Aging  and muscle function is unrelated to NAD depletion

Energy metabolism and key enzymatic reactions of proteins require nicotinamide adenine dinucleotide (NAD) and dysregulations of NAD metabolism are widely regarded as detrimental to health, with NAD depletion commonly implicated in aging. But, the extent to which cellular NAD concentration can decline without adverse consequences remains unclear.

To answer the question, the researchers generated a mouse model in which nicotinamide phosphoribosyl transferase (NAMPT)-mediated NAD⁺ biosynthesis was selectively disrupted in adult skeletal muscle.

The authors show that NAD depletion in skeletal muscle does not impair tissue integrity and function or accelerate aging, as shown in a mouse model with an 85% decrease in muscle NAD+ levels.

Muscle structure, metabolism, and mitochondrial function remain unaffected, suggesting that NAD depletion does not drive age-related muscle decline.

https://www.cell.com/cell-metabolism/fulltext/S1550-4131(25)00212-8

https://sciencemission.com/NAD-and-muscle-function-and-aging