Why Do I Lose More Hair In Winter? Seasonal Hair Loss Is Totally A Thing, And Here's What Causes It

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Nothing ruins a nice, hot shower like a clump of hair slithering down your leg as you rinse out your shampoo. Twenty minutes later, you're six pages deep into a Web MD spiral as you research the causes of unexpected hair loss. As it turns out, though, seasonal hair loss is actually normal in the summer and late fall. It might be a bit unsettling to look at your brush and see enough hair for a year's supply of Donald Trump's toupees, but some extra shedding in the months leading up to winter is no cause for panic. So rejoice! Barring some other medical condition, you probably aren't balding after all.

According to Dr. Angela Phipps, D.O., A.B.H.R.S., and Medical Advisor to Hair Club, hair shedding is totally normal. "One may lose anywhere from 50 to 100 strands of hair per day. New strands of hair, which have an average life cycle of two to six years, replace those that we lose daily. Each hair follicle produces a new hair, which then grows in successive cycles before falling out," she tells Bustle.

The life cycle of a hair is divided into three phases: anagen, catagen and telogen. Here's what happens at each stage, according to Phipps.

  • Anagen Phase: Your hair grows around half an inch a month, and faster in the summer than in winter. The growth phase, or anagen phase, lasts an average of two to six years.
  • Catagen Phase: At the end of the anagen phase, your hair enters the catagen phase. A short transitional phase that lasts approximately 10 days.
  • Telogen Phase: Lastly, your hair enters the telogen phase, a resting phase when your hair shaft is released and falls out. The follicle then remains inactive for three months and the whole process is repeated. Each hair follicle is independent and goes through the growth cycle at different times, otherwise all your hair would fall out at once. Instead, you only shed a certain number of hairs per day, anywhere from 50 to 100 strands.
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Researchers have suspected for a few decades that people shed more at certain times of the year, and several small studies have suggested that hair grows thicker in the spring and starts to thin in the fall. It was only recently that researchers set out to see if these findings apply to everyone. In a study from Johns Hopkins and Washington University, scientists looked at Google Trends data from eight different English-speaking countries across the world between 2004 and 2016, focusing on terms related to "hair loss." Clearly, as much as scientists warn us against using the Internet to diagnose ourselves (because that way lies madness and cancer scares), they also know everyone does it anyway.

Comparing search data from month to month and season to season, they found that searches for hair loss followed a cycle. People searched for "hair loss" the most often in summer, followed by fall. It was the least common in the spring, suggesting that people's hair was thickest in March, April, and May.

By the end of summer and beginning of fall, though, telogen hair loss — the phase of when your hair stops growing and falls out — is in full swing. Interestingly enough, temperature was associated with hair loss searches, but it only appeared to have a small influence.

While more research is needed to explain why people lose hair in the summer, but the authors of the study have some ideas. One of the co-authors pointed out to TIME Health that in terms of evolution, hair (and fur) provides warmth, which is "less necessary during the summer months." Therefore, it's possible that humans evolved to grow more hair throughout the winter, when it can act as a blanket against the miserable cold, and shed it in the summer, when you don't need it in the sweltering heat.

Phipps agrees. "Some research suggests that women may experience slightly higher rates of telogen during the summer month of July, [where] one then sees the affected hairs falling out around three to four months later in mid-October or November. Exactly why this happens is unclear, but some suggest that stress brought on by the summer heat may have a factor," she explains.

This has been seen in other animals, too, so humans are in good company. "What is also interesting is that seasonal variations in hair loss also occurs in animals and has been noted in studies with rhesus monkeys, cats, and dogs. In particular, seasonal flank alopecia has been described in dogs," Dr. Shawn Kwatra told Medical News Today.

As far as human hair loss goes, though, hair shedding is pretty normal. According to the American Academy of Dermatologists, most people lose between 50 and 100 hairs each day, and stressors like giving birth, losing large amounts of weight, undergoing surgery, and so on can accelerate the amount you shed. Once that stress goes away, the hair tends to return to normal.

Baldness is often considered the realm of middle-aged men or people with alopecia, but most women can expect to experience some sort of hair loss as they age. One dermatologist told Allure that 50 percent of women will begin losing hair by the time they're 50 years old.

That being said, spotting some extra strands in your hairbrush doesn't mean you're balding at this very minute, especially if it's during the summer or fall. However, if you're interested in learning how to prevent seasonal hair loss, Phipps has some tips for you.

  • Wear a hat: "Cover your hair to shield it from snow, wind and rain. The elements dry your hair out and make it more prone to breakage," she shares.
  • Buy a humidifier: A surprising way to fight dry hair in the winter? Use a humidifier, suggests Phipps. "Indoor heating causes the air in your home to become very dry, pulling moisture out of your hair. Humidifiers help rehydrate the air and your hair to keep your locks looking lustrous," she says.
  • Get regular trims: Phipps also suggests getting regular hair trims every four to eight weeks to maintain hair health and keep your locks looking fresh. "Take a half inch off the bottom to reduce the chances of developing dry, split ends," she adds.
  • Lower the water temperature when you shower: "Even though a steamy shower might be just what you’re after when the temperature is below freezing, hot water can zap moisture from your hair making it brittle and more vulnerable to breaking," Phipps tells Bustle. Use warm water to lather up your shampoo and cool water to rinse.
  • Let hair air dry: "Allowing your hair to air dry is best. Blow drying draws moisture out of your hair increasing the chance of breakage," says Phipps. If you don't have enough time in the morning, consider taking a shower at night and let your hair dry while you sleep.
  • Don’t leave the house with wet hair: "Wet hair is more vulnerable to damage than dry hair. Walking outside in winter with a wet head can cause hair to freeze and break," Phipps explains. While air drying is best, it’s better to blow dry your hair than go outdoors with a saturated mane, she adds.
  • Use an oil treatment: "When winter wreaks havoc on your hair, restore moisture with an oil treatment," says Phipps. Her ingredient of choice? Argan oil.
  • Deep condition once a week: "Moisturizing is the name of the game for winter hair care. Use a deep conditioner weekly to replenish moisture and combat the effects of hot styling tools, indoor heating, and cold winter winds," she tells Bustle.

This post was originally published on Nov 1, 2017. It was updated and republished on June 25, 2019. Additional reporting by Sara Tan.

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