An integrated anti-aging framework targeting NAD<sup>+</sup> homeostasis, mitochondrial quality control, and redox stability: Roles of NMN/NR, PQQ, and EGT.

As the global population ages rapidly, delaying and preventing age-related diseases have become urgent priorities in public health and biomedical research. During aging, mitochondrial dysfunction(definition) is a core molecular hallmark and a common pathogenic mechanism underlying multiple age-related disorders. Age-related mitochondrial dysfunction typically manifests as diminished metabolic capacity, impaired organelle renewal, and disrupted redox homeostasis. These factors interact to form a feedback loop constraining mitochondrial adaptability. Specifically, the interdependent decline in NAD⁺ availability, impaired mitochondrial biogenesis, and excessive oxidative stress render single-pathway interventions ineffective in mitigating systemic functional impairments triggered by aging. To address this complex mechanism, this review presents a novel tri-axis anti-aging model encompassing three key compounds: nicotinamide mononucleotide/nicotinamide riboside (NMN/NR), pyrroloquinoline quinone (PQQ), and l-ergothioneine (EGT). Within this framework, NMN/NR serves as a broad NAD⁺-dependent regulator of mitochondrial homeostasis, with its most immediate effects on metabolic activation, while PQQ and EGT may further strengthen mitochondrial remodeling and redox resilience, respectively. While each compound has distinct functional emphases, they are highly mechanistically coupled, collectively forming a closed-loop network regulating mitochondrial number, function, and homeostasis. This review synthesizes preclinical and emerging clinical evidence supporting the standalone or combined use of NMN/NR, PQQ, and EGT across various diseases. Collectively, by conceptualizing mitochondrial aging as a systemic imbalance rather than isolated molecular defects, this paper highlights a three-axis model of NMN/NR, PQQ, and EGT. This framework offers a theoretical foundation for mitochondrial-targeted anti-aging interventions while laying the groundwork for future clinical research, nutritional interventions, and the development of multi-target combination strategies.