Liposomal Vitamin C: Better Absorption? Study Says Yes

Key Findings

This study demonstrated that a single oral dose of liposomal vitamin C exhibited 1.77 times higher bioavailability compared to an equivalent dose of non-liposomal vitamin C in healthy adults under fasting conditions. Bioavailability was assessed via plasma concentration-time curves (AUC). The liposomal formulation showed significantly higher systemic exposure, though peak plasma concentrations (Cmax) did not differ significantly between formulations. The liposomes were confirmed to have a core-type structure, sub-100 nm particle size (99.8 ± 0.4 nm), and 65.85% ± 1.84% encapsulation efficiency.

Study Design

This was an open-label, randomized, single-dose, two-treatment, two-sequence, two-period, crossover study conducted in 12 healthy adult subjects. Participants received either liposomal or non-liposomal vitamin C first, followed by the alternate formulation after a washout period. All subjects were studied under fasting conditions. Bioavailability was evaluated by measuring plasma vitamin C levels over time. The liposomal product was characterized using TEM, DLS, and zeta potential measurements prior to clinical testing.

Dosage & Administration

The study compared equimolar oral doses of vitamin C delivered via liposomal and non-liposomal (standard aqueous solution) formulations. Exact milligram doses were not specified in the provided summary, but doses were matched for vitamin C content. Administration occurred orally under strict fasting conditions (overnight fast), with blood sampling conducted over the subsequent period to measure pharmacokinetics.

Results & Efficacy

The primary efficacy outcome was relative bioavailability, measured by the ratio of AUC(0-t) (area under the plasma concentration-time curve from zero to last measurable concentration). Liposomal vitamin C showed a 1.77-fold higher AUC(0-t) compared to non-liposomal vitamin C. This difference was statistically significant (p < 0.05). Particle characterization confirmed the liposomal formulation had a mean size of 99.8 ± 0.4 nm and 65.85% ± 1.84% encapsulation efficiency. No significant difference was observed in Cmax between the two formulations.

Limitations

Key limitations include the small sample size (n=12), which reduces statistical power and generalizability. The study only included healthy adults under fasting conditions, limiting applicability to diseased populations or real-world fed states. It assessed single-dose pharmacokinetics only, not reflecting chronic supplementation effects or clinical outcomes. The crossover design, while efficient, carries risk of carryover effects despite the washout period. Lack of detailed demographic data (e.g., age range, sex distribution) beyond "healthy adults" is noted.

Clinical Relevance

For supplement users, this study provides evidence that liposomal vitamin C may enhance systemic absorption by 77% compared to standard oral forms when taken fasting. This suggests potential for achieving higher plasma concentrations with equivalent doses, which could be relevant for applications requiring elevated vitamin C levels. However, the study does not demonstrate superior clinical efficacy (e.g., reduced illness duration or improved immune function) – it only confirms a pharmacokinetic advantage. Users should weigh the typically higher cost of liposomal products against this absorption benefit, recognizing that real-world effectiveness in non-fasting states or for specific health outcomes remains unproven by this single-dose trial.