Many people notice increased hair shedding in the autumn months and wonder whether something has changed. In fact, seasonal variation in hair loss is a documented phenomenon — not a disorder, but a normal fluctuation in the hair growth cycle that is more pronounced in some individuals than others.
Research has shown that the proportion of scalp hairs in the telogen (resting) phase is higher in late summer and early autumn than at other times of year. The proposed explanation is evolutionary: increased hair growth in the spring and summer, followed by a synchronised shedding event as days shorten, mirrors the seasonal coat changes seen in other mammals.
The result is that many people experience more hair in the shower, on pillows, and in hairbrushes during September, October, and November than at other times of the year. This is entirely normal and the hair regrows over the winter months. The key distinguishing features from pathological hair loss are: the shedding is temporary and resolves within two to three months, and it does not result in visible thinning or pattern change.
If shedding in the autumn months is accompanied by visible changes to hairline or part width, or if it does not resolve by January or February, a clinical assessment is warranted to rule out concurrent androgenetic alopecia or a nutritional deficiency that the seasonal change has unmasked.
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