Medically reviewed by Dr. Sarah Mitchell, MD

Supplement Interactions & Safety

Supplements can interact with medications, medical conditions, and each other. Here's what you need to know before starting any supplement.

Magnesium Safety & Interactions

Zinc Safety & Interactions

Iron Safety & Interactions

Calcium Safety & Interactions

Vitamin D Safety & Interactions

Omega-3 Safety & Interactions

General Supplement Safety Rules

Latest Safety Articles

Supplements to Avoid: 10 That Don't Work or Are Dangerous

Evidence-based review of supplements that are ineffective, overhyped, or potentially dangerous — including colloidal silver, high-dose vitamin A, and unregulated fat burners.

Can You Take Calcium and Magnesium Together? The Complete Guide

Calcium and magnesium compete for absorption — learn the optimal timing, ratios, and how to take both without reducing effectiveness.

Omega-3 Safety: Bleeding Risk, Contaminants & Drug Interactions

Is omega-3 safe? Learn about bleeding risk, mercury/contaminant concerns, drug interactions, and who should NOT take fish oil supplements.

Vitamin D Safety: Toxicity, Hypercalcemia & Drug Interactions

Is vitamin D safe? Learn about toxicity risk, hypercalcemia, drug interactions, and who should NOT take high-dose vitamin D supplements.

Calcium Safety: Kidney Stones, Heart Risk & Drug Interactions

Is calcium safe? Learn about kidney stone risk, cardiovascular concerns, drug interactions, and who should NOT take calcium supplements.

Zinc Safety: Side Effects, Upper Limits & Drug Interactions

Is zinc safe? Learn about side effects, copper depletion risk, drug interactions, and who should NOT take zinc supplements.

Magnesium Safety: Side Effects, Drug Interactions & Who Should Avoid It

Is magnesium safe? Learn about side effects, drug interactions (blood pressure meds, antibiotics, bisphosphonates), and who should NOT supplement.