Autophagy ('self-eating') is the cellular process of breaking down damaged organelles, misfolded proteins, and other debris, then recycling the components.
Mechanism: Triggered by nutrient scarcity (fasting), exercise, hypoxia, and rapamycin/mTOR inhibition. Damaged mitochondria are specifically targeted via mitophagy. Declines with age, contributing to senescent cell accumulation.
Use case: Promoted via intermittent fasting (>16h), prolonged fasts, exercise (especially fasted), and compounds like spermidine and resveratrol. Rapamycin is the most potent inducer but is a prescription.
Caveats: Autophagy isn't always beneficial. Chronic activation can be catabolic. Cycle it. Don't chase autophagy during heavy growth phases.