Encyclopedia
Reference entry
Physiology
Hair cycle
The growth, transition and resting phases every follicle moves through.
Soumm · Physiology
Definition
Each follicle cycles through anagen (growth), catagen (transition) and telogen (rest), before the hair is shed and the cycle begins again.
Because anagen lasts years and telogen months, only a minority of hairs are resting at any time.
Why it matters
The cycle explains why change is slow and why shedding today may reflect an event months ago.
See also: Telogen Effluvium, Shedding.
A note on evidence
Hair responds to many things at once: sleep, nutrition, hormonal changes, scalp condition and stress among them. Published here for education only; individual concerns should be discussed with a qualified healthcare professional.