From the age of thirty, cell turnover starts to slow down which leads to a buildup of dead skin, and it doesn't always slow at the same pace across your face so you end up with patches of dead skin in some areas, causing your complexion to be dull, uneven, and rough.
Ageing skin is associated with a range of cosmetic concerns. The development of dry, dull skin also is common, adding to an overall lack lustre appearance. With ageing, the surface of the skin tends to have a "sallow" appearance- that is, dry, with a slight yellow, lifeless tinge, which results from a slowing down of the metabolic process yielding skin, that does not renew frequently, and looks "sluggish".
Exfoliation is the key to removing dead skin cells that cause your skin to look dull. To force your skin into the habit of faster cell turnover, introduce products containing ingredients such as salicylic acid, retinol, PHA’s, peptides, exfoliating enzymes and growth factors that speed up the process into your daily regimen. One also needs to moisturise your skin on a daily basis and protect the skin from the sun and free radicals by using anti-oxidants and sun protection products.
In addition to dead skin, dull skin is also caused by poor diets high in fat and processed foods. To improve the look of your skin you need to eat more fresh fruits and vegetables and less processed junk food and increase your daily water intake.