Daily hair loss normal at 100 hairs/day

A local doctor told me that it’s normal to shed 80-100 hair a day, but hairloss starts to occur when these shed hair are not replaced.,  Is this right?

We all shed about 100 hairs per day and replace that same number. IF you calculate that we have approximately 100,000 hairs on the head (typical Caucasian) and with a 3 year hair cycle between anagen and telogen, the growth cycle in a typical male is about 3- 3 1/2 years.