Eighty-eight percent of hair is made up of proteins, known as keratin. Keratin is composed of polypeptide chains, two amino acids joined together, according to the Salon Web website. Hair grows in cycles and each hair goes through three phases. "The Control of Hair Growth" labels these phases as anagen, catagen and telogen. The first phase, anagen, is the active part of hair growing and can last from two to six years depending on the skin of each individual. Once the anagen phase is complete, hair goes into the second phase, catagen, which only lasts two to three weeks. In the catagen phase, the cells stop dividing and the hair becomes keratin. The last phase of hair growth is telogen, where the matured hair falls out. A new hair starts to grow and the cycle repeats.
N-WASP
According to the Science Daily website, researchers from Massachusetts General Hospital determined that the protein N-WASP plays a key role in the cycle of hair follicles. The study, which was published in the 2010 issue of the "Journal of Clinical Investigation," and involved cytoskeleton reorganization, which is regulated by the proteins Cdc42 and Rac1. The researchers found that N-WASP is critical for cells in the outer layer of the skin and for hair growth. The importance of this protein in hair growth is for the growing cycle as well as the maintenance and differentiation of the hair follicle cells.
VEGF
A study that was published in the 2001 issue of the "Journal of Clinical Investigation" examined the cyclical changes in hair growth and the importance of the protein VEGF in relation to the vascularization, or formation of blood vessels and capillaries, of the hair follicle. The study was performed on mice and testing occurred during the anagen phase. Observations were made during all phases of hair growth.
Results concluded that VEGF helps to increase the size of hair follicles and hair shafts, creating thicker hair. Blocking the VEGF protein caused retardation in hair growth and a reduction in hair follicle size.
Procyanidin
In the 1999 issue of the "Journal of Investigative Dermatology," a study was published regarding the protein procyanidin and the promotion of hair growth. The study was performed on mice and the procyanidin was extracted from apple juice. Results indicate that procyanidin directly affects the growth of epithelial cells in the skin. The researchers were able to demonstrate that procyanidin had both hair epithelial growth promoting activity and hair growing activity. Compared to other examined compounds, procyanidin was the only compound to show greater than 300 percent growth promoting activity on hair epithelial cells.
References
- Salon Web: The Structure of Your Hair
- Science Daily: Protein N-WASP Helps Hair Growth
- Dermatology Online Journal: The Control of Hair Growth
- The Journal of Clinical Investigation: Control of Hair Growth and Follicle Size by VEGF-Mediated Angiogenesis
- Journal of Investigative Dermatology: Procyanidin Oligomers Selectively and Intensively Promote Proliferation of Mouse Hair Epithelial Cells In Vitro and Activate Hair Follicle Growth In Vivo
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