Which Season has Greater Shedding?
Do humans really shed different amounts of hair at different times of the year? That answer, in several studies, has been a resounding yes.
Studies to date would suggest that humans tend to shed the most in late Summer and early Fall. That's the seasonal time period whereby humans experience the greatest daily hair shedding. Seasonal shedding is one type of “telogen effluvium.”
Some studies have suggested that another important wave of increased shedding occurs in the Spring, whereas other studies have suggested Spring is distant fourth place (behind Fall and Winter). Seasonal shedding is important to remember for a few reasons.
First, if a patient with pre-existing hair loss is experiencing more shedding in the late Summer and early Fall it may or may not be that their underlying condition is getting worse. The increased shedding may simply be a result of seasonal shedding. This of course requires careful scalp examination and review of the patient’s details. Furthermore, if one starts a new treatment in Fall and notices by early Spring that shedding is less and density is better... one must ask if the treatment was responsible for the improvement or whether the hair have just gotten better anyways on account of the late Summer/Fall seasonal shedding coming to an end.
Courtois M et al. Periodicity in the growth and shedding of hair. Br J Dermatol 1996; 134;47-54.
Hsiang et al. British Journal Dermatology 2017.
Kunz M et al. Seasonality of hair shedding in healthy women complaining of hair loss. Dermatology 2009; 219: 105-10.
Randall CA and Ebling EJG. Seasonal changes in human hair growth. Br J Dermatol 1991; 124: 146-51.
Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Whistler office at 604.283.1887