It’s important to understand the Normal hair growth cycle before knowing how hair loss occurs. The hair follicle (root) is an anatomical structure that produces & extrude (push out) a hair strand. Hair grows in a continuous cyclical pattern of Growth, Degradation & Rest known as the “Hair growth cycle”. There are three phases of Hair Growth cycle:
- Anagen/ Growing phase
- Catagen/ Degradation phase
- Telogen/ Resting phase
About 90 percent of the hair on your scalp is growing at any one time. This Anagen (Hair growing) phase lasts for a period of 2-6 years. The hair grows approximately 1 centimeter per month during this phase. This is followed by a brief period of Catagen (degradation) phase, of 2-4 weeks, in which the follicle is almost completely degraded. The Telogen(resting) phase then begins and last for 2-4mnths. About 10 percent of the hair on your scalp, at any one time, is in a resting phase.. After 3 to 4 months, the resting hair falls out and new hair starts to grow in its place. On average 50-100 resting hairs are shed every day. This is the Normal hair fall seen in everyday life. These hairs will re grow.
A number of factors can affect the Normal hair growth cycle & cause temporary/ Permanent hair loss including Hormonal & nutritional factors, Stress, Thyroid disorder, skin diseases, medications, radiations, exposure to chemicals.
Male Hair Loss Treatment
Male pattern hair loss (Androgenic Alopecia) is an inherited condition in which men may begin loosing hair any time after puberty. Androgens ( Dihydro- testosterone, Testosterone) are necessary for development of Male pattern baldness. The gene for male pattern baldness can be inherited from either the mother or father’s side. The first sign is usually recession of Temporal hair line .The density of hair decreases with time, but there is no way to predict what pattern of hair loss a youth with early male pattern hair loss will eventually assume. In general, the earlier age you began to lose hair the severe is going to be the hair loss.
If the androgen are present in normal amount & gene for hair loss is there, male pattern hair loss will occur. Receptors are there on cells that bind to androgen. The greatest affinity of these receptor is to Dihydro testosterone (DHT) followed by Testosterone, estrogen and progesterone. Testosterone is converted to Dihydro testosterone by enzyme 5 alpha reductase. After binding to the receptor, DHT goes inside the cell and alters the production of protein by the DNA in the nucleus. Ultimately the growth of Hair follicle ceases.
The hair growth cycle is affected in that the percentage of hairs in the Anagen(growth) phase and the duration of growth phase diminishes resulting in shorter hairs. More hairs are there in Telogen(Resting) phase and these are subjected to fall more aggressively. The hair strand becomes progressively miniaturized, smaller in diameter and length. All the hairs in the affected area will become gradually involved in the process , and will eventually cover the area with fine (villus) hairs. Pigment (color) production is also terminated with this process. The light color thin hairs cause the area initially to appear less dense/sparse. Involved area may completely loose all follicles over time and appear Bald.
Norwood’s Classification of Male pattern Baldness