Cortisol actually breaks down tissue, including skin. It also can wreak havoc on numerous bodily functions. As your body’s chief, and powerful, stress hormone, it tells your body to do three things: increase your appetite; stock up on more fat; and break down materials that can be used for quick forms of energy, including muscle.
Sounds opposite to what you’d like to have happen, but that’s how your body naturally responds to stress. It automatically goes into a protectionist mode. You see, cortisol is your primary catabolic hormone, meaning it halts growth and reduces cellular synthesis (as opposed to increasing cell production and metabolism), causes muscles to break down, and assembles fat. It thinks the body won’t see food again for a while or that we need an ample supply of fuel to get through a rough patch.
From The Mind-Beauty Connection: 9 Days to Less Stress, Gorgeous Skin, and a Whole New You by Amy Wechsler.