Genetic Factor and Male Hormone DHT, both are responsible for hair loss. Without genetic susceptibility, hair loss will not occur. If hair loss genes are found on testing, we can say person is susceptible to hair loss, still there is a possibility, the person might not go through hair loss. Its means hair loss genes remain inactivated. If male hormone DHT is absent, hair loss will not happen even in the presence of genetic susceptibility. If hair loss genes are activated in the body and DHT concentration is higher, the hair loss is faster.
When we are born, Male hormone DHT is not present, at the start of puberty around age 10-12, there is surge of all male hormones including DHT, and they reach their highest level by age 18. The male hormones including DHT are essential to transform boy into man. DHT is important for the development of secondary sex characters during the age 10 to 18. Once the secondary sex characters are developed by age 18, we do not need DHT anymore. DHT the useless male hormone after age 18, stays very high during 20's and start declining gradually in 30's and reduced to lowest level in 60's . Hair loss pace is directly tied to the concentration of DHT in the body, higher the DHT, faster is the hair loss.
Once the hair loss gene is activated in 20’s, the DHT concentration is very high at this age, hair loss is the fastest.
On the contrary if hair loss genes get activated in 50’s, the DHT concentration is on the lower side, the hair loss is very gradual.
Once the person has genetic susceptibility, hair loss genes can get activated; age of hair loss gene activation is going to determine the pace of hair loss. At what age hair loss gene get activated, cannot be predicted. Once it get activated , we can predict the course of hair loss depending on the age at which hair loss gene get activated, as the pace of hair loss is directly related to the concentration of DHT, higher the DHT concentration , faster is the progression of hair loss .
Accurate diagnosis of hair loss is only made by examination of hair and by pluck test. Normally 90 % of the hairs on scalp are strong and of same length, while less than 10% of the hairs are of variable lengths (shorter in length). If the strong equal length hair proportion become 80% and 20% hair are of shorter in lengths, it's the start of hair loss.
Pluck Test
Approximately 50 hairs are grasped in a rubber tip surgical clamp and are quickly jerked out of scalp. Normally 90% of the pulled hair bulb depths are average 4 mm and 10% pulled hair depths are average 2 mm. If 20% pulled hair bulbs depth are 2 mm, it's the start of hair loss. Pluck test confirm the hair loss.
Noticeable Hair Loss
Male Hair Loss