Why does skin get drier as we get older?

Aging changes several of the skin's biological functions: sebaceous secretions and therefore the hydrolipidic film decrease, the epidermis becomes thinner, the dermal-epidermal junction becomes flatter, and the major molecules of the dermis (collagen, hyaluronic acid and elastin) decrease. All this results in suffering and fragility, and dryness is a frequent expression of this.