UV exposure, toxic exposure, chronic inflammation, poor posture, weight fluctuations, hormonal changes and mental-emotional stress can age your skin, causing the aged sagging appearance.

Reactive oxygen species are unstable molecules with an extra electron that can damage cellular components, including the collagen and elastin fibers inside your skin cells. They also prevent your mitochondria from being able to efficiently produce energy (ATP) that fuels skin repair and protection. 

When reactive oxygen species exceed antioxidant capacity, you have oxidative stress.

The skin starts to appear aged when the oxidative stress exceeds its natural ability to neutralize the reactive oxygen species and self-repair the damages. As the rest of the body also ages, it has less energy and nutrients to supply from inside the body, causing the skin to feel dry and thin. All of this results in fine lines, wrinkles, age spots, and sagging, crepey skin.

In contrast, youthful skin cells have sufficient cellular antioxidants and robust mitochondria that produce enough energy to self-repair.