Aging Influences on Hair

Analysis of Acidic and Basic Groups in Whole Human Hair 

Alterations to the fibers that affect the apparent frequency of acidic or basic groups, such as hydrolysis, susceptibility to hydrolysis, or the introduction of sulfonic acid groups [24, 66], can affect the acid- and/or basecombining capacity of hair. Therefore, permanent-waving and especially bleaching can affect these titration parameters [8]. The effects of cosmetic treatments and environment on these parameters are described in detail in Chapter 5. 

As a person ages, hormonal changes contribute to changes in the hair. The more obvious ones are hair thinning, hair graying, and dryness of the scalp and the hair. 

The anagen period not only controls hair fiber thickness but it also controls the maximum length that hair can grow. Therefore, one can expect a 

Aging of individual hair fibers on one s head generally results in a gradual degradation of the scales through cuticle fragmentation described in detail in Chapter 5. This process is related to the actual age of the individual hair on the scalp (or its residence time) more than to the age of the individual and will not be described further here. 

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Aging Influences on Hair 77 Hair Straightened with Alkaline Straighteners... 

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