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Seasonal Hair Loss: Is It Common?

Katelyn Hagerty

Reviewed by Katelyn Hagerty, FNP

Written by Geoffrey Whittaker

Published 03/23/2023

Is seasonal hair shedding a thing, and if so, is excessive hair loss normal at certain times of the year? Here’s what you should know.

You probably notice it happening to your furry friend when the seasons change. Between the extra hair tufts all over your clothes and the wisps of their winter coat floating into the air every time you give them a good scratching, you know what seasonal hair shedding looks like already.

Can it happen to people, though?

We don’t typically think of humans as having summer and winter coats, mostly because the majority of us aren’t covered head to toe in a thick coat of fur. Even during those no-shave months, the dudes who describe themselves as “hirsute” don’t have the same impenetrable coat as your average golden retriever.

And yet, according to the very limited science on the topic, humans do indeed have seasonal changes in hair growth and the thickness of their hair.

Seasonal hair growth and loss aren’t crystal-clear concepts in the world of dermatology. Let’s take a look at what we know.

To understand seasonal hair shedding, you need to first understand the phases of hair growth — specifically the telogen phase of the growth cycle.

The telogen phase is generally considered the resting stage of the hair growth cycle. Depending on which experts you ask, there are either three or four phases: anagen, catagen, telogen and exogen.

The hair essentially begins growing and matures in the anagen and catagen growth phases, then comes to rest (and stops growing) in the telogen phase. During this time, it disconnects its root from the follicle and prepares to detach in the exogen phase before starting the process over again.

The anagen phase is years long, while the other combined phases typically only last a few months.

Every single strand of hair is in a slightly different part of this cycle of growth at any given time, which is good because it prevents you from going entirely bald once every few years.

But disorders like telogen effluvium can also suddenly shift larger numbers of follicles into the resting and shedding phase. And as it turns out, so can the changing of seasons.

You might assume that, like your furry friends, your own hair shedding has a seasonal component: less hair in the warm months and more hair in the cold months. 

To a certain extent, that’s correct.

Seasonal hair loss is a difficult idea to pin down, though several studies have tried. For instance, one 2009 study looked at hair loss in more than 800 otherwise healthy women and found that:

  • Hair growth and loss patterns have seasonal behaviors

  • There are more hairs in the telogen or resting phase of the growth cycle during the summer

  • Spring also sees a higher number of resting hair follicles

  • The fewest follicles are in the telogen phase during the winter

One explanation has to do with the number of daylight hours per season. Some experts believe low-daylight seasons reduce the actual shedding of hairs in the telogen phase and that a return to more daylight hours speeds up the shedding of club hairs.

However, this wouldn’t suggest that your hair cycles are speeding up or that hairs are going into the telogen phase with more frequency — just that more hairs in the telogen phase are disconnecting (something we all need to do more of in the summer). 

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Collectively, the data suggest summer is when you’re most likely to be shedding or losing additional hair. But just how common is this experience?

How common seasonal hair loss depends on your criteria. For instance, experts believe a version of seasonal telogen effluvium is the explanation for how most mammals shed their winter coats — which would make it pretty common, as pet owners know.

Researchers are slightly less clear on whether the impact is similar on humans, but they believe it “probably” plays a role.

Of course, that assumes a person’s seasonal hair loss is related to normal shedding cycles. Excessive shedding and long-term hair loss are different.

Some types of seasonal shedding are related to hair disorders that should also be considered, according to some research.

For example, in alopecia areata for instance (a type of hair loss disorder caused by an autoimmune reaction against your hair follicles), shedding patterns are actually reversed.

A 2018 study found that flare-ups of alopecia areata in over 300 children most often coincided with colder months like October, November and January, while the lowest months of incidence were May and August.

The researchers pointed to many unanswered questions about what triggers flare-ups. And since their research was retrospective, follow-ups would be needed to see if there was a causal relationship between season and shedding — or if it was simply a coincidence.

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Here’s the thing about telogen effluvium: it typically resolves itself after a period of months. When caused by bodily traumas like surgery, chronic stress or weight loss, for instance, telogen effluvium typically sets in between two to three months after the event and lasts roughly six months before things begin to normalize on their own.

If you want to be an active participant in solving the problem, consider medications like minoxidil, which may help in the resolution and recovery from telogen effluvium.

Conditions like alopecia areata, however, may require more lengthy or serious treatments. This is a good time to remind you that things like vitamins (which you can get from Hims) and other treatments for hair loss may help you in any number of circumstances, but that the effectiveness of a treatment is largely dependent on guidance from a healthcare professional.

Want the right treatment for your condition? You need to talk to a healthcare provider and get a proper diagnosis before starting your healthy hair journey.

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Seasonal hair loss is something that may resolve itself seasonally. If you lose hair in the summer, it may very well just be due to natural seasonal changes rather than a significant problem or disorder.

Though seasonal shedding may be nothing to worry about, it’s still best to talk to a healthcare professional if you have concerns. After all, letting time pass is the worst thing you can do if you’re fighting androgenic alopecia (also known as male pattern baldness).

If you’re seeing signs of hair thinning, we highly suggest a better-safe-than-sorry approach to treatment. With conditions like alopecia areata, androgenic alopecia and other types of potentially permanent hair loss, being proactive can mean the difference between saving the hair you have and losing more in the meantime.

To take the first step toward healthy hair and improved hair density, explore hair loss treatments at Hims today.

6 Sources

  1. Malkud S. (2015). Telogen Effluvium: A Review. Journal of clinical and diagnostic research : JCDR, 9(9), WE01–WE3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4606321/.
  2. Putterman, E., & Castelo-Soccio, L. (2018). Seasonal patterns in alopecia areata, totalis, and universalis. Journal of the American Academy of Dermatology, 79(5), 974–975. https://www.jaad.org/article/S0190-9622(18)32152-2/fulltext.
  3. Geyfman, M., Plikus, M. V., Treffeisen, E., Andersen, B., & Paus, R. (2015). Resting no more: re-defining telogen, the maintenance stage of the hair growth cycle. Biological reviews of the Cambridge Philosophical Society, 90(4), 1179–1196. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4437968/.
  4. Kunz, M., Seifert, B., & Trüeb, R. M. (2009). Seasonality of hair shedding in healthy women complaining of hair loss. Dermatology (Basel, Switzerland), 219(2), 105–110. https://pubmed.ncbi.nlm.nih.gov/19407435/.
  5. Almohanna HM, Ahmed AA, Tsatalis JP, Tosti A. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatol Ther (Heidelb). 2019;9(1):51-70. doi:10.1007/s13555-018-0278-6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6380979/
  6. American Academy of Dermatology Association. Hair Loss Types: Alopecia Areata Diagnosis and Treatment. https://www.aad.org/public/diseases/hair-loss/types/alopecia/treatment
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