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Abstract
Aging is a natural and complex process that reverses biological characteristics acquired during development and leads to cellular death. Skin aging begins with a redistribution of fat, a decreased dermal elasticity and a loss of bone mass resulting in gravitational changes such as enhanced nasolabial fold. It continues with a progressive impairment of the regeneration of connective tissue components such as collagen and hyaluronate. Finally, the aging skin loses its immunological defenses and its capacity to repair cellular injury.Besides intrinsic aging, the predominant environmental factor that accelerates skin aging is ultraviolet (UV) irradiation from the sun. This sun-induced skin aging, called photoaging (or premature aging) is a cumulative process that depends primarily on the degree of sun exposure and skin phototype (Sorg et al.,2005).