ANTI AGEING : Why does our skin change when we age? There are three main components of healthy skin COLLAGEN — which provides skin firmness and smoothness (70% of your skin is collagen) ELASTIN — which supplies skin elasticity and rebound HYALURONIC ACID — which keeps the skin hydrated and moist (50% of your body's concentration of HA is in the skin) A decline in your body’s production of these three is what causes dry, dull, wrinkled, and sagging skin.