**Abstract**

The hair follicle is the unique organ that has the capacity of undergoing cyclic transformations following periods of growth (anagen), regression (catagen), and rest (telogen) regenerating itself to restart the cycle. The dynamic capacity of hair to growth and rest enables mammals to control hair growth and length in different body side and to change their coats. Unlike what is observed in many animals in which the pelage synchronously passes from one phase of the cycle to other all stages of growth cycle are simultaneously found in the human pelage, the growth pattern is a mosaic where the hair cycling staging of one hair root is completely independent of it nearest hair follicle, meaning that each follicular unit (FU) can contain follicles in different stages at any given time. A variety of factors, such as nutritional status, hormones, exposure to radiations, chemotherapy or radiotherapy, environmental pollution or drugs may affect hair growth, and affects the number of hairs, this progressive hair loss has a cosmetic and social impact that often significantly affects social and psychological well-being of the patient that suffers from this hair loss. Although a number of therapies, such as finasteride and minoxidil, are approved medications, a wide variety of classes of phytochemicals and natural products, including those present in ginseng are being testing. The purpose of this chapter is to focus on study the potential of ginseng and its metabolites in hair loss.

**Keywords:** Ginseng, Hair, Hair Follicle, Hair growth, Hair Viability

### **1. Introduction**

#### **1.1 Hair structure**

Hair is made of several proteins, the principal protein that compound the fibrous structure of the hair is keratin, in addition to keratin, which has a high content of the amino acid cysteine, the hair also contains water, lipids, minerals, and the pigment melanin.

The hair shaft (the visible fiber that is growth above the skin), is a fiber with a variety of color depending of the melanin content that pigmented the keratin fiber. The dermal element in the hair follicle is the dermal papilla, which is majorly former by fibroblast cells, this dermal element controls the hair cycle.

The fiber of the hair, the hair shaft, grows from the hair follicle which is a tubular structure that forms a bulb around the matrix of the hair bulb, specialized dermal

stem cell and different types of keratinocytes, from this hair bulb that form the dermal papilla the hair shaft growth by division of proliferative cells, thus cells goes to a process of differentiated, keratinized, and pigmented in the hair follicle to form the hair shaft in a cycling manner. The diameter of the hair shaft is directly related to the size of the papilla, and allows us to define the miniaturized hairs and normal hair.

The hair structure is composed by concentric layers that forms the hair follicle, the medulla which is the center is includes the cortex and outwards the cuticle of the cortex, and is surrounded by the inner and outer root sheath, and all the mini-organ is surrounded by connective tissue.

#### **1.2 Hair function**

The functional aspect of hair is not only to protect from radiation, heat or cold and any extern agent but also contribute to the appearance and personality. The loss of the hair contributes to psychological, social and psychosocial problems, generating a cosmetic and social impact in our society.

#### **1.3 Hair cycle**

The hair follicle has the unique capacity of undergoing periods of growth (anagen), regression (catagen), and rest (telogen and exogen) before regenerating itself to restart the cycle [1–4] (**Figure 1**). This dynamic cycling capacity enables mammals to change their coats, and for hair length to be controlled on different body sites [5].

Unlike what is observed in many animals in which the pelage synchronously passes from one phase of the cycle to other all stages of growth cycle are simultaneously found in the human, the growth pattern is a mosaic where the hair cycling staging of one hair root is completely independent of it nearest hair follicle, meaning that each follicular unit (FU) can contain follicles in different stages at any given time. In healthy individuals, 80–90% of follicles are in the anagen phase, 1–2% in the catagen phase, and 10–15% in the telogen phase [6]. The hair grows around one centimeter a month, and has a variable growth speed being faster in the summer than in winter. The growth phase, or anagen phase, lasts an average of 3–5 years. This normal hair-growth cycle can be modified or by internal or external factors such as hormones, stress, sun, disease, exposure to environmental pollution, drugs and smoking. This changes in the growth cycle and quality of hair can leads to hair loss by a shortening of the anagen phase, a premature ingression of the catagen phase, the prolongation of the telogen phase or a loss of the hair

#### **Figure 1.**

*Hair cycle stages scheme, phase of growth (anagen), regression (catagen), and rest (telogen) before regenerating itself to restart the cycle.*

follicle function [6, 7]. Common hair loss is medically named as alopecia, and can be suffer by men and women.
