High-dose vitamin C for cancer is usually an intravenous add-on, not a cure or ordinary supplement. Only infusion reaches blood levels that stress many cancer cells. After enzyme and kidney screening, short-term safety is generally favorable. Quality-of-life and milder chemotherapy side-effect gains are more consistent; survival signals are disease-specific and unconfirmed. Oral megadoses do not match intravenous levels. (Full Review)
| Marker | Target | Why |
|---|---|---|
| G6PD enzyme activity | Within lab normal (deficient = avoid high-dose IV) | Prevent hemolysis |
| Creatinine / eGFR | Stable near personal baseline | Oxalate/renal risk |
| Serum electrolytes (Na, K) | Within lab normal | Osmotic/sodium load from formulations |
| Complete blood count | Stable; watch Hb/Hct drop | Detect hemolysis or chemotherapy toxicity |
| Plasma ascorbate (optional) | ≥50 µmol/L for deficiency correction | Confirm repletion |
| Tumor markers / imaging | Per oncology plan | Disease control |
| Point-of-care glucose | Use lab plasma if decision-critical around infusion | Meter interference |
Cadence: Baseline; after first 1–2 high-dose infusions; every 2–4 weeks during intensive twice- or thrice-weekly IV; with each chemotherapy cycle when combined. Imaging/tumor markers per oncology schedule (often every 2–3 months).