Healthy hair structure is characteriszed by the cuticle closely surrounding the cortex. The closer it surrounds the cortex, the better the hair is protected from harmful external influences. This picture shows an electron microscopic scan of a healthy hair.
If hair is damaged, the cuticle is open and rough, and harmful influences can penetrate unhindered into the interior of the hair. If the damage is severe and exogenous, the hair may ultimately break.
While the causes of alopecia are systemic, the origins of damage to the hair structure – insofar as they are not of genetic cause – lie exclusively in external influences, which can be mechanical, chemical or physical.
- Mechanical (e.g. combing, extreme brushing, back-combing, fastening with elastic bands, etc.)
- Chemical (e.g. tints, bleaches, dyes, perms)
- Physical effects (e.g. excessive heat from haidryers, intensive exposure to sun or UV rays)
Weather influences on hair structure
Even weather can influence hair structure. Hair that is in good condition near the scalp surface changes towards its end and shows marked erosion damage.
Hair growth phases
Hair growth is a cyclic and asynchronous process. Healthy hair undergoes three phases that re-occur in cycles. In people with healthy hair about 85% of hairs are in the anagen, 1% in the catagen, and 14% in the telogen phases at any given time.