People with hair loss loose significantly more than 100 hairs per day. Hair loss is classified as reversible (temporary) and irreversible (permanent) loss.
One of the biological reasons for hair loss is a premature transition from the growing phase to the phase of rest. Another one is the decrease of the hair follicle usually caused hormonally (for men). External factors like insufficient nutrition, stress, medicine or mechanical influences (low quality combs and brushes) can also play an important role.
Reversible hair loss caused by external factors can be suppressed quickly by an adequate treatment. In case of biological reasons the status of the follicle may tell whether the hair loss is reversible or not. Clients with extreme forms of hair loss should contact their doctor.