Well, the question could be reframed as
'when does the falling of hair be of concern?' This is because,
medically, some amount of hair falling has been considered 'normal'.
Hair being an appendage of the body like nails, they grow and fall
constantly, in varying degree.
How Much of Hair Falling Per Day is
Medically speaking, for an adult, about 40 to 80 hair falling a day is
considered within a normal range. It simply means that one may not
consider getting treated for it if this is the case. However, it is also
important that if one observes sudden increase of hair falling even
within the normal range, it calls for medical attention and evaluation.
Again, if one has hair falling within normal range but if they fall from
the roots amounting to a definite reduction in the quantum of the total
hair on the scalp, it calls for appropriate treatment. In any case,
consistent hair falling over 80 a day and/or reduced hair quantum needs
to be evaluated for treatment. Localized hair falling, leading to even
tiny . hairless spot (alopecia) should always be studied and
Normal growth cycle of
Anagen/ The growing phase:
In this phase, the hair grows rapidly from the follicle.
This phase usually lasts for about 1000 days; however, it
may range form 2 to 6 years. Longer the anagen phase, the
longer the hair will grow.
Catagen/ Hair growth stoppage:
This is a regressive phase lasting for about 2 weeks. In
this phase, the hair stops growing, the follicle shrinks and
part of it may die.
Telogen/ Resting phase:
This is the final resting end phase of hair growth cycle; no
further change occurs now. This phase may last for about 2
to 4 months.
Later on, the hair follicle
becomes active again developing new hair and forcing old
Telogen hair out. At any given time, 90% of hair is in
Anagen phase and 10% in Telogen phase. A reversal of the
ratio results in thinning of hair.