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

This is a single-site, prospective, randomized, open-label, parallel 4-arm pilot trial designed to evaluate the safety and pharmacodynamic effects of Niagen®Plus (nicotinamide riboside chloride, NRCl) when administered by injection. The study includes two phases over approximately 100 days per participant. In Phase 1, participants receive three consecutive daily injections of Niagen®Plus (50 mg or 100 mg; subcutaneous or intramuscular) administered in clinic on Days 1-3, followed by a Day 10 follow-up visit for safety evaluation and laboratory testing. In Phase 2, participants continue self-administration of subcutaneous Niagen®Plus at home three times per week (Monday, Wednesday, Friday) through Day 100, returning to the clinic on Days 40 and 100 for repeat safety assessments, sample collection, and exploratory analyses. Primary endpoints assess safety and tolerability through vital signs, comprehensive metabolic and hematologic panels (CMP, CBC, homocysteine), and adverse-event monitoring. Secondary endpoints include changes in whole-blood NAD⁺ concentrations measured by dried-blood-spot analysis and clinician- and participant-reported injection experience. Exploratory endpoints include fatigue, energy, sleep, and quality-of-life assessments; plasma biomarkers of inflammation (C-reactive protein); phenotypic age calculation; oxidative stress testing (in urine); mitochondrial efficiency testing; and subjective evaluations of skin appearance. The target enrollment is 40 generally healthy adults (10 per arm). The study is not powered for hypothesis testing but will inform the design of subsequent placebo-controlled trials by characterizing safety profiles, pharmacokinetic trends, and feasibility of at-home administration.