What have studies proved about NAD+?
Pills can raise a blood level. Better health and longer life remain unproved.
What can NAD+ pills actually do?
Two pill forms, called NMN and NR, can raise blood NAD+. NAD+ is a helper found in every cell. It lets cells release the energy held in food. Cells also spend NAD+ when they mend damaged DNA. Body tissue often holds less NAD+ with age. Swallowed NAD+ does not pass through the gut well. Most pills therefore contain a smaller starting piece instead. The letters NMN and NR are short labels for those pieces. Your body can turn either piece into NAD+. Studies haven’t shown longer life or better health from these pills. A changed blood test may not change how you feel.
Which jobs does NAD+ do inside you?
Every living cell contains the helper called NAD+ [5]. A cell relies on it to release energy stored in food [5]. Cells also spend NAD+ when they mend DNA. Three groups of helper proteins share much of this work. One group guides daily cell care; another group mends damaged DNA. A third group breaks old NAD+ apart [5][6][13]. These jobs continue throughout your life, though the supply can change. The body makes NAD+ on its own. The FDA has not approved NAD+ as a drug.
What changed in NAD+ pill studies?
Stores sell NAD+, NMN, and NR as supplements. The FDA has not approved any of them to prevent or treat disease [5]. One study followed adults in good health who carried extra weight. Their blood NAD+ rose 22%, 51%, and 142% with NR. The study amounts were 100, 300, and 1000 mg/day for 8 weeks [4]. Another group received NMN at 300-900 mg/day for 60 days. NAD+ in their blood rose at every amount. The adults also walked farther [3].
Those blood changes don’t prove that health improved. A 2025 review found little proof of longer life or better health [14]. The blood number rose, but lasting health gains did not follow. Read the NAD+ study findings as research, not product advice.
Why is swallowed NAD+ different from NMN or NR?
Most swallowed NAD+ never crosses the gut wall [8][9]. The smaller starting pieces are called NMN and NR. Both cross more easily, and your body can rebuild NAD+ from either piece. NMN needs one change inside the body. NR needs two changes [8]. Niacin is another starting piece [5].
Cells also reuse parts left from old NAD+. They can begin with niacin, NR, or a part of food protein called tryptophan [5][8]. Knowing the route names won’t settle your choice. An NMN or NR study did not test swallowed NAD+. The NMN and NR comparison keeps the forms apart.
Why does the body hold less NAD+ with age?
NAD+ usually grows scarcer as people age [5][10]. Older skin held less NAD+ in one human study. The same skin showed more DNA repair work [7]. That repair work uses up NAD+. When mice lacked one protein, their tissue kept more NAD+ [2]. One review put the loss near 10-50% across adult life [10]. Few human studies were available, so the exact loss remains unsure.
That loss helps explain the interest in NMN and NR. It doesn’t show that either pill slows aging. The NAD+ and aging page marks where the proof ends for your health.