Is 15mg of intravenous (IV) vitamin C (ascorbic acid) harmful?

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Last updated: December 23, 2025View editorial policy

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15 mg IV Vitamin C is Completely Safe

A dose of 15 mg of intravenous vitamin C will not hurt you and is well below any threshold for harm. This dose is actually within the standard pediatric maintenance range and far below doses associated with any adverse effects.

Why This Dose is Safe

Comparison to Standard Dosing

  • Pediatric guidelines recommend 15-25 mg/kg/day IV for preterm and term infants, meaning a 1 kg infant safely receives this dose daily 1
  • Adult maintenance dosing in parenteral nutrition is 100-200 mg/day, making 15 mg approximately 7-13% of a standard daily dose 1
  • Critical illness protocols use 2,000-3,000 mg/day IV (2-3 grams), which is 133-200 times higher than your proposed dose 2, 3

Safety Profile of Much Higher Doses

  • High-dose IV vitamin C (≥6 grams/day) shows no consistent evidence of harm compared to placebo in double-blind randomized controlled trials 4
  • In a survey of 11,233 patients receiving an average of 28 grams every 4 days (approximately 7,000 mg/day), only 101 patients (1.1%) experienced side effects, mostly minor (lethargy, fatigue) 5
  • Doses up to 50 grams IV have been studied with the main documented serious adverse events occurring only in patients with known contraindications 4, 6

Known Contraindications (Not Relevant at 15 mg)

The following contraindications apply to high-dose vitamin C (grams, not milligrams):

  • G6PD deficiency: Risk of hemolysis, but only reported with gram doses 4, 5
  • Severe renal impairment: Risk of oxalate nephropathy, but 5 cases total were reported across all high-dose studies 4
  • Hemochromatosis: Theoretical concern about iron absorption 2

At 15 mg, none of these contraindications are clinically relevant.

Practical Context

  • Your dose is 400 times smaller than doses that have caused documented oxalate nephropathy 4
  • Your dose is 187 times smaller than the average dose used by CAM practitioners without significant adverse events 5
  • Even patients with renal impairment are safely given 100 mg/day, which is still 6.7 times higher than your dose 7

In summary: 15 mg IV vitamin C poses essentially zero risk of harm and is a fraction of standard therapeutic doses used safely in clinical practice.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Vitamin C in Sepsis: Evidence-Based Recommendations

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guidelines for Administering Intravenous (IV) Vitamin C

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Vitamin C Dosing in Renal Impairment

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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