Autumn hair shedding: why it happens and when to worry

Yes, on average. In a study from Sheffield, UK, researchers followed 14 healthy men every 28 days for 18 months. The share of scalp follicles in the growing phase peaked at over 90% in March and fell steadily to its lowest point in September. Shed hairs peaked around August and September at about 60 a day, more than double the number in the previous winter^[1].

A larger study looked at 823 otherwise healthy women who came to a hair clinic over six years. Their hair samples showed the highest share of resting hairs in summer, a smaller peak in spring and the lowest rate in late winter^[2]. Because resting hairs fall out some weeks later, a summer peak in resting hairs shows up as more hair in the shower in late summer and autumn.

Each hair follicle runs its own cycle: a long growing phase (anagen), a short transition, and a resting phase (telogen), after which the hair falls out and a new one starts. At any moment most follicles are growing. When more of them enter the resting phase at the same time, more hairs are shed together a little later.

Why the cycle shifts with the seasons in humans is not fully understood. What matters in practice is the timing: the shedding you see in September reflects what your follicles did in the summer.

Losing 50 to 100 hairs a day is normal, according to the NHS and the American Academy of Dermatology (both checked 2026-10-18). Long hair makes the same number look larger, and hairs collect over the days between washes, so a wash day can look alarming even when the daily total is normal.

Telogen effluvium is a separate condition that follows a trigger. The American Academy of Dermatology lists high fever, surgery, childbirth, losing 20 pounds (about 9 kg) or more, intense stress and stopping birth-control pills as triggers, and says most people notice the shedding a few months after the event. A review describes a high rate of remission once the trigger has passed^[3]. Pattern hair loss is different: under magnification it shows hairs of very different thickness, because follicles are shrinking^[4].

• Keep washing and brushing as usual. Hairs in the resting phase will fall out anyway; washing less only saves them for the next wash.
• Look back three months. A fever, an operation, a strict diet or a stressful period may explain a heavier shed than usual.
• Think about iron. The NHS lists iron deficiency among the causes of temporary hair loss; heavy periods or a restrictive diet make a blood test worthwhile before buying supplements.
• Take photos of your parting and crown in the same light each month. They show the difference between a passing shed and thinning.

• Shedding is still heavy after two or three months.
• You see round bald patches, or eyebrows and eyelashes are thinning too.
• Your parting is wider or your temples are receding.
• The scalp is red, scaly, itchy, painful or burning.
• You also feel unusually tired, have gained or lost weight, or have heavy periods.
• Pattern hair loss runs in your family and you want to start treatment early.

A scalp check is quick: questions, a pull test and trichoscopy, as described in hair loss diagnosis at a Seoul clinic.

If you have pattern hair loss, the right time to start is when it is diagnosed, whatever the month. Take progress photos at the planned review points, with the same light, angle and hairstyle. Keep the season in mind when you compare them: in the study of 823 women, the share of resting hairs was highest in summer and lowest in late winter^[2].

Autumn is also a popular time to visit Seoul. If you want a scalp check during the trip, treatment on a short trip explains how to fit it into a few days.