Vitamin C Bioequivalence from Gummy and Caplet Sources in Healthy Adults: A Randomized-Controlled Trial

Background: The efficacy of Vitamin C (L-ascorbic acid) supplementation can be assessed by uptake into the blood and retention in leukocytes. Vitafusion® Power C gummy is an alternative vitamin C source which may exhibit similar bioavailability to comparator caplets. Objective: The objective of this study was to evaluate the bioequivalence of vitamin C from a vitafusion® Power C gummy formulation and a comparator caplet in healthy adults. Methods: Thirty healthy men and women, 34.0 ± 11.4 years of age and Body Mass Index (BMI) 24.5 ± 3.6 kg/m² completed the randomized examiner-blind, comparator controlled, cross-over trial with two sequences: gummy (1000 mg) to caplet (1000 mg) or caplet to gummy. Intake of foods fortified with Vitamin C was restricted 7 days prior to each dosing. Blood samples were collected pre-dose and at 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12 and 24 h post-dose for plasma and leukocytes; and urine was collected pre-dose and between 0-2, 2-4, 4-8, 8-12 and 12-24 h post-dose for L-ascorbic acid analysis. Results: Vitafusion® Power C gummy and comparator caplet demonstrated similar plasma absorption profiles as there were no significant differences in plasma L-ascorbic acid total Area Under the Curve (AUC)₀₋₂₄ₕ, and Tₘₐₓ between gummy and caplet. The caplet did elicit a significantly higher Cₘₐₓ than the gummy (p < 0.05), however, the difference was numerically small. Leukocyte L-ascorbic acid total AUC₀₋₂₄ₕ and Cₘₐₓ were not significantly different between gummy and caplet, however Tₘₐₓ of the gummy group was significantly longer (p = 0.012). Urinary L-ascorbic acid levels were also not significantly different between gummy and caplet. There were no serious adverse events and safety parameters remained within normal clinical range for both products. Conclusion: Vitafusion® Power C gummy exhibited similar Vitamin C absorption and bioavailability to a comparator caplet in healthy adults and were considered bioequivalent.