An Overview of the Skin
Subcutis: The Skin's Fatty Layer
Reduction of tissue in this layer is what causes your skin to sag as well as wrinkle. This layer hosts sweat glands, and fat and collagen cells. The subcutis is responsible for conserving your body's heat and protecting your vital inner organs.
Collagen and Your Skin
Collagen is found in the dermis and is the most abundant protein in the skin, making up 75% of this organ. This is also your fountain of youth. It's responsible for warding off wrinkles and fine lines. Over time, environmental factors and aging diminish your body's ability to produce collagen and can also break down existing collagen.
Your Skin and Elastin
When you hear the word elastin, think elastic. This protein is found with collagen in the dermis, and is responsible for giving structure and support to your skin and organs. As with collagen, elastin is affected by time and the elements. Diminished levels of this protein cause your skin to wrinkle and sag.
Keratin and Your Skin
Keratin is the strongest protein in your skin. It's also dominant in hair and nails. Keratin is what forms the rigidity of your skin.

