Home › Guides › NAD+ Guide: What It Is and How Supplements Raise It
Trusted Health Reviews editors · October 2026
NAD+ Guide: What It Is and How Supplements Raise It
We explain NAD+ and why levels may fall with age. We also cover what small human trials of NMN and NR show about raising it, the safety picture and what remains unproven.
In briefChecked October 2026
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme that all cells depend on, both for turning food into energy and for enzymes that repair DNA and relay cell signals. In animals, and in some human tissues, it seems to become scarcer with age. Two forms of vitamin B3, NMN and NR, do reliably push blood NAD+ up in small, short human trials. Past that point the benefits are limited and mixed, and nothing shows either one slows aging.
Defining NAD+ Simply
Each living cell contains this coenzyme. In the reactions that convert food to usable energy (ATP), it moves electrons around. Other enzymes consume it as well: PARPs, which help repair DNA, and sirtuins, which help regulate metabolism and stress responses.
Reasons NAD+ May Fall With Age
Some animal work and human tissue work suggests NAD+ levels decline over the years. Two explanations have been put forward. One is lower activity of NAMPT, a key enzyme that recycles NAD+. The other is heavier use of NAD+ by enzymes such as CD38 and PARPs. In people, the size of the decline and its importance for health are still being worked out.
Supplements That Lift NAD+
NMN (nicotinamide mononucleotide): small placebo-controlled trials of 2 to 12 weeks (about 10 to 110 people each, 250 to 1,250 mg a day) show it reliably raises blood NAD+. Modest shifts in muscle insulin sensitivity, walking distance or grip strength were reported by a few. Overall the results are mixed, and NMN makers funded several of the trials. The FDA said in September 2025 that NMN can be sold as a dietary supplement.
NR (nicotinamide riboside): human research on NR is more extensive. In a 2023 review of 25 human studies, blood NAD+ rose reliably but there was no sign of a rise in muscle, and few clinically meaningful benefits turned up.
Resveratrol: it is not a precursor of NAD+. People promoted it as a sirtuin activator, but scientists debate whether it directly activates SIRT1 in the body, and human trials report small, inconsistent effects.
Exercise: a sensible habit for many reasons. Researchers are still studying how it affects NAD+ in people.
As for which is better, no published trial in people has shown NMN beating NR, or NR beating NMN, at raising NAD+. None has shown that either one slows aging.
NMN was well tolerated in published trials at 250 to 2,000 mg a day, and NR at up to 1,000 mg a day. Because those studies were small and short, long-term safety is unknown. Pregnant? Being treated for cancer? On diabetes or blood pressure medicines? Talk to your doctor first. GenuinePurity Liposomal NMN is our top pick among NMN supplements and gives 500 mg of NMN in each 2-capsule serving; the product itself has not been tested in a trial.
A coenzyme that every cell contains, NAD+ (nicotinamide adenine dinucleotide) supports energy metabolism. DNA repair enzymes (PARPs) and metabolic regulators (sirtuins) draw on it as well.
Studies in animals and in some human tissues hint at a decline, perhaps because the enzyme NAMPT recycles less NAD+ while enzymes such as CD38 and PARPs use more. Scientists haven't pinned down how far it drops in people.
Both NMN and NR reliably raise blood NAD+ in small human trials, and NR has the larger body of published research. Apart from raising NAD+ levels, neither has been shown to improve health or slow aging in people.
Not in any published human trial. Because they're different molecules, matching up milligrams isn't very informative.
Diet and exercise support overall metabolic health, and studies of how they affect NAD+ in people are continuing. Supplements do raise blood NAD+, but whether that improves health is not yet known.
Disclaimer: This page is for information only. These are dietary supplements, not medicines. Not intended to diagnose, treat, cure or prevent any disease. Not evaluated by the FDA. Results differ between people. Check with a healthcare professional. We earn a commission when you buy through our links. We only cover brands we have affiliate relationships with, so our top picks are the best of the products we cover, not the best of every product on the market. Read the full disclaimer
Can we use Google Analytics cookies? They help us count visits and see which pages people find useful. They log the pages you open, and some of those cover health topics. Nothing is switched on unless you accept. Privacy Policy
Ad
GenuinePurity NMN
Ad · affiliate link; we earn a commissionSee pricing