Qualia Vitamin C+ for Vitamin C Deficiency

This is a double-blind, placebo-controlled, parallel-group, study evaluating the effect of a Qualia Vitamin C+ formulation on Whole Blood Vitamin C levels in the blood of healthy adults aged 25 years or older that have suboptimal vitamin C blood levels (i.e., 0.4 - 0.9 mg/dL) and those with adequate vitamin C blood levels (≥0.9 mg/dL). Approximately 152 (76 in the suboptimal stratum and 76 in the adequate stratum) participants will be assigned to one of two study arms: Qualia Vitamin C+ or placebo. Each participant will take two capsules of their assigned product once daily in the morning, with or without food, over a 28-day period. The primary outcome is the change in blood vitamin C levels in the suboptimal stratum, assessed via lab blood collection at baseline and study completion. Secondary endpoints include the change in blood vitamin C levels, assessed via lab blood collection at baseline and study completion in the entire group, questionnaires measuring health-related Quality of Life and fatigue (RAND-36 and the FACIT-Fatigue Scale), the Single-item Assessment of Immune Fitness, evaluation of safety and tolerability, and an Overall Experience Questionnaire. Further, a sub-group analysis of fatigued participants meeting at least mild to moderate fatigue as measured by the FACIT-Fatigue will be a secondary objective. The NCI Fruits and Vegetable Screener - All-Day Screener will also be used to assess intake at baseline and study completion. All assessments, including electronic questionnaires, are completed remotely without in-person visits.