Table 1.

Vitamin C concentration-function relationship: Pathology - vitamin C deficiency or low level in diseases; Physiology - normal range of plasma vitamin C level: enzymatic cofactor and antioxidant; Pharmacology - high dose intravenous vitamin C administration: pro-oxidant effects.

Plasma vitamin C concentration	Vitamin C intake	Physical condition	Function (biochemical or clinical outcomes)
<11.4 μmol/L	~ <10 mg daily, P.O.	Pathological	Vitamin C deficiency, hypovitaminosis C, and diseases: scurvy, cancer, sepsis, gastric ulcer, and more diseases
27 ~ 100 μmol/L	<200 mg daily, P.O.	Physiological	Collagen, carnitine, and neurotransmitters synthesis; enzymatic cofactor- electron donor; antioxidant; support immune system etc.
mmol/L level	>1 g/injection, IV	Pharmacological	Pro-oxidant effects on disease treatment: cancer, bacterial or virus infections, burn, allergy, and more

PO, per os; IV, intravenous.