Written in SCIENCE he
The growth cycle of hair It has three phases: anagen or growth, catagen the transition between anagen and telogen and telogen or rest. The length of the hair is proportional to the duration of the growth phase which lasts from two to six years.
The longer this phase lasts, the more hair will grow, and “this depends on genetic, nutritional, hormonal and metabolic factors,” explains Javier Olalquiaga, head of the clinic’s dermatology service. Madrid center.
Elena Roche, specialist of the Hair Medicine Service of the Quirón Hospital of Valenciaclarifies that hair growth depends on the level of irrigation bloodtrace elements, amino acids and vitamins.
How much growth per day, month and year?
According to him, the hair It grows about 0.4 millimeters per day, one centimeter per month and about 15 centimeters per year. “On the scalp and, in the absence of pathology, there is approximately 85 percent of the hair in the anagen phase, 14 percent in the catagen phase and 1 percent in the catagen phase.” So, for example, hair grows faster on the crown of the head than in the temporal region.
Growth is not homogeneous, since in a certain area of the scalp there will always be a percentage of hair in each phase of the cycle.
Olalquiaga points out situations in which the amount of hair increases during the resting phase:
• Thyroid diseases
• Iron deficiency
• Hypozinchemia
• Febrile episodes
• Diets
• After delivery
Can it grow faster?
Roche reveals that the growth phase can be lengthened with minoxidil. It inhibits the action of the testosterone metabolite at the scalp, thus reversing the reduction of follicles, a process that causes baldness. This denies that more or less maintenance of the outer layer affects the growth of the hair bulb.
And Olalquiaga explains it: “the growth occurs several millimeters deep.” Roche denies that cutting or shaving your hair will make it healthier and stronger. On the other hand, it grows more slowly when there are nutritional deficiencies or diseases metabolic.