NAD+ boosters may help muscle stem cells fight aging weakness

Muscle weakness is a common part of aging, but scientists are looking for ways to keep our cells working well. A new systematic review looked at nearly 60 studies to see if adding NAD+ precursors like nicotinamide mononucleotide or nicotinamide riboside helps. These substances act as building blocks for NAD+, a molecule that powers our cells. The research found that moderate levels of NAD+ can activate specific enzymes called SIRT1 and SIRT3. This process improves how mitochondria generate energy and lowers oxidative stress that damages cells. It also encourages muscle stem cells to grow and turn into new muscle tissue. However, too much NAD+ signaling can have the opposite effect. High levels might activate a different enzyme, SIRT2, which stops muscle stem cells from dividing and causes them to run out of energy. This dual nature means the benefits depend on keeping levels balanced. The field currently has some inconsistencies, so more work is needed to confirm these results in people. Researchers are developing therapies based on this framework to treat sarcopenia.