What age changes in NAD+
Falling NAD+ with age leaves the value of pills unsettled
Opening a jar may take more effort than it once did. NAD+ research asks about changes with age, but hasn't shown that a pill restores your strength.
A pill has not been shown to make people younger
A weaker grip may leave you wondering whether your body lacks something a pill could replace. Research on NAD and aging asks about falling NAD+ and whether replacement changes health.
Older animals often lose NAD+ faster than their bodies replace the supply. Far fewer studies have checked whether the same fall occurs in older people.
Pills containing NR or NMN supply the body with ingredients for producing fresh NAD+. Higher blood levels after these pills don't show that you would lift more or cope better with chores.
Aging mice lost NAD+ faster; cell changes help explain why
Studies in aging mice found a protein becoming more active and using up more NAD+ [2]. Proteins have many jobs, and this protein uses up some of the supply cells need.
Breeding mice without this protein preserved NAD+ and helped energy production into old age [2]. A review explains that less NAD+ leaves less available for proteins doing repair work [5].
That shortage can disturb energy use even when the cells have enough oxygen. The finding concerns cell work; it doesn't show that your blood lacks oxygen as you age.
Another review describes aging cells that stay alive but stop making new cells [14]. These old cells release substances that keep inflammation going, so the response to injury continues.
The released substances prompt immune cells, part of the body's defenses, to produce more protein for breaking down NAD+. More of that protein means more NAD+ is lost, while the old cells keep the response going.
A 2024 review discussed animal treatments that raise NAD+ while also using drugs to clear away these old cells [14]. Those ideas haven't established a way to bring back your strength.
People improved in walking and sugar tests; animal findings went further
Middle-aged adults taking NMN for 60 days walked farther and had higher blood NAD+ [3]. After menopause, women given NMN for 10 weeks showed better muscle responses when given insulin, a hormone involved in blood sugar control [1].
The trials didn't show reversed aging or prove that the improved sugar response meant more strength. A 2025 review found that few studies had confirmed a fall in NAD+ as people aged [13].
The reviewers judged human health gains uncertain despite higher blood levels. Stronger findings in animals leave open what you might notice from treatment.
A 2024 review grouped NMN findings into four areas, mainly from animals or from cells grown for testing in dishes [15]. The areas were energy, cell survival, the immune system's response, and protection of DNA, where cells keep their instructions.
Older animal cells showed more activity from proteins involved in energy and survival after NMN. Other proteins broke down less NAD+, while DNA repair proteins also used less NAD+.
Using less NAD+ during repairs doesn't by itself show that the cells did more repairs. Nor does a changed immune response by itself mean better protection from illness.
Another review found fewer signs of cells that had stopped making new cells in older mice given NMN [14]. Changes in mouse cells can't tell you whether taking NMN would make daily work easier.
Extra NAD+ could help cancer cells as well as healthy cells
Cells kept alive in a dish released more substances that keep inflammation going when their NAD+ production increased [8]. The increased release continued even after those cells stopped making new cells.
The authors cautioned against treating a rise in NAD+ as harmless. Their work didn't establish that a particular pill harms an older person.
A review raises another concern: growing cancer cells need NAD+, so an existing cancer might use extra NAD+ to grow [13]. The answer may differ between cancers, and researchers haven't settled the risk.
Your cancer care team needs to consider a supplement alongside your cancer and treatment. These findings raise a question for that discussion; they don't predict what would happen to you.