Free Tool

Supplement Interaction Checker

Enter two supplement ingredients to instantly check if they have any known interactions, absorption conflicts, or synergistic benefits.

Taking Multiple Supplements?

The interaction checker works for pairs. For a full stack analysis covering all your supplements at once, try NutriAudit.

Full Stack Audit (Free)

How Supplement Interactions Work

Supplement interactions occur when two or more ingredients affect each other's absorption, metabolism, or effectiveness. These can be negative (reducing absorption or causing side effects) or positive (enhancing benefits when taken together).

Types of Interactions

  • Absorption Inhibition — One ingredient blocks or reduces the absorption of another (e.g., Calcium reduces Iron absorption)
  • Competition — Two minerals compete for the same absorption pathway (e.g., Iron and Zinc)
  • Ratio Imbalance — Optimal ratios between nutrients are disrupted (e.g., Calcium:Magnesium should be ~2:1)
  • Side Effects — Combining certain supplements increases risk of adverse effects

Common High-Risk Interactions

  • Iron + Zinc — compete for absorption; take separately
  • Calcium + Iron — calcium blocks iron absorption; space 2+ hours apart
  • Vitamin E + Vitamin K — high-dose Vitamin E may interfere with Vitamin K clotting function
  • St. John's Wort + Antidepressants — risk of serotonin syndrome
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Not medical advice. Always consult a qualified healthcare professional for personal medical decisions.