Optimizing Oral Vitamin C Supplementation: Addressing Pharmacokinetic Challenges with Nutraceutical Formulation...

Vitamin C, a water-soluble micronutrient, is one of the most widely used dietary supplements pertaining to its vital role in maintaining overall human health, particularly through its potent antioxidant and immune-supportive functions. This mini review summarizes key pharmacokinetic constraints of vitamin C and evaluates formulation strategies aimed at improving its systemic availability. Achieving sustained optimal plasma levels of vitamin C remains challenging due to its dose-dependent absorption, tissue saturation, rapid renal clearance, and short half-life. These pharmacokinetic limitations restrict systemic retention, with high oral doses providing only marginal increases in plasma concentrations and necessitating multiple daily administrations. Conventional vitamin C supplements show efficient absorption only at low to moderate doses, while higher intakes are restricted by transporter saturation and increased renal excretion. Alternative delivery systems such as liposomal encapsulation, esterified derivatives, nano-emulsions, and co-formulations with bioenhancers have been examined; however, evidence for prolonged systemic retention remains inconsistent. The sustained-release formulation of vitamin C shows more reliable outcomes, demonstrating prolonged plasma exposure, higher steady-state concentrations, and potential for improved compliance through reduced dosing frequency. While further robust comparative studies are needed, current evidence suggest that advanced formulation approaches, particularly sustained-release delivery, may help overcome these pharmacokinetic limitations, thereby supporting improved clinical utility of vitamin C supplementation.