US RDA
8 to 18 mg daily (higher for menstruating women)
Effective dose
30 to 60 mg daily elemental iron if deficient (get blood work first)
Upper limit
45 mg daily supplemental unless directed by physician
Timing
Every other day, morning, empty stomach if tolerated
With food
Empty stomach ideal but with food if nausea
Bioavailability
Heme iron (animal) > non-heme (plant). Pair with vitamin C for absorption.
Best forms to buy
Ferrous bisglycinate
Gentler on stomach, well absorbed
Ferrous sulfate
Standard, cheap, harsher
Heme iron polypeptide
Best absorbed, more expensive
Signs of deficiency
- · Fatigue
- · Cold hands and feet
- · Pale skin
- · Brittle nails
- · Restless leg syndrome
- · Hair loss
Drug interactions
- · Calcium, coffee, tea reduce absorption
- · Vitamin C enhances absorption
- · Do not take with other minerals
Toxicity
Constipation, nausea. Serious toxicity with overdose (especially in children). Keep locked away.