According to research, there are two distinct types of ageing; extrinsic and intrinsic.
Natural or genetically inherited ageing is known as intrinsic ageing. The other type is due to the exposure to the environment and is known as extrinsic ageing.
A common sign of intrinsic ageing of the skin is the appearance of lines and wrinkles. There is no way to entirely avoid them, because as we get older the skin becomes thinner and drier due to loss of collagen and lack of water being held. The intrinsic ageing process is continuous from the mid-20s age range, although the rate is variable and may depend on your genetics.
Collagen is a fibrous protein which is a key constituent of the skin. It makes up 25% of the total proteins in the body and provides support, elasticity and great tensile strength. The onset of the ageing process brings on a decrease in the level of collagen production. Loss of collagen reduces elasticity and cutaneous strength in the dermis of the skin.
Also, as you get older, dead skin does not shed as quickly and the turnover of new skin cell production decreases slightly.
The results of intrinsic ageing are: