The short answer
Each dose of iron makes your liver release hepcidin, which partly closes the gut door for about a day. Studies in iron-depleted women found that iron taken on alternate days was absorbed better per dose, with fewer stomach complaints. Agree any schedule with your doctor.
Hepcidin is the hormone that controls how much iron gets in. It rises after an iron dose and stays up long enough that a dose the next morning mostly passes straight through. Skip a day and the next dose finds the door open again.
What the studies found
In iron-depleted women, doses on consecutive days raised hepcidin and lowered absorption from the next day's dose. When the same doses were given on alternate days, the share absorbed from each dose was higher. Researchers have suggested alternate-day schedules as a way to get more from each dose with fewer side effects.
Ask your doctor whether an alternate-day schedule suits you.
Double up after a missed day. Carry on with the next planned dose.
Period week
Once ferritin is at goal, The Iron Guide's maintenance plan uses period week: iron every other day on days 1 to 7 of the cycle, about 3 to 4 doses, to put back iron as it is lost. Your recheck decides whether that is enough.
Your dose and schedule come from your doctor. Some situations, such as pregnancy, anaemia or a planned operation, need a different plan.
A real page from The Iron GuideWhy every other day, from the guide's supplements chapter.See more pagesQuestions
Is every other day slower?
Per dose it is more efficient. Over the same weeks you take fewer doses, so ask your doctor how long your course should run.
Does it help with side effects?
Fewer doses usually means fewer stomach complaints, which helps many people stay on a course.
Sources
- 1.Moretti D. et al. Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses in iron-depleted young women. Blood, 2015
- 2.Stoffel N.U. et al. Iron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split dosing in iron-depleted women. Lancet Haematology, 2017
- 3.Stoffel N.U. et al. Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women. Haematologica, 2020
- 4.The Iron Guide, part 6: Taking iron well
This page has not been reviewed by a clinician yet. Read it as general education, and take your own results to your doctor.
Educational, not medical advice. ferritin.ai does not diagnose or treat any condition, and it never sets a dose. Talk to your doctor about your own results.