Myth: Brushing your hair 100 strokes a night is good for it.
May 23rd 2017 by Tony Maleedy.
No it’s not. It can be terrible, especially for longer hair. As hair grows longer it becomes drier and more fragile, brushing causes it to split and break. It’s better to use a good quality wide-tooth comb which is kinder to the hair. When combing (or if you really have to) brushing longer hair, always start at the ends of your hair and work backwards, this reduces the chances of your hair knotting at the ends.
The science bit:
As a brush passes over the hair the bristles bend and an increased force puts more pressure on the hair causing splitting and breakage. Also, when using a brush the hand is less sensitive to resistance than when a comb is used, so a brush tends to force apart any tangled hairs causing them to split and break. In contrast to this a wide-tooth comb allows any tangles to be gently eased out of the hair, dramatically reducing hair splitting and breakage.