12/18/2025
As a nurse practitioner, this is the biggest difference I see between oral and IV vitamins:
1️⃣ Absorption Rate
• Oral vitamins: ~20–50% absorbed (less if you have GI issues, inflammation, or low stomach acid)
• IV vitamins: ~100% bioavailability
2️⃣ Speed of Effect
• Oral vitamins: Can take weeks to build measurable levels
• IV vitamins: Blood levels increase immediately during infusion
3️⃣ Dose Limitations
• Oral vitamins: Limited by gut tolerance (hello nausea and diarrhea 👋)
• IV vitamins: Can safely deliver much higher therapeutic doses under medical supervision
4️⃣ Consistency & Reliability
• Oral absorption varies person to person (food, meds, gut health)
• IV delivery is consistent and predictable