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Interaction Checker

Check interactions

Add your supplements, foods, meals — and any medications you take — to see how they interact. Findings are grouped by severity: what to avoid, what needs care or timing, and what actually works better together.

Basic Prenatal

Add more (1/12)

Avoid

3 · Don't combine without medical guidance
Avoid
Vitamin KWarfarin (Coumadin)

Vitamin K directly counteracts warfarin — it can restore clotting and raise clot risk.

Why: Vitamin K is the antidote to warfarin; it regenerates the clotting factors warfarin suppresses.

Do not start/stop vitamin K without your prescriber; keep intake consistent and monitor INR.

Curated
Avoid
Vitamin KAcenocoumarol

Reduces anticoagulant effect

Why: Same as warfarin - vitamin K antagonism

Known interaction
Avoid
Vitamin KPhenprocoumon

Reduces anticoagulant effect

Why: Vitamin K antagonist anticoagulant

Known interaction

Caution

43 · Combine carefully — read the note
Caution
Vitamin EBlood thinners

High-dose vitamin E can increase bleeding risk with blood thinners.

Why: Mild antiplatelet effect at high doses.

Avoid high doses without prescriber guidance.

Curated
Caution
Vitamin KBroad-spectrum antibiotics

Antibiotics kill gut bacteria that produce vitamin K2; may need more K

Why: Reduced intestinal vitamin K synthesis

Known interaction
Caution
Vitamin KCephalosporins

Can cause vitamin K deficiency; bleeding risk

Why: Interfere with vitamin K recycling

Known interaction
Caution
Vitamin KCholestyramine (Questran)

Reduces vitamin K absorption

Why: Binds fat-soluble vitamins in gut

Known interaction
Caution
Vitamin KColestipol

Reduces vitamin K absorption

Why: Bile acid binding

Known interaction
Caution
Vitamin KOrlistat (Alli, Xenical)

Reduces vitamin K absorption

Why: Blocks fat absorption including fat-soluble vitamins

Known interaction
Caution
Vitamin KHigh-dose Vitamin E

High vitamin E may interfere with vitamin K function

Why: Competitive inhibition of vitamin K-dependent clotting

Known interaction
Caution
Vitamin KMineral oil

Reduces vitamin K absorption

Why: Fat-soluble vitamin binding

Known interaction
Caution
BoronNone significant

Boron: None significant

Known interaction
Caution
CalciumSeparate from thyroid meds

Calcium: Separate from thyroid meds

Known interaction
Caution
CalciumAntibiotics

Calcium: Antibiotics

Known interaction
Caution
Choline (Various Forms)May interact with anticholinergics

Choline (Various Forms): May interact with anticholinergics

Known interaction
Caution
Chromium PicolinateMay enhance diabetes meds

Chromium Picolinate: May enhance diabetes meds

Known interaction
Caution
CopperPenicillamine, zinc, antacids reduce absorption

Copper: Penicillamine, zinc, antacids reduce absorption

Known interaction
Caution
IodineThyroid medications

Iodine: Thyroid medications

Known interaction
Caution
IronSeparate from thyroid meds

Iron: Separate from thyroid meds

Known interaction
Caution
IronAntacids reduce absorption

Iron: Antacids reduce absorption

Known interaction
Caution
MagnesiumSeparate from antibiotics

Magnesium: Separate from antibiotics

Known interaction
Caution
ManganeseNone significant

Manganese: None significant

Known interaction
Caution
Vitamin ARetinoids

Vitamin A: Retinoids

Known interaction
Caution
Vitamin B1 (Thiamine)Loop diuretics deplete

Vitamin B1 (Thiamine): Loop diuretics deplete

Known interaction
Caution
Vitamin B12 (Cobalamin)Metformin reduces absorption

Vitamin B12 (Cobalamin): Metformin reduces absorption

Known interaction
Caution
Vitamin B12 (Cobalamin)PPIs reduce absorption

Vitamin B12 (Cobalamin): PPIs reduce absorption

Known interaction
Caution
Vitamin B2 (Riboflavin)None significant

Vitamin B2 (Riboflavin): None significant

Known interaction
Caution
Niacin (Vitamin B3)Statins (myopathy risk)

Niacin (Vitamin B3): Statins (myopathy risk)

Known interaction
Caution
Niacin (Vitamin B3)Blood thinners

Niacin (Vitamin B3): Blood thinners

Known interaction
Caution
Niacin (Vitamin B3)Blood pressure meds

Niacin (Vitamin B3): Blood pressure meds

Known interaction
Caution
Niacin (Vitamin B3)Diabetes meds

Niacin (Vitamin B3): Diabetes meds

Known interaction
Caution
Vitamin B6Levodopa

Vitamin B6: Levodopa

Known interaction
Caution
Vitamin B6Some seizure meds

Vitamin B6: Some seizure meds

Known interaction
Caution
BiotinNone significant

Biotin: None significant

Known interaction
Caution
FolateMethotrexate

Folate: Methotrexate

Known interaction
Caution
FolateSome seizure meds

Folate: Some seizure meds

Known interaction
Caution
Vitamin CMay affect some chemo drugs

Vitamin C: May affect some chemo drugs

Known interaction
Caution
Vitamin DGlucocorticoids (reduced vitamin D effectiveness)

Vitamin D: Glucocorticoids (reduced vitamin D effectiveness)

Known interaction
Caution
Vitamin DAnticonvulsants like phenytoin (increased vitamin D metabolism)

Vitamin D: Anticonvulsants like phenytoin (increased vitamin D metabolism)

Known interaction
Caution
Vitamin DOrlistat (reduced fat-soluble vitamin absorption)

Vitamin D: Orlistat (reduced fat-soluble vitamin absorption)

Known interaction
Caution
Vitamin EStatins

Vitamin E: Statins

Known interaction
Caution
Vitamin KWarfarin - must keep intake consistent

Vitamin K: Warfarin - must keep intake consistent

Known interaction
Caution
SeleniumMay affect thyroid medication needs

Selenium: May affect thyroid medication needs

Known interaction
Caution
ZincSeparate from antibiotics

Zinc: Separate from antibiotics

Known interaction
Caution

Calcium: Iron (separate by 2h)

Stacking note
Caution

Iron: Zinc

Stacking note

Monitor / Timing

12 · Usually fine — mind timing or watch for effects
Monitor / Timing
MagnesiumCertain antibiotics / thyroid / bone drugs

Magnesium can bind these drugs and reduce their absorption.

Why: Cation chelation in the gut.

Separate magnesium from these medications by 2–4 hours.

Curated
Monitor / Timing
CalciumCertain antibiotics / thyroid / bone drugs

Calcium can bind these drugs and reduce their absorption.

Why: Cation chelation in the gut.

Separate calcium from these medications by 2–4 hours.

Curated
Monitor / Timing
IronThyroid / certain antibiotics / Parkinson's drugs

Iron can bind these drugs and reduce their absorption.

Why: Cation chelation in the gut.

Separate iron from these medications by 2–4 hours.

Curated
Monitor / Timing
Vitamin KRivaroxaban (Xarelto)

Minimal interaction - does not depend on vitamin K

Why: Direct factor Xa inhibitor - not vitamin K dependent

Known interaction
Monitor / Timing
Vitamin KApixaban (Eliquis)

Minimal interaction

Why: Direct factor Xa inhibitor

Known interaction
Monitor / Timing
Vitamin KDabigatran (Pradaxa)

Minimal interaction

Why: Direct thrombin inhibitor

Known interaction
Monitor / Timing
Vitamin KHeparin

No significant interaction

Why: Different mechanism

Known interaction
Monitor / Timing
Vitamin KFluoroquinolones

May reduce vitamin K levels

Why: Gut bacteria disruption

Known interaction
Monitor / Timing
Vitamin KColesevelam

May reduce vitamin K absorption

Why: Less effect than older agents

Known interaction
Monitor / Timing
Vitamin KHigh-dose Vitamin A

May interfere with vitamin K absorption

Why: Competition for absorption

Known interaction
Monitor / Timing

Vitamin D: Calcium (synergistic for bone health)

Known interaction
Monitor / Timing

Vitamin D: Magnesium (needed for vitamin D metabolism)

Known interaction

Works well together

23 · Beneficial pairing
Works well together

Boron pairs well with Vitamin D.

Stacking note
Works well together

Boron pairs well with Magnesium.

Stacking note
Works well together

Boron pairs well with Calcium.

Stacking note
Works well together

Calcium pairs well with Magnesium.

Stacking note
Works well together

Copper pairs well with Zinc.

Stacking note
Works well together

Copper pairs well with Iron.

Stacking note
Works well together

Iodine pairs well with Selenium.

Stacking note
Works well together

Iron pairs well with Vitamin C.

Stacking note
Works well together

Magnesium pairs well with Vitamin B6.

Stacking note
Works well together

Magnesium pairs well with Zinc.

Stacking note
Works well together

Vitamin A pairs well with Zinc.

Stacking note
Works well together

Vitamin A pairs well with Vitamin D.

Stacking note
Works well together

Vitamin A pairs well with Vitamin E.

Stacking note
Works well together

Vitamin B1 (Thiamine) pairs well with Magnesium.

Stacking note
Works well together

Vitamin B12 (Cobalamin) pairs well with Folate.

Stacking note
Works well together

Vitamin B12 (Cobalamin) pairs well with Iron.

Stacking note
Works well together

Vitamin B2 (Riboflavin) pairs well with Magnesium.

Stacking note
Works well together

Vitamin B6 pairs well with Zinc.

Stacking note
Works well together

Folate pairs well with Vitamin B6.

Stacking note
Works well together

Vitamin C pairs well with Vitamin E.

Stacking note
Works well together

Vitamin E pairs well with Selenium.

Stacking note
Works well together

Selenium pairs well with Zinc.

Stacking note
Works well together

Zinc pairs well with Vitamin C.

Stacking note
Not medical advice. This tool surfaces well-established and known interactions from our reference data and curated rules. It is not exhaustive, can’t see your full health picture, and an absence of findings does not mean a combination is safe. Always consult a doctor or pharmacist about your supplements and medications.