Mechanism
Mitochondrial reactive oxygen species (mtROS)
Reference definition for a mitochondrial-biology node.
Definition
Category: Signalling / damage node
Also known as: mtROS, mitochondrial oxidative stress
Mitochondrial reactive oxygen species are by-products of electron leak at the respiratory chain. At low levels they act as signalling molecules (mitohormesis); in excess they damage lipids, proteins, and mtDNA and contribute to age-related vascular and metabolic dysfunction. The mitochondria-targeted antioxidant MitoQ is designed to accumulate in mitochondria and blunt excess mtROS.
Key points
- MitoQ (mitoquinone) is a ubiquinone conjugated to a lipophilic cation so it concentrates at the inner membrane, targeting mtROS specifically.
- The relationship is not 'more antioxidant is always better' — low-level ROS signalling has beneficial (hormetic) roles, and untargeted antioxidants have repeatedly failed in outcome trials.
- Human MitoQ evidence is a small functional-endpoint vascular RCT, not a lifespan study.
Related interventions
Sourcing
Standard mtROS / mitohormesis reviews; Murphy & Smith on targeted antioxidants.
Reference synthesis (tier 4); verification: review_level_2026-07-12.