NAD+

NAD+ acts as a critical coenzyme in redox reactions, accepting or donating electrons in metabolic pathways such as glycolysis, fatty acid oxidation, and the citric acid cycle. It is a substrate for sirtuins, NAD+-dependent deacetylases that remove acetyl groups from proteins and regulate gene expression. Sirtuins are involved in DNA repair, stress resistance, inflammation, and metabolic homeostasis, which helps explain several observed NAD+ benefits.

NAD+ is also consumed by poly(ADP-ribose) polymerases (PARPs) in response to DNA damage. PARPs help repair DNA but can deplete NAD+ levels if overactivated. CD38, an enzyme that generates cyclic ADP-ribose, also consumes NAD+.

NAD+ can be synthesized de novo from the amino acid tryptophan or through salvage pathways using precursors like nicotinic acid, nicotinamide, and nicotinamide riboside. Supplementing with these precursors can boost NAD+ levels.
 

Research suggests that maintaining optimal NAD+ levels may provide the following NAD+ benefits, helping explain what NAD+ is used for in clinical and research contexts

• Longevity: Studies in yeast, worms, and mice have shown that boosting NAD+ levels can extend lifespan. Sirtuins, which are NAD+-dependent, are linked to increased longevity in various organisms.
• Metabolic health:  NAD+ is crucial for energy metabolism. Increasing NAD+ levels can improve mitochondrial function, glucose metabolism, and insulin sensitivity. These NAD+ benefits may help protect against obesity, type 2 diabetes, and metabolic syndrome.
• Cardiovascular health: NAD+ precursors have shown potential benefits for cardiovascular health, such as improving blood pressure, reducing inflammation, and protecting against oxidative stress.
• Neurological health: NAD+ is important for neuronal function and energy metabolism in the brain. Boosting NAD+ levels may help protect against age-related cognitive decline, Alzheimer's disease, and Parkinson's disease.
• DNA repair: NAD+ is a substrate for PARPs, which are involved in repairing DNA damage. Maintaining adequate NAD+ levels may support DNA repair mechanisms and genomic stability.
• Inflammation: Sirtuins, which are NAD+-dependent, have anti-inflammatory effects. Increasing NAD+ levels may help regulate inflammation and protect against chronic inflammatory diseases.

NAD+ precursors like nicotinic acid, nicotinamide, and nicotinamide riboside are generally well-tolerated. However, high doses of nicotinic acid can cause flushing, itching, and gastrointestinal discomfort. Nicotinamide at high doses may also cause gastrointestinal side effects and liver toxicity.

NAD+ is a vital coenzyme involved in energy metabolism, DNA repair, cell signaling, and aging. NAD+ levels can be supported either directly through NAD+ injection or indirectly through NAD+ supplements that contain precursors used by the body to synthesize NAD+. Maintaining optimal NAD+ levels through supplementation with precursors or other means may provide benefits for longevity, metabolic health, cardiovascular health, neurological function, DNA repair, and inflammation. While NAD+ precursors are generally safe, it is important to use them under medical supervision and be aware of potential side effects at high doses.

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