This is a randomized, 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. Approximately 36 participants will be randomized 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, assessed via in lab blood collection at baseline and study completion. Secondary endpoints include questionnaires measuring health-related cognitive functioning and stress (PROMIS Cognitive Function - Short Form 8a and the Perceived Stress Scale-10), the Single-item Assessment of Immune Fitness, evaluation of safety and tolerability, and an Overall Experience Questionnaire (Appendices 1, 4-7). All assessments, including electronic questionnaires, are completed remotely without in-person visits.

Inclusion criteria:

Provide voluntary, written, informed consent to participate in the study. Agree to provide a valid cell phone number and are willing to receive communications through text.

Can read and write English. Willing to complete questionnaires, records, and diaries associated with the study.

Healthy male and female participants aged 25 years or older. Willing to go to an Ulta Labs Patient Service Center location for a Blood Vitamin C Test (baseline and Day 29) and located within a convenient distance of participating locations. [Note: The services offered by Ulta Lab Tests are available only in the United States and not to residents of the states of New Jersey, New York, and Rhode Island.] Willing to avoid starting new or stopping any existing dietary supplements throughout the study.

Exclusion criteria:

Women who are pregnant, breastfeeding, or planning to become pregnant or start breastfeeding during the trial.

Known food intolerances/allergy to any ingredients in the product. Having any of the following conditions: Psychiatric conditions, neurologic disorders, endocrine disorders, cancer.

Having had a significant cardiovascular event in the past 6 months. Taking MAO inhibitors, SSRIs, or any other psychiatric or neurological medicines On immunosuppressive therapy. Adults lacking capacity to consent.

28 days