Summary
NAD+ is not a peptide. It is a coenzyme built from two nucleotides, present in every living cell, where it carries electrons in the reactions that release energy from food. It has a page here because it is the single most widely stocked product across the listings in this directory. Levels fall with age, which is the premise behind selling it.
What it targets
The important distinction in this literature is between NAD+ itself and its precursors. A 2026 systematic review of 113 studies, 33 of them human intervention studies, found that oral precursors nicotinamide riboside and nicotinamide mononucleotide reliably raise NAD-related molecules in blood and cells and are generally well tolerated over weeks to months, while their effects on function, metabolism and other ageing-related outcomes were mixed and often absent. No eligible outcomes trial has evaluated intravenous or intramuscular NAD+ itself for anti-ageing or wellness. Of the individual trials linked here, one in healthy middle-aged and older adults confirmed a precursor raises NAD+ in people and pointed to blood pressure and arterial stiffness as questions for future work; a 40-person trial in COPD found a marker of airway inflammation fell by about half; and a 20-person pilot in mild cognitive impairment was a safety study rather than a test of benefit. All three used precursors taken by mouth.
Clinical Research
Suppliers stocking NAD+
22 of the 30 listed suppliers. Each row opens its full listing.