Emergen-C study: can a daily vitamin boost your energy?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Participant's provision of a signed and dated electronic informed consent document indicating that the participant has been informed of all pertinent aspects of the study before any assessment is performed. * Healthy adults, 18-64 years of age at the time of electronic consent (does not exclude any ethnicities, races, or gender identities). * Participant is seeking to improve their energy/less fatigue levels. * Participants whose baseline score is greater than or equal to (\>=) 10 on the dimension of general fatigue of the MFI and a score \>=3 for at least ten of the 20 questions of the MFI. * Participants who are willing and able to comply with all study related activities as shown in the Schedule of Activities. * Participants who reside in the United States (except for Hawaii and Alaska). * Participants who own a mobile device, tablet or computer with access to stable internet connection and are willing to use their device to complete study surveys and assessments. Exclusion Criteria: * Participants who are either directly involved in the conduct of the study or a member of their immediate family; or a Haleon employee directly involved in the conduct of the study or a member of their immediate family. * Participants who have participated in other studies (including non-medicinal studies) involving investigational product(s) within 30 days prior to study entry and/or during study participation. * Participants who are pregnant, lactating, or plan to be pregnant or lactating during the course of the study (self-report). * Participants with known or suspected intolerance or hypersensitivity to any study materials (or closely related compounds) or any of their stated ingredients. * Participants who are hypertensive or salt-sensitive should be excluded from this study. * Participants who report being a heavy drinker (defined as drinking 3 or more alcoholic beverages per day). * Participants who are unable to read and understand English. * Participants who report current and/or recent (up to 3 months ago) major illnesses and/ or major surgery. * Participants who report a planned surgery during the study duration. * Participants who report a diagnosis of heart failure, heart rhythm disturbances, severe liver disease, severe mental health diagnosis, or severe renal failure. * Participants who report taking medications (in the previous 21 days) that have well established moderate or severe interaction with any of the study product ingredients: Anticoagulants, antihypertensives, anxiolytics, antidepressants, chemotherapy, immunotherapy, sedative hypnotics, medications that warn against grapefruit consumption, corticosteroids at doses greater than 5 milligrams (mg) per day, diabetic medications, oral anti-infectives (antibiotics, antifungals, antivirals) to treat an acute infection, antipsychotics, Monoamine Oxidase Inhibitors (MAOIs), or thyroid products. * Participants who are currently taking a multivitamin or have taken a multivitamin in the past 30 days and are not willing to stop taking a multivitamin for the duration of the trial. * Participants who are currently taking other Vitamin C or B supplements or have taken Vitamin C or B supplements in the past 30 days and are not willing to stop taking other Vitamin C or B supplements for the duration of the trial. * Participants who are currently consuming energy drinks or energy shots or have consumed an energy drink or energy shot in the past 30 days and are not willing to stop consuming energy drinks and energy shots for the duration of the trial. * A participant who has previously been enrolled in this study. * A participant who, in the opinion of the investigator or delegate, should not participate in the study.