What Is NAD+ and Why Does It Matter?
NAD+ is one of the most important molecules in your body. It participates in over 500 enzymatic reactions, including energy production in mitochondria, DNA repair via PARP enzymes, and gene regulation via sirtuins. Without NAD+, you would die in about 30 seconds.
The discovery that NAD+ declines with age — and that this decline contributes to virtually every hallmark of aging — was one of the most significant findings in geroscience. Studies in mice showed that boosting NAD+ could restore muscle function, improve cognitive performance, enhance blood vessel growth, and even reverse aspects of aging in the brain and heart.
NMN vs. NR: The Precursor Wars
Two main NAD+ precursors compete for attention: NMN (nicotinamide mononucleotide), championed by Sinclair, and NR (nicotinamide riboside), backed by ChromaDex and researcher Charles Brenner. Both are converted to NAD+ in the body, but through different pathways.
NR proponents argue it has more human clinical trial data and better bioavailability. NMN proponents point to more dramatic results in animal models and Sinclair's personal endorsement. The scientific community remains divided, and head-to-head human trials are still limited.
What's clear: both raise NAD+ levels. What's unclear: whether that translates to meaningful lifespan extension in humans. The mouse data is compelling. The human data is promising but preliminary.
The $3 Billion Supplement Market
The NAD+ supplement market exploded from virtually nothing in 2017 to over $3 billion by 2025. NMN and NR supplements are sold by hundreds of brands, from pharmaceutical-grade products to questionable Amazon listings.
Quality varies enormously. Third-party testing has found that many NMN supplements contain less than half the labeled dose, while some contain contaminants. Reputable brands like ProHealth Longevity, Alive By Science, and DoNotAge submit to independent testing and publish Certificates of Analysis.
The FDA's 2022 decision to investigate whether NMN should be classified as a drug rather than a supplement sent shockwaves through the industry. The matter remains legally contested, with supplement companies arguing that NMN was sold as a supplement before any drug investigation began.
The Human Evidence So Far
Several human clinical trials of NMN and NR have been completed:
- A 2021 study in Science showed NMN improved muscle insulin sensitivity in prediabetic women.
- A 2022 study showed NMN improved aerobic capacity in middle-aged runners.
- Multiple NR trials have shown increased NAD+ levels in blood with good safety profiles.
- A 2024 trial showed NMN improved sleep quality and reduced biological age markers in older adults.
However, no human study has yet demonstrated that NAD+ boosting extends lifespan. This isn't surprising — such a study would take decades. Most researchers in the field take NAD+ precursors themselves, viewing the risk-benefit ratio as favorable based on animal data, but acknowledge that definitive proof in humans is years away.
