What are NAD+ supplements?
NAD+ supplements are available in a variety of forms — from pills and gels to intravenous infusions at wellness spas.
But here’s the catch: These supplements typically don’t contain NAD+, and that’s because the body has a difficult time absorbing it. NAD+ is a large molecule that doesn’t easily cross cell membranes to enter the bloodstream, Martens explains.
Instead, the supplements usually contain building blocks — also known as precursors — that your body converts to NAD+. Yabluchanskiy says the most common ones are nicotinamide riboside (NR), a form of vitamin B3, and nicotinamide mononucleotide (NMN), which is synthesized from B3. These substances can penetrate cells and change into NAD+.
Niacin, another form of B3, is often not included in NAD+ supplements because high doses can cause side effects like skin flushing or an upset stomach, says Jean Moon, a professor at the University of Minnesota College of Pharmacy.
Do NAD+ supplements offer any benefits?
There is evidence that consuming these NAD+ precursors will increase the amount of NAD+ in the blood, Martens says. “What we know less about is whether the boost in NAD that’s occurring in blood is actually getting to the tissues,” where it could make a difference in how your body works, he explains.
At this point, there’s “no human evidence that NAD can extend lifespan in humans,” Yabluchanskiy adds. Most studies on NAD+ supplementation have been short term and have involved animal subjects. Human studies often show mixed results, but research is ongoing.
NAD+ supplements may have greater potential to address specific health conditions than to address aging overall, Yabluchanskiy says. For instance, some human studies have found that NAD+ supplements may benefit those with peripheral arterial disease (PAD), a condition where the vessels that carry blood from the heart to the legs are narrowed or blocked.
One study published in Nature Communications in 2024, coauthored by Martens, found that the NAD+ precursor NR helped increase walking speed for people over 50 who have PAD. Research coauthored by Yabluchanskiy and published in 2025 in The Journal of Pharmacology and Experimental Therapeutics found that NR could improve blood flow to brain regions involved in memory in older adults with PAD, modestly improving cognition.
However, a different study led by Martens and published in Alzheimer’s & Dementia found that while NR raised blood NAD+ levels in people over 65 with mild cognitive impairment, it didn’t improve cognitive function, blood pressure or cerebral blood flow.
Some research has shown NAD+ supplements could benefit people with Parkinson’s disease. But a recent randomized clinical trial published in JAMA found that NAD+ precursors didn’t improve clinical outcomes for people with Parkinson’s who were 65 and older.
Separately, a 2021 study published in Science found that the NAD+ precursor NMN may improve insulin sensitivity in women in their 60s who are overweight or have obesity and have prediabetes.