Iron and medications.
Iron is in the Distil supplement database, evidence Grade A. The page below lists every medication we have explicitly assessed it against.
Iron carries oxygen and underpins energy and clear thinking, and low ferritin tracks closely with worse ADHD symptoms and poor stamina. Ferrous bisglycinate is the best-tolerated form, ahead of gluconate and then sulfate, which is the one that tends to upset the gut. The single non-negotiable rule is the blood test: never supplement iron without a confirmed low ferritin or full blood count, because iron overload does real harm and the body has no easy way to shed excess. Evidence is Grade A for correcting deficiency and Grade B for performance, with Konofal 2004 linking low ferritin to ADHD in children and Pasricha 2014 reviewing performance in women. Timing drives most of the interactions. Separate iron from zinc, calcium and magnesium by two hours, from tea, coffee and dairy by one hour, and from antibiotics by two hours. Vitamin C taken alongside markedly improves absorption. Take it with food, and keep it well away from children.
Below are the 13 documented pairs we have explicitly assessed for Iron: 13 amber. The pairs cluster around 2 mechanisms: Absorption interference and Mineral chelation (absorption). Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not listed here is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by medication, and the missing-item form at the bottom of the page routes any uncatalogued medication into our next curation pass.
Documented interactions
Absorption interference
Non-haem iron from supplements absorbs less well in a low-acid stomach, so chronic esomeprazole use reduces iron uptake from a standard ferrous sulphate or ferrous fumarate tablet. Iron bisglycinate is less pH-dependent and a better choice on a long-term PPI. Taking iron in the morning on an empty stomach with vitamin C also helps. Always confirm ferritin is in the deficient range before supplementing iron.
Famotidine reduces stomach acid, and non-haem iron absorbs less well in a low-acid stomach, so it can lower iron uptake from a standard ferrous sulphate or ferrous fumarate tablet. The effect tends to be less marked than with a PPI like omeprazole, because famotidine suppresses acid less completely. Iron bisglycinate is less pH-dependent, and taking iron in the morning on an empty stomach with vitamin C helps. Always confirm ferritin is in the deficient range before supplementing iron.
Non-haem iron from supplements absorbs less well in a low-acid stomach, so chronic lansoprazole use reduces iron uptake from a standard ferrous sulphate or ferrous fumarate tablet. Iron bisglycinate is less pH-dependent and a better choice on a long-term PPI. Taking iron in the morning on an empty stomach with vitamin C also helps. Always confirm ferritin is in the deficient range before supplementing iron.
Non-haem iron from supplements absorbs less well in a low-acid stomach, so chronic omeprazole use reduces iron uptake from a standard ferrous sulphate or ferrous fumarate tablet. Iron bisglycinate is less pH-dependent and a better choice on a long-term PPI. Always confirm ferritin is in the deficient range before supplementing iron.
Non-haem iron from supplements absorbs less well in a low-acid stomach, so chronic pantoprazole use reduces iron uptake from a standard ferrous sulphate or ferrous fumarate tablet. Iron bisglycinate is less pH-dependent and a better choice on a long-term PPI. Taking iron in the morning on an empty stomach with vitamin C also helps. Always confirm ferritin is in the deficient range before supplementing iron.
Mineral chelation (absorption)
Iron binds to alendronic acid in the gut and blocks absorption in the same way calcium does. Take alendronic acid first thing on an empty stomach with plain water, stay upright for 30 minutes, then wait at least two hours before any iron supplement.
Iron binds to ciprofloxacin in the gut and can cut the amount of antibiotic you absorb by more than half, which may let an infection persist. Take ciprofloxacin at least two hours before, or six hours after, any iron supplement.
Iron binds levodopa in the gut and reduces how much you absorb, which can weaken your Parkinson's symptom control. Take your co-beneldopa dose and any iron supplement at least two hours apart. Only take iron if a blood test has confirmed your ferritin is low, as Distil does not recommend iron without confirmed deficiency.
Iron binds levodopa and carbidopa in the gut and reduces how much of each you absorb, which can weaken your Parkinson's symptom control. Take your co-careldopa dose and any iron supplement at least two hours apart. Only take iron if a blood test has confirmed your ferritin is low, as Distil does not recommend iron without confirmed deficiency.
Iron binds to doxycycline in the gut and can seriously reduce how much antibiotic you absorb, which may let an infection persist. Take doxycycline at least two hours before, or six hours after, any iron supplement.
Iron can bind to levothyroxine in the gut and reduce how much you absorb. Separating doses by four hours usually solves it.
Iron can bind to minocycline in the gut and lower how much antibiotic your body absorbs, which may make it less effective. Minocycline is absorbed better than older tetracyclines so the effect is smaller, but it is still worth keeping the two apart: take minocycline at least 2 hours before or 6 hours after your iron supplement.
Iron binds to risedronate in the gut and blocks absorption. Take risedronate first thing on an empty stomach with plain water, stay upright for 30 minutes, then wait at least two hours before any iron supplement.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope. Use the checker below to surface any medication, and submit a missing item if you take something we have not catalogued.
How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
Read the full methodologyWant this checked across everything you take?
This page checks the pairs you enter. The personalised Distil report goes further:
- the same graded, cited interaction check across your whole stack, not just the pairs you thought to type in
- where your current routine may be leaving you short of your goals
- the evidence-backed compounds worth adding, and the ones worth dropping
It's a paid report: £79, or £49 for the first 25 customers. The interactions check is one section of it, and you can read a real one in full before you buy.
See a real sample reportSomething missing?
If a supplement or medication you take isn't in our autocomplete, tell us. We go through what people flag every week and add what's missing.