Through this section, the Scientific Committee wants to provide practical, reliable and useful information to anyone who wants to learn more about hair.
Hair represent a fascinating and still largely unknown world. For human being, hair have a deep symbolic value: their function is to be seen and “admired”. From this point of view, they are a real “organ” of our body, perhaps not of vital importance, but it is surely essential to our aesthetic and psychological wellness. Recent studies confirm that hair’s problems, and in particular the risk of “thinning”, cause anxiety and depression in a significant number of subjects.
Dealing with these problems means to solve an esthetic problem, but, most of all, to improve the subject’s quality of life. In effect, almost in all societies and in many historical periods, the hair has played an important role in the definition of the person, not only in aesthetical terms: hair are very important on the image that each person has of itself and transmits to others.
At first sight, both the hair’s appearance and the hairstyle reveal the attention that each person devotes to himself and to his own lifestyle. With a different hairstyle, a person can change his face and often also the impression that others have about him – and it’s not just a metaphor: to describe or to recognize a person, in 90% of the cases, everything starts from the color, the type or the style of the hair.
Sociologists talk about “Language of Hair”: hair can send messages, can reveal ideas and ambitions. They help to define our personality or, at least, this is the impression that whoever looks at us has.
Why humans care so much about their hair? And why they suffer for them? The different length between male and female hair is a part of our cultural heritage but it has also biological reasons. Although their growth in length occurs in both sexes, nearly at the same speed, in a male there is a change of hair with a double or triple speed in comparison with the female one: usually the Anagen phase of men’s hair lasts about 3 years, while in women it lasts between 6 and 10 years. Men’s hair falls at a theoretical length of about 30-35 cm, while that of the women can reach 100-120 cm.
For this reason, in nature, hair length is an important attribute of sexual dimorphism: ancestrally we are used to consider that if a human being has long hair is female and if he has short hair is male. And if there are no more hair? In this case, there is a sort of regression to a condition, such as childhood, in which the two roles are not yet well separated, including all the rights and powers that they involve.
Therefore, hair loss can be unconsciously experienced by men as a loss of virility or castration, and by women as a loss of femininity.
Almost in all human cultures, hair are often considered symbol of power, energy, fertility and virility. Let’s think about the wonderful curly wig of King Louis XIV, or about the fact that the epithets “Caesar”, “Kaiser”, “Tsar”, used for kings and leaders along different centuries, have also etymological implications referring to long hair to cut. In western culture, a large quantity of hair represented an indispensable asset for the power of a sovereign.
For a long time, the scalp has been an expression of the warrior’s value, an evidence of courage in battle, a tangible sign of a obtained revenge. With the Christian religion tonsure became a common practice for monks, in order to become sexually unattractive and to express humility, obedience and detachment from worldly goods. Instead the obligation of haircut has always been a sign of deep disgust: the ancient Romans cut the hair of prisoners, adulterers and traitors. Nowadays, in the collective consciousness, baldness also gives an idea of premature aging and an explicit sign of decline, and it is often a reason of personal insecurity for social integration.
The hair is a “dead” structure, constituted by fully keratinized cells that lost their nucleus and their vital functions. These cells contain high concentrations of a very strong fibrous protein, the keratin. The hair is produced by the final hair follicle, a specialized organ that lies in the thickness of the skin and that is situated all over the body, except in the palmar and plantar regions. Each follicle is divided into the upper portion (permanent) and in the inferior one (dynamic). Sebaceous gland blooms in the upper portion of the follicle.
This gland produces sebum, which reaches the skin’s surface along with the hair. The lower portion of the follicle instead contains the hair matrix and goes through profound changes during the life cycle. By multiplying and maturing, the cells of the matrix give rise to the hair shaft and to the sheaths that surround it.
Hair shaft is composed by 3 layers: cuticle, cortex and marrow.
Cuticle is the outermost layer and it is formed by flattened overlapping cells. Cuticle protects the shaft from the environment and its integrity is very important for the hair’s health.
Cortex is situated under the cuticle and it is the hair’s thickest part, which defines the form and texture of the hair. The hair’s inner cortex contains a set of macro-fibrils oriented in parallel to the fiber. The macro-fibrils are composed by micro-fibrils cemented to each other by a high sulfuric matrix. The micro-fibrils are made of proto-fibrils (smaller fibrils) arranged in a ring structure in groups of 9, with two central proto-fibrils.
Some hair, especially white ones, contain a thin inner layer, the marrow. The different speed of keratinization (the process that transforms proteins, making them tougher) is very important to understand what are the difficulties to restructure human hair that have cuticles affected by colors, perms, alkaline shampoos and/or automatic stress. In fact, a hair product is assimilated by the three layers of the cuticle at different times, and in order to obtain satisfying results, both in the cuticle and the cortex, it is necessary to use particular and sophisticated treatments.
Hair thickness is subjective and it is influenced by genetic and racial features. For example, the hair of Nordic populations are much thinner in comparison to those of the Mediterranean ones, while Asian races usually have thicker hair. The hair follicle does not produce hair constantly, the production is cyclical and it is characterized by periods of activity alternated to periods of rest. The follicles’ activity is not synchronous and each follicle works independently.
Follicles are usually in the scalp: about 90% in phase of activity and about 10% in phase of rest. This explains why, in normal physiological conditions, hair fall a little bit every day and not all at once, as it happends for other mammals, where the timing of the cycle causes the change of all hair at the same time during the molt. Hair life cycle is made by 3 phases: Anagen – Catagen – Telogen
– Anagen – growth phase
It is the longest phase of hair life cycle. Its duration defines the length of the hair: the hair grows on average 1 cm each month. The Anagen phase during which the hair tends to elongate more is called Metanagen. At the level of the scalp, the Anagen phase lasts from 3 to 7 years, and is mainly regulated by genetic factors; in several subjects, the hair can become longer than 1 meter if they are not cut, in other cases they reach the shoulders. Hair are subject to a physiological replacement every 3-7 years: when an “old” hair falls, it is replaced by a new one (“young” hair). The Anagen phase is longer in patients of Asian race and in women, and over the years the duration of this phase is lower with the consequence that also the hair length is reduced.
– Catagen – transition phase
It is a very short phase that lasts 3-4 weeks. In this phase, the hair’s matrix stops its activity and the follicle returns up to the most superficial part of the skin, where it will spend his resting phase; in other words, the follicle regresses with its progressive constriction towards the surface.
– Telogen – resting phase
It has a fixed duration of about 3 months in all follicles. During Telogen phase, the hair’s matrix disappears and the follicle stops its activity. However, the hair does not fall, but it remains anchored to the follicle and then it falls at the end of Telogen, when the follicle starts again its activity and produces a new hair that, growing up, pushes out the old one.
If the hair in resting phase is removed mechanically, the follicle stops his “rest” and begins early a new Anagen phase. During Telogen phase, the hair is easily recognizable because, when observed under the microscope, it presents different colors compared to the Anagen.
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