Mitochondria, our “power plants,” are the main producers of ATP. However, this process is not perfect. As a byproduct of energy production, mitochondria generate small amounts of reactive oxygen species (ROS), also known as free radicals. These unstable molecules can damage a cell’s DNA, proteins, and lipids.

In youth, our bodies have highly efficient antioxidant defense systems that neutralize most of these free radicals. But as we age, this delicate balance breaks down: free radical production increases, and defense systems become less effective.

This is where the cycle of mitochondrial aging begins:

• Damage to Mitochondrial DNA (mtDNA): mtDNA is particularly vulnerable to free radicals. Unlike nuclear DNA, mtDNA is not protected by proteins and has fewer repair mechanisms. Over time, accumulated mtDNA damage leads to mutations that impair mitochondria’s ability to produce energy.

• Reduced Efficiency: These mutations make mitochondria less efficient, resulting in reduced ATP production and even greater free radical generation. This creates a vicious cycle — more mitochondrial damage leads to more free radicals, which cause further damage.

• Cell Death: Over time, the damage becomes so severe that the cell can no longer maintain normal function and enters a programmed cell death process called apoptosis. The loss of cells, especially in energy-demanding tissues such as the brain, heart, and muscles, is a key feature of aging.