Recent research from the Treebak Group at the University of Copenhagen has challenged the idea that low levels of NAD⁺, a molecule essential for energy production in cells, drive aging and frailty. A study published in Cell Metabolism found that reducing skeletal muscle NAD+ levels in mice by 85% did not accelerate aging or impair whole-body metabolism.
In contrast to speculation, the researchers discovered that healthy skeletal muscle function is not as reliant on high levels of NAD as previously thought. When mice had lower-than-normal NAD levels in their muscles, they showed no significant decline in muscle size, overall health, strength, and exercise performance. In fact, detailed studies revealed normal cell gene expression, proteins, mitochondria, and DNA markers despite the low NAD levels.
However, these mice did exhibit increased energetic stress during exercise and minor changes in energy processing, but their overall markers of whole-body and muscle health remained unchanged. This suggests that reducing muscle NAD levels beyond what occurs with normal aging does not lead to muscle weakness or accelerated aging.
The findings are a surprise, as many people have reported benefits from supplementing with NAD precursors, including tech millionaire Bryan Johnson, who takes over 50 pills a day. The research challenges the prevailing view that NAD+ decline is a primary driver of muscle aging and frailty, providing new insights into the relationship between NAD levels and healthy aging.
Source: https://medicalxpress.com/news/2025-05-trash-supplements-nad-aging.html