Care of the hair and care of the scalp skin may appear separate, but are actually intertwined because hair grows from beneath the skin. The living parts of hair (hair follicle, hair root, root sheath, and sebaceous gland) are beneath the skin, while the actual hair shaft which emerges (the cuticle which covers the cortex and medulla) has no living processes. Damage or changes made to the visible hair shaft cannot be repaired by a biological process, though much can be done to manage hair and ensure that the cuticle remains intact.
One way to distribute the hair’s natural oils through the hair is by brushing with a natural bristle brush. The natural bristles effectively move the oil from the scalp through to the hair’s mid-lengths and ends, nourishing these parts of the hair. Brushing the scalp also stimulates the sebaceous gland, which in turn produces more sebum. When sebum and sweat combine on the scalp surface, they help to create the acid mantle, which is the skin’s own protective layer.