organs.

OPTIMAL DOSAGE

RDA (adult males): 8mg/day
RDA (adult females, 19-50): 18mg/day (higher due to menstrual losses)
RDA (pregnant women): 27mg/day
For deficiency treatment: 1-300mg elemental iron/day, divided doses
UL (adults): 45mg/day (based on GI side effects)
Best forms: Ferrous bisglycinate (best tolerated, good absorption), ferrous sulfate (most studied, cheap, more GI effects), ferric maltol (better tolerated)
AVOID taking with: Phytate-rich foods (grains, legumes), dairy/calcium, tea/coffee, eggs
Timing: Best on empty stomach for absorption, but taking with food reduces nausea. Alternate-day dosing may improve absorption and reduce side effects.
KEY: Get tested first. Iron is the one supplement where blind supplementation can cause harm.

Scan a supplement containing Iron

DRUG INTERACTIONS

Tetracycline antibioticsSevere

Mutual absorption reduction

Take tetracyclines 2 hours before or 4 hours after iron.

Fluoroquinolone antibioticsSevere

Reduces antibiotic absorption

Take fluoroquinolones 2 hours before or 4-8 hours after iron.

Carbamazepine/CyclosporineSevere

Reduces drug absorption

Separate administration. Monitor drug levels.

CefdinirSevere

Reduces drug absorption

Separate dosing times.

Integrase inhibitors (dolutegravir)Severe

Reduces drug absorption

Separate by 4+ hours.

LevothyroxineModerate

Reduces drug absorption

Take levothyroxine 2+ hours before iron.

PenicillamineModerate

Reduces drug absorption

Separate administration.

Acid-reducing drugs (PPIs, H2 blockers, antacids)Moderate

Reduces iron absorption

May need higher iron doses or alternate-day dosing.

LevodopaModerate

Reduces drug absorption

Separate by 2+ hours.

CalciumModerate

Reduces iron absorption

Take at separate times if using calcium citrate.

CaptoprilModerate

Reduces drug absorption

Separate by 2+ hours.

MethyldopaModerate

Reduces drug absorption

Separate by 2+ hours.

MagnesiumModerate

Reduces iron absorption

Take at separate times.

Yerba MateModerate

Reduces iron absorption

Don't take iron with yerba mate.

Curcumin/TurmericModerate

Mixed evidence

Monitor iron levels if taking high-dose curcumin.

ZincMinor

Mutual absorption reduction

Take at separate times if concerned.

AcetaminophenMinor

Reduces absorption

No action needed.

SAFETY PROFILE

Side Effects

Very common (even at small doses): Constipation, diarrhea, nausea, dark/black stools, abdominal pain, vomiting, heartburn, flatulence
Less common (tablet formulations): Upper GI ulceration (esophageal/stomach erosion)
IV iron: Infusion reactions (flushing, hives, chest pressure, anaphylaxis), hypophosphatemia
Toxicity (≥20mg/kg body weight): Vomiting, GI bleeding, liver necrosis, multiorgan failure, shock, metabolic acidosis, coma, death. Leading cause of poisoning deaths in children under 6.

Drug Interactions

△ KEY RULE: Iron chelates many drugs in the gut. Take iron at least 2 hours before or 3 hours after medications.

Nutrient Depletions (Drugs That Deplete Iron)

PPIs — prolonged use (1+ years) increases iron deficiency risk
H2 antagonists — associated with increased iron deficiency risk
Calcium channel blockers — one study correlated with iron deficiency in heart failure
Aspirin — associated with iron deficiency anemia (weak evidence)
Grape seed extract — high doses (2,500mg/day) may reduce serum iron

Precautions

Pregnancy: Caution. Supplementation at appropriate doses is safe and often recommended. Severe toxicity (overdose) can cause miscarriage, preterm delivery, and maternal death.
Breastfeeding: Safe. Breast milk iron is tightly regulated and not greatly influenced by supplementation.
Children: HIGH DANGER. Iron toxicity is a leading cause of poisoning deaths in children under 6. Store safely. Toxicity at ≥20mg/kg bodyweight.
Hemochromatosis: AVOID. Genetic disorder causing iron overload → liver cirrhosis, heart disease, cancer.
GI ulcers: Iron tablets can worsen pre-existing ulcers. Use liquid iron or IV if needed.
General population: Do NOT supplement unless deficient. Excess iron increases free radical production, oxidative stress, and potential organ damage.

WADA Status

Not Prohibited. Not on the 2026 WADA list.

WHO SHOULD BE CAREFUL

HOW AVELOR SCORES THIS

Present in proper dose (8-18mg depending on gender, bioavailable form):✅ Green flag — IF the target user needs iron (menstruating women, athletes, deficient individuals)

Present without medical indication:⚠️ Yellow flag — iron should not be supplemented blindly

High dose (>45mg/serving) without medical supervision:🔴 Red flag — exceeds UL, toxicity risk

In a proprietary blend:🔴 Red flag — iron dose MUST be known for safety

Iron oxide form:⚠️ Yellow flag — poorest absorption, often used as colorant not supplement

In a children's product without childproof packaging:🔴 Red flag — leading cause of pediatric poisoning deaths

Combined with antibiotics in same product:🔴 Red flag — chelation reduces antibiotic effectiveness

CLINICAL REFERENCES

Alternate-day iron dosing results in better fractional absorption than daily dosing.

Stoffel NU et al. Iron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split doses.. Lancet Haematol (2017). PMID: 33232588

Single daily dose in the morning maximizes absorption; twice-daily dosing paradoxically reduces total absorption.

Moretti D et al. Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses.. Blood (2015). PMID: 29323692

Comprehensive review of iron deficiency pathophysiology, diagnosis, and treatment — the go-to reference for iron metabolism.

Camaschella C. Iron deficiency.. Blood (2019). PMID: 31447418

Iron deficiency affects >1 billion people globally. Ferritin <30 μg/L is the most useful single test for iron deficiency.

Pasricha SR et al. Iron deficiency.. Lancet (2021). PMID: 32098519

IV iron at discharge reduced heart failure hospitalizations by 26%.

Ponikowski P et al. Ferric carboxymaltose for iron deficiency at discharge after acute heart failure.. Lancet (2020). PMID: 30879237

RELATED RESEARCH

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CalciumCalcium carbonate

Quality Testing Intelligence

Based on independent third-party laboratory analysis

Category pass rate: ~85% pass rate. Form and absorption are more important than label accuracy.

Scan Your Iron Supplement Browse all ingredients

Independently graded against 173,636 indexed supplements with 177 published clinical interactions, sourced from PubMed, FDA CAERS, openFDA, and NIH DSLD | Last updated: April 5, 2026

Not medical advice. Based on published clinical research and systematic reviews.

Iron · interaction landscape

9 flagged

Dangerous

Moderate

Timing

Pre-op

Safety

Iron: Drug Interactions

Use with caution

Moderate interactions. Monitoring, timing separation, or dose adjustment may be required.

Levothyroxine
Iron binds levothyroxine in the gut.
RiskSubtherapeutic thyroid levels.
ActionSeparate by 4 or more hours.
SourceFDA label
Antacids, PPIs, H2 blockers
Reduced stomach acid impairs iron absorption.
RiskIron deficiency persists.
ActionTake iron on an empty stomach or with vitamin C. Separate from antacids by 2 or more hours.
SourceClinical standard
Tetracycline and doxycycline
Iron chelates the antibiotic.
RiskAntibiotic treatment failure.
ActionSeparate by 2 to 3 hours.
SourceFDA label
Fluoroquinolones
Iron chelates the antibiotic.
RiskAntibiotic treatment failure.
ActionTake 2+ hours before or 6+ hours after the antibiotic.
SourceFDA label
Levodopa (Parkinson's)
Iron reduces levodopa absorption.
RiskWorsened Parkinson's symptoms.
ActionSeparate by 2 or more hours.
SourceClinical pharmacology
Methyldopa
Iron reduces absorption.
RiskSubtherapeutic blood pressure control.
ActionSeparate by 2 or more hours.
SourceFDA label

Timing Separation Rules

Levothyroxine4 hours
Tetracycline / fluoroquinolone antibiotics2 to 3 hours
Antacids and PPIs2 hours

Educational information only. This is not medical advice. These statements have not been evaluated by the FDA. Talk to your prescriber before starting, stopping, or combining any supplement with prescription medication.

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Ingredient Research

Graded against 173,636 supplements + 177 published clinical interactions, sourced from PubMed, FDA CAERS, openFDA, NIH DSLD

Iron

STRONG EVIDENCEMineralLast updated April 5, 2026

AVELOR SUMMARY

EVIDENCE GRADES

Risk of Hospitalization for Heart FailureStrong — iron reduces hospitalization in heart failure with iron deficiency

Ferritin increaseModerate

Hemoglobin increaseModerate

Fatigue reductionModerate — in iron-deficient individuals

Exercise capacityModerate — in iron-deficient individuals

WHAT IT DOES

Corrects iron deficiency anemia — Primary indication. Restores hemoglobin and oxygen-carrying capacity.
Reduces fatigue in iron-deficient individuals — Grade B evidence. Only works if you're actually deficient.
Reduces heart failure hospitalizations — Grade A evidence in iron-deficient HF patients.
Supports exercise performance — Grade B evidence, specifically in iron-deficient athletes (common in female athletes).
Does NOT benefit iron-sufficient people — Excess iron increases oxidative stress and may damage organs.

OPTIMAL DOSAGE

RDA (adult males): 8mg/day
RDA (adult females, 19-50): 18mg/day (higher due to menstrual losses)
RDA (pregnant women): 27mg/day
For deficiency treatment: 1-300mg elemental iron/day, divided doses
UL (adults): 45mg/day (based on GI side effects)
Best forms: Ferrous bisglycinate (best tolerated, good absorption), ferrous sulfate (most studied, cheap, more GI effects), ferric maltol (better tolerated)
AVOID taking with: Phytate-rich foods (grains, legumes), dairy/calcium, tea/coffee, eggs
Timing: Best on empty stomach for absorption, but taking with food reduces nausea. Alternate-day dosing may improve absorption and reduce side effects.
KEY: Get tested first. Iron is the one supplement where blind supplementation can cause harm.

Scan a supplement containing Iron

DRUG INTERACTIONS

Tetracycline antibioticsSevere

Mutual absorption reduction

Take tetracyclines 2 hours before or 4 hours after iron.

Fluoroquinolone antibioticsSevere

Reduces antibiotic absorption

Take fluoroquinolones 2 hours before or 4-8 hours after iron.

Carbamazepine/CyclosporineSevere

Reduces drug absorption

Separate administration. Monitor drug levels.

CefdinirSevere

Reduces drug absorption

Separate dosing times.

Integrase inhibitors (dolutegravir)Severe

Reduces drug absorption

Separate by 4+ hours.

LevothyroxineModerate

Reduces drug absorption

Take levothyroxine 2+ hours before iron.

PenicillamineModerate

Reduces drug absorption

Separate administration.

Acid-reducing drugs (PPIs, H2 blockers, antacids)Moderate

Reduces iron absorption

May need higher iron doses or alternate-day dosing.

LevodopaModerate

Reduces drug absorption

Separate by 2+ hours.

CalciumModerate

Reduces iron absorption

Take at separate times if using calcium citrate.

CaptoprilModerate

Reduces drug absorption

Separate by 2+ hours.

MethyldopaModerate

Reduces drug absorption

Separate by 2+ hours.

MagnesiumModerate

Reduces iron absorption

Take at separate times.

Yerba MateModerate

Reduces iron absorption

Don't take iron with yerba mate.

Curcumin/TurmericModerate

Mixed evidence

Monitor iron levels if taking high-dose curcumin.

ZincMinor

Mutual absorption reduction

Take at separate times if concerned.

AcetaminophenMinor

Reduces absorption

No action needed.

SAFETY PROFILE

Side Effects

Very common (even at small doses): Constipation, diarrhea, nausea, dark/black stools, abdominal pain, vomiting, heartburn, flatulence
Less common (tablet formulations): Upper GI ulceration (esophageal/stomach erosion)
IV iron: Infusion reactions (flushing, hives, chest pressure, anaphylaxis), hypophosphatemia
Toxicity (≥20mg/kg body weight): Vomiting, GI bleeding, liver necrosis, multiorgan failure, shock, metabolic acidosis, coma, death. Leading cause of poisoning deaths in children under 6.

Drug Interactions

△ KEY RULE: Iron chelates many drugs in the gut. Take iron at least 2 hours before or 3 hours after medications.

Nutrient Depletions (Drugs That Deplete Iron)

PPIs — prolonged use (1+ years) increases iron deficiency risk
H2 antagonists — associated with increased iron deficiency risk
Calcium channel blockers — one study correlated with iron deficiency in heart failure
Aspirin — associated with iron deficiency anemia (weak evidence)
Grape seed extract — high doses (2,500mg/day) may reduce serum iron

Precautions

Pregnancy: Caution. Supplementation at appropriate doses is safe and often recommended. Severe toxicity (overdose) can cause miscarriage, preterm delivery, and maternal death.
Breastfeeding: Safe. Breast milk iron is tightly regulated and not greatly influenced by supplementation.
Children: HIGH DANGER. Iron toxicity is a leading cause of poisoning deaths in children under 6. Store safely. Toxicity at ≥20mg/kg bodyweight.
Hemochromatosis: AVOID. Genetic disorder causing iron overload → liver cirrhosis, heart disease, cancer.
GI ulcers: Iron tablets can worsen pre-existing ulcers. Use liquid iron or IV if needed.
General population: Do NOT supplement unless deficient. Excess iron increases free radical production, oxidative stress, and potential organ damage.