Losing more hair in late summer and autumn is normal: this is seasonal hair shedding, which peaks between September and November and usually lasts 4 to 8 weeks. Stress, on the other hand, can trigger diffuse shedding called telogen effluvium, which starts 2 to 3 months after the stressful event and is usually reversible. Here is how to recognise both types of hair loss, how long they last, what genuinely helps and when it is best to see a doctor.
Seasonal hair loss: which months are affected?
We lose roughly 50 to 100 hairs a day, and that number changes throughout the year. For many people, shedding rises at two points:
- Late summer (August, September): the first extra hairs appear on the brush and in the plughole.
- Autumn (September to November): this is the clearest peak. October is often the month when you notice the most hair on your pillow.
- Spring (March, April): a second, milder rise happens for some people.
Studies have observed this pattern. A Swiss study published in 2009 in the journal Dermatology (Kunz, Seifert and Trüeb), carried out on several hundred women followed over several years, found a higher proportion of resting hairs in summer, which points to more visible shedding a few months later, in autumn.
Why do we lose more hair in autumn?
Each hair follows a three-stage cycle: a long growth phase (several years), a short transition phase, then a resting phase of about three months, at the end of which it falls out to make way for a new hair. To understand this cycle better, read our article how much hair grows per month. In summer, a larger share of hairs seems to enter the resting phase at the same time. Three months later, they fall out together: this is autumn hair loss.
The exact reason is not settled. Researchers point to day length and sunlight, a leftover of moulting in other mammals. Summer sun, salt and chlorine do not make hair fall out at the root, but they do weaken it: some of the hair you find in September is actually broken hair. To tell them apart, see our article hair breakage or hair loss.
How long does seasonal shedding last?
Usually 4 to 8 weeks, sometimes a little longer. It stops on its own without leaving thin patches, because the hairs that fall are replaced by new hairs already growing. If shedding goes on beyond two or three months, or if density drops noticeably, it is probably no longer simple seasonal shedding.
Hair loss from stress: telogen effluvium
Significant stress can push a large number of hairs into the resting phase all at once. The result is diffuse shedding across the whole scalp, which doctors call telogen effluvium. It affects women and men alike and can be heavier than seasonal shedding.
Why shedding starts 2 to 3 months later
This delay is what confuses everyone. Hairs that entered the resting phase during the stressful period only fall out at the end of that phase, 2 to 3 months later. So you lose hair just as you start to feel better, and you do not link it to the difficult time in summer or spring.
The most common triggers
- Emotional shock: bereavement, a break-up, a very demanding period at work, exams.
- Physical stress: high fever, infection, surgery, an accident.
- Childbirth: postpartum hair loss follows the same mechanism.
- A strict diet or rapid weight loss.
- A deficiency, particularly iron, which is common in women.
Does the hair grow back?
Yes, in the vast majority of cases. Shedding usually settles within 3 to 6 months once the cause has passed, and hair grows back at its usual pace, about one centimetre a month. So it takes several months to see visible volume again. If the stress continues, shedding can last longer: one more reason to talk to a doctor.
Normal or worrying: how to tell the difference
The two types of shedding at a glance:
| Sign | Seasonal shedding | Stress shedding |
|---|---|---|
| When | Late summer and autumn, September to November | 2 to 3 months after the stressful event |
| Trigger | The natural rhythm of the hair cycle | Emotional shock, fever, surgery, crash diet |
| How long | Usually 4 to 8 weeks | Most often 3 to 6 months |
| What it looks like | Diffuse, with no bald patch | Diffuse, all over the head, sometimes heavier |
| Regrowth | On its own | Yes, once the cause has passed |
Seasonal or stress-related shedding is diffuse, temporary and does not leave bald patches. Some signs, however, mean you should see a doctor:
- Round patches with no hair: this is the sign of alopecia areata, an autoimmune condition that is different from stress shedding and needs a doctor.
- A widening parting or a receding hairline that develops gradually over months: this points more towards androgenetic alopecia. If you are under 35, our article hair loss in young women explains the possible causes.
- Itching, redness, thick dandruff or pain on the scalp.
- Shedding that lasts more than three months, or that comes with unusual tiredness, irregular periods or weight loss.
What helps during seasonal or stress shedding
- Patience: seasonal shedding stops on its own. Avoid trying lots of new products within a few weeks, as you will not know what works.
- A balanced diet: protein at every meal, foods rich in iron (lentils, meat, fish), zinc and omega-3. A supplement is only useful if you have a deficiency, ideally confirmed by a blood test.
- Sleep and stress management: go to bed at regular times, move every day, take breaks. It will not stop shedding already under way, but it lowers the risk of a new wave.
- Gentle habits: detangle from the ends up, avoid hairstyles that pull, turn down the hairdryer heat, choose a mild shampoo.
- Scalp care: a serum with cosmetic active ingredients can support density while hair grows back. Our roll-on hair growth serum by Orvova, a 25 ml bottle, combines rosemary (3%), Redensyl (3%), Aminexil (2%) and Anagain (2%), with no minoxidil or hormones, and a rollerball that massages the scalp. It does not treat alopecia and needs at least three months of regular use. To build it into a routine, follow our 5-step anti-hair-loss routine.
- Cover up in the meantime: if your parting or the top of your head looks thinner, a hair thickening powder dabbed at the roots tints the scalp to match your hair. It does not make hair grow, but it makes the area less visible while your hair comes back, and it washes out with shampoo.
When to see a doctor
See your GP or a dermatologist if shedding is sudden and heavy, lasts more than three months, if you notice patches, or if you have other symptoms. A blood test can often check iron (ferritin), thyroid function and vitamin D. If you are pregnant or breastfeeding, ask your doctor before using any anti-hair-loss product.
Sources
- Kunz M, Seifert B, Trüeb RM, Seasonality of hair shedding in healthy women complaining of hair loss, Dermatology, 2009
- American Academy of Dermatology, Do you have hair loss or hair shedding?, page accessed 2026
Frequently asked questions
Which month do you lose the most hair?
Most often in September, October and November, with a peak around October. A second, milder rise sometimes happens in spring.
How long does autumn hair loss last?
Usually 4 to 8 weeks. Beyond two or three months, it is best to look for another cause with a doctor.
Can stress cause hair loss?
Yes. Significant stress can trigger telogen effluvium, diffuse shedding that appears 2 to 3 months after the event.
Does hair lost to stress grow back?
In the vast majority of cases, yes. Shedding settles within a few months once the cause has passed, then hair grows back by about one centimetre a month.
Hair loss from stress: what should you do?
Tackle the cause where possible, eat a balanced diet, sleep well, treat your hair gently and see a doctor if shedding lasts more than three months.
