Through thick and thin…
The length of hair that you are able to grow is controlled by the duration of the growing phase, which varies between individuals. We all lose some hair naturally each day when we brush, comb or wash it and as long as new hairs are being produced at the same rate as those falling out, there will be no difference in hair volume. However if the rate of shedding exceeds production the net result is hair loss or thinning.
A variety of factors can alter the normal hair growth cycle and cause temporary or permanent hair loss including medication, chemotherapy, exposure to chemicals, hormonal factors, thyroid disease, stress or nutritional factors.