Randomized, Open-label, Safety Study of Subcutaneous and Intramuscular Injections of Niagen® Plus

Inclusion Criteria: * Generally healthy adults, aged 18+ * Demonstrated baseline fatigue as determined by a below average score from the FAS (threshold prespecified in SAP). * NAD+ or NAD+ precursor injection naïve (including intravenous, intramuscular, subcutaneous, or other injection route) (i.e., 8 weeks abstinent) * Non-anemic * Willingness to adhere to lifestyle considerations and study procedures. * Ability to read English, and provide written informed consent. * Willingness to self-administer the study material, via subcutaneous injection for 90 days (days 10-100 of the study), and complete finger prick blood collections. Exclusion Criteria: * One or more uncontrolled chronic illness including but not limited to diabetes, cardiovascular disease, liver, disease, kidney disease, or any form of cancer. An uncontrolled chronic illness, in this case, is defined as any changes to medication or other treatment modalities in the last 90 Days. * More than one chronic disease diagnosis under active treatment. * Any chronic disease, as determined by the primary investigator, that increases risk or confounds safety. * Any acute illness within 14 Days prior to Visit 1 (Day 1). * Cancer diagnosis within the last 5 years * Anemia (as defined by hemoglobin levels below 100 g/L, and other blood measures) * Current pregnancy or lactation; unwilling to use effective contraception if of childbearing potential. * Use of any NAD+ supplement, NAD+ precursor, or vitamin B3 product, orally, nasally, by patch, or injection within the last 60 Days. NAD+ precursors and related compounds include niacin (NA), nicotinamide (NAM), nicotinamide riboside (NR), nicotinamide mononucleotide (NMN), NAD+, NADH, NAD+3, inositol hexanicotinate, apigenin; etc. The exception is the use of a daily oral multivitamin, that may contain vitamin B3 (niacin/nicotinamide). Such use will need to be documented. * Hypersensitivity or allergy to NR, niacin, other forms of vitamin B3/NAD+ precursors, bacteriostatic water * Significant aversion to needles or finger pricks. * Participation in another clinical intervention study, 90 Days (or 5 half-lives of the intervention, whichever is longer) prior to Visit 1 (Day 1). * Any other condition rendering the participant unsuitable per investigator. * Excessive daily use of alcohol, defined as 4 or more drinks on one occasion, or illicit drug use which would prevent adherence to the protocol as determined by the investigator.