NAD+ Decline and Muscle Health: New Study Insights

In recent discussions regarding the implications of supplement consumption in relation to aging, a new study brings into question the significance of NAD⁺ levels. This topic has garnered attention particularly because of the popular media narrative surrounding health and longevity supplements.

The Significance of NAD⁺

NAD⁺, or nicotinamide adenine dinucleotide, plays a crucial role in cellular metabolism. It is integral for energy production and various other essential cellular processes. As humans age, NAD⁺ levels can decline significantly—by as much as 30%. This decline has led to the widespread belief that supplementing with NAD precursors could potentially counteract aspects of aging.

New Findings from the University of Copenhagen

A study published in the esteemed journal Cell Metabolism by researchers from the NNF Center for Basic Metabolic Research at the University of Copenhagen challenges this long-held assumption. The research team, led by Associate Professor Jonas Treebak, investigated whether substantial reductions in skeletal muscle NAD⁺ levels could impair muscle function or accelerate aging.

Methodology

The study utilized a genetically engineered mouse model in which scientists could specifically reduce NAD⁺ levels in the skeletal muscle of adult mice. This allowed the researchers to evaluate the impacts of decreased NAD⁺ without the confounding factors associated with muscle development.

Key Findings

The findings were surprising:

• Reduction of NAD⁺ Levels: Researchers achieved an 85% reduction in skeletal muscle NAD⁺ levels.
• No Impairment of Muscle Function: Contrary to expectations, these mice maintained normal muscle size, strength, and exercise performance.
• Mitochondrial and Genetic Health: Markers related to cellular health, including gene expression and mitochondrial function, did not show deterioration.

As noted by Sabina Chubanava, a Ph.D. student involved in the research, “Healthy skeletal muscle function is not as reliant on high levels of NAD⁺ as previously thought.”

Implications for Supplementation

This research raises critical questions regarding the efficacy of NAD⁺ supplements which have become popularized by personalities like Bryan Johnson, who reportedly consumes more than 50 pills a day including NAD precursors. If skeletal muscle can function adequately with reduced NAD⁺ levels, the reliance on supplementation may be unwarranted.

Researchers caution against hastily adopting these supplements as a panacea for aging. As the study concludes, the relationship between NAD⁺ levels and aging, particularly in muscle health, is far more complex than previously believed.

“Our results suggest that skeletal muscle can tolerate substantial NAD depletion without loss of function or accelerated aging.” – Dr. Jonas Treebak

Future Directions

Further investigations are needed to fully unravel the implications of these findings. Possible future research may include:

• Exploring NAD⁺ levels during different life stages
• Investigating mechanisms of energy metabolism independent of NAD⁺
• Understanding the impact of dietary and lifestyle factors on NAD⁺ levels

Understanding the true influence of NAD⁺ on health and aging could reshape not only dietary supplementation approaches but also broader public health recommendations.

Conclusion

The current body of evidence suggests that while NAD⁺ is undoubtedly important for cellular function, its decline may not be the primary driver of age-related muscle frailty. The implications of this study may lead to a reevaluation of the necessity of NAD⁺ supplementation in the quest for longevity and health.

Further Reading

For more information, read the original study: NAD depletion in skeletal muscle does not compromise muscle function or accelerate aging, _Cell Metabolism_ (2025).

References

• Chubanava, S. et al. (2025). "NAD depletion in skeletal muscle does not compromise muscle function or accelerate aging." Cell Metabolism. DOI: 10.1016/j.cmet.2025.04.002.
• Treebak, J. et al. (2025). University of Copenhagen Study.
• Johnson, B. Don’t Die: The Man Who Wants to Live Forever (Netflix Documentary).