What the Research Shows About NAD+ Supplements
A friend of mine mentioned she's been hearing a lot about NAD+ supplements lately, so I decided to dig into what the research says. NAD+ supplements, mainly nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), are sold on claims about slowing aging, boosting energy, and improving physical performance. A bottle can run $40 or more a month, so it's worth knowing what you're paying for before you buy in.
Pathway
NR and NMN are two different supplements sold to do the same thing: raise NAD+, a molecule your cells use for energy production and for repair processes believed to decline with age. That belief is the premise behind NAD+ anti-aging marketing: more NAD+ is supposed to support processes your body does less of as you get older.
Not everyone agrees that NAD+ levels decline with age. A 2026 study measured whole-blood NAD+ across seven separate groups, including older adults and frail patients, and found that levels stayed flat with age, and didn't move with diet or exercise either. An earlier study on skin tissue found the opposite: NAD+ levels really did decline with age. Together, the two studies suggest NAD+ decline isn’t consistent across the body, and could depend on the specific tissue being measured rather than being a universal effect of aging.
Research
A 2025 trial gave healthy adults 1 gram of NR or NMN daily and found blood NAD+ roughly doubled within two weeks.
A 2025 review pooled 10 randomized trials of NMN, 437 people total, and checked whether it made people physically stronger, tracking things like grip strength and muscle mass. The improvement was so small it could have happened by chance, rather than the supplement having an effect. A few smaller trials found narrower benefits, like healthier blood vessels or better blood sugar control in prediabetic women, but nothing to back up a broad anti-aging claim. Most of the dramatic results about anti-aging come from studies in yeast, worms, or mice, which don’t translate reliably to people.
Doses up to 1200 mg have looked safe over several weeks, but daily use over months or years has not been tested. There’s also a flagged concern that high doses could affect the liver.
Marketing
You've probably seen NAD+ boosters marketed around aging, energy, and performance, often citing sirtuins or "cellular aging clocks."
Here's the catch: NR and NMN do raise NAD+ levels in the blood, but raising NAD+ and slowing aging aren't the same thing. The systematic review above found grip strength and muscle mass barely moved in humans, and the improvement could have happened by chance. The strong anti-aging results are still mostly found in rodents.
So "raises NAD+" is technically true. It's just being sold like that guarantees slower aging or better performance, when the human research hasn't shown that yet.
General Conclusions
NAD+ supplements reliably raise NAD+ in the blood, but that hasn't been shown to translate into slower aging, more energy, or better workouts in humans yet.
NAD+ might not even reliably decline with age, which means the basic logic behind these supplements may not hold up.
The doses studied so far look safe over a few weeks, but long-term safety hasn't been tested.
If NAD+ supplements are on your radar, I'd love to know why. Drop it in the comments, I'm always curious to see how it lines up with current research.
References
Yang, et al. (2025). An Updated Review on the Mechanisms, Pre-Clinical and Clinical Comparisons of Nicotinamide Mononucleotide (NMN) and Nicotinamide Riboside (NR). Food Frontiers.
https://iadns.onlinelibrary.wiley.com/doi/10.1002/fft2.511
The differential impact of three different NAD+ boosters on circulatory NAD and microbial metabolism in humans. (2025). Nature Metabolism.
https://www.nature.com/articles/s42255-025-01421-8
The Effect of Nicotinamide Mononucleotide and Riboside on Skeletal Muscle Mass and Function: A Systematic Review and Meta-Analysis. (2025).
https://pubmed.ncbi.nlm.nih.gov/40275690/
Human whole-blood NAD+ levels do not vary with age or lifestyle interventions. (2026). Nature Metabolism.
https://www.nature.com/articles/s42255-026-01537-5