Daily hair loss, is it really 100 hairs per day?

It is generally publicized that it is normal that a person can lose 100 hair a day on average.  Other say that 100 hair a day is a lot and a normal loss is 50 hair/day or even less (20-30 hair/day) and that 100 hair/day is a sign of balding.  Please can you advise if there were any trial to check how many hair on average a person really lose a day or if the 100 hair a day is based only on assumptions regarding number of hair in scalp and 10% in resting phase. Is this assumption of 100 hair/day credible and sure science.  All the best and thank you for everything

Daily hair loss is part of the hair growth cycle.  Hair essentially goes through two cycles. The Anagen Phase is the growth part of the cycle and it averages about three years. However, it often decreases with age and could be two or three years or even less the older you get. The second phase is called the Telogen Phase and it is the “rest” part of the cycle. The hair falls out while the hair root regenerates into a new hair that will regrow after about six months.

In a typical Caucasian who has 100,000 hairs on the head, assuming that the hair growth cycle lasts three years, divide number of hairs on the head by 1095 days and you come up with 91 hairs lost per day. In Asians with 80,000 hairs on their head, the number of hairs lost per day equals 80 percent of Caucasian numbers or 73 hairs per day, again assuming a 3 year growth cycle. A three year hair cycle, which may not be the case in older people, may be reduced, say two years instead of three years. Then the Caucasian hair loss per day would be closer to 150 hairs per day and the Asian hair loss per day would be about 120 hairs per day.