8 Causes that May Be At the Root of Your Hair Loss

Wondering how much hair loss is normal? Find out what’s causing this distressing hair issue—and what you can do about it.  

Whether you’ve spent your life trying to style thick, unruly strands into submission or add volume to limp locks, you’ve probably thought of your hair as “problem hair” at some point. But if you’ve been noticing more hair in your shower drain lately or your hair is starting to thin, that term has taken on new meaning—and new concern. What’s causing this sudden bout of hair loss? And, more importantly, can you stop it?

The first thing you should know is that you’re not alone. Experts estimate that more than 50 percent of women will experience hair loss at some point in their lives, with around 30 million women (or about a third of that number) suffering from female pattern hair loss. But that’s just one potential cause of your hair woes—and you need to figure out what’s actually going on to effectively treat and ideally reverse this problem.

So, how much hair loss is normal?

Let’s get right to it: According to the American Academy of Dermatology (AAD), it is normal to shed anywhere from 50 to 100 strands of hair per day. The Cleveland Clinic adds that this number may go up slightly if you wash your hair only once or twice a week, especially if you have long hair, due to a buildup of hair that’s on its way out. This is all part of your hair’s normal life cycle: anagen (active growth), catagen (transition), and telogen (resting and shedding). This cycle takes anywhere from two to six years, and you usually don’t notice it since your follicles are all at various stages of growing and shedding.

Things are decidedly not normal, however, “if you are experiencing hair shedding of greater than 125 strands a day or if you have observed bald spots on your scalp or a widening of your hairline,” says Michele Green, MD, a dermatologist at Lenox Hill Hospital in New York City. That’s when it’s time to take a closer look at your hair health.

Hair loss vs. hair shedding: What’s the difference?

Hair Shedding

The AAD states that hair loss occurs when something stops the hair from growing. True hair loss (aka anagen effluvium), when not resulting from an outside factor like chemotherapy or harsh hairstyling chemicals, is often the result of genetics, says trichologist Penny James, owner of the Penny James Salon in New York City. James notes that with female pattern baldness, or androgenic alopecia, women will notice thinning near the temples and the crown area—something you may have noticed in your female relatives. If, however, you’re noticing small round patches without hair on your scalp, that’s likely the result of an autoimmune disorder (alopecia areata) that attacks hair follicles. While subsequent hair loss can be halted and there are treatments that can help, whether or not the condition is reversible depends on its cause.

On the other hand, excessive hair shedding (telogen effluvium) occurs “when the hair growth cycle has been interrupted and the hair has been pushed prematurely into the telogen stage—the falling-out stage,” James explains. This can be caused by a variety of factors including diet, stress, hormonal changes, and styling. James notes that the shedding will usually be all over the head, as opposed to localized patches, but it may be more noticeable in already-thinner areas. The good news is that in most cases, once you address the underlying issues, you won’t necessarily have lasting problems.

The causes of hair loss

So, what’s at the root of your problems? It’s essential to figure that out so you can proceed with the correct course of treatment, whether it’s a relatively simple fix you can handle yourself or something that will require more aggressive intervention. Of course, it’s always a good idea to consult a professional, who can make sure you’re on the right track and evaluate your overall health, but the following common causes can help you narrow things down. 


Yep, the same hormonal changes that can cause hot flashes, night sweats, weight gain, and other delightful issues can also lead to hair loss. “During menopause, levels of estrogen are decreased,” explains Dr. Green. “The decrease in estrogen can lead to heightened androgen sensitivity and, in turn, cause weakening and shrinkage of the hair follicles.” Treatments for menopause-related hair loss can range from oral medication and hormone replacement therapy to topical Minoxidil treatments and platelet-rich plasma (PRP). (More on PRP therapy below.)


Not to stress you out further, but stress itself may actually be causing your hair to fall out. “Stress is a huge problem with hair loss,” says James. “I would say 90 percent of my clients are suffering from acute stress these days.” She explains that when you are stressed, the hormone cortisol wreaks havoc on your body, potentially affecting your thyroid and adrenal glands, aggravating your scalp, and even causing eczema, psoriasis, seborrheic dermatitis. 

At the most basic level, that hormone surge, says Dr. Green, can disrupt the hair growth cycle, causing hair to go into a longer period of rest and stop growing. It can take six weeks to six months after a stressful event for hair loss to occur. While most people’s hair will rebound on its own once this cycle of stress and loss has passed, Dr. Green notes that certain types of stress-related hair loss can be permanent if not treated early. 


Your fever may have broken long ago and that illness may now be a distant memory for you…but your body still remembers. Any major health event, especially one that comes with a high fever, can push more hair than usual into the shedding phase, but you won’t experience this shedding until a few months later. While this side effect may last for six to nine months, the good news is that it should eventually stop on its own. 

In case you were wondering, yes, this has been yet another unexpected side effect of COVID-19. Aside from the plethora of anecdotal evidence, one study from China published in The Lancet found that 22 percent of those hospitalized with COVID were still reporting hair loss six months after they were discharged. While this can happen with any major illness, COVID can hit you with a double dose of physical and emotional stress.

Nutrient deficiencies

As they say, you are what you eat—and if you’re not getting the proper nutrients, your hair will reflect those deficiencies. “Poor nutrition can cause malabsorption and inflammation in the body, which can disrupt the growth cycle of the hair,” says Dr. Green. “Inflammation does not allow the cells to repair completely, and that cell damage results in hair loss.” A nutrient-dense diet, on the other hand, can aid in proper absorption, cellular turnover, and hormonal balance and lead to longer, stronger, healthier hair. 

First, make sure you’re getting a proper amount of amino acids and proteins. If you’re low on protein, James says, you might be anemic, which can drive down your iron and cause hair shedding. Beyond that, she says to look into vitamins A, C, D, and E, as well as B complex and zinc, which are important for healthy follicles and hair growth. If your diet has certain restrictions or you’re trying to lose weight, you should pay special attention to this. (Side note: Significant weight loss—think 20-plus pounds—can also be a shock to your system and cause hair loss.)

Hormonal issues

A decrease in estrogen during menopause isn’t the only hormonal issue that can affect your hair. Both hypothyroidism and hyperthyroidism can result in hair loss, and if either is autoimmune-related, it can result in the previously discussed alopecia areata. Polycystic ovary syndrome (PCOS) can also be the culprit. Higher-than-normal levels of male hormones, or androgens, in women with PCOS can “cause the hair follicles to thin out and shrink over time, leading to female pattern baldness,” says Dr. Green. In both cases, getting your hormones on track (albeit in different ways) can help with all of your symptoms, including hair loss.


Your hair will never look as luxurious as when you’re pregnant…or as lackluster as in the weeks after giving birth. This excessive shedding results from falling estrogen levels, according to the AAD, and generally peaks about four months after giving birth. While it can be disconcerting to see more hair in your brush or thin patches on your scalp, your hair should return to normal within 12 months. Still, make sure you’re getting proper nutrients and keep an eye on your stress levels so that this pregnancy-specific issue doesn’t spiral into another one.

“Pulling” hairstyles 

Sometimes, the things we do to make our hair look amazing can completely backfire. That’s the case with certain hairstyles, including tight buns and ponytails, as well as tight braids, hair extensions, and weaves. The pulling inherent in these styles can cause a type of hair loss known as traction alopecia—which, if not dealt with, can result in permanent hair loss. If you notice broken hairs around your hairline, a receding hairline, or patchy loss, it might be time to loosen up your hairstyle for a while and allow hair to heal and recover.


Similarly, repeated harsh chemical treatments—from relaxers to perms—can be problematic and, in extreme cases, cause scarring of the scalp, which would impede hair growth. On the other hand, over-styling with hot tools (especially if they’re not used correctly), dyeing hair too frequently, and aggressive brushing can make strands brittle and cause them to break more easily. While these latter issues do not result in true hair loss, your broken strands can exacerbate thinning and cause hair to look less than fabulous. 

What can you do to prevent hair loss and improve hair growth?

Hair loss in men

As mentioned earlier, your path forward really depends on what’s causing your hair loss or shedding. Hormonal issues, for example, may require medication to treat the larger issue; hair loss is simply a side effect. The same goes for hereditary hair loss that may be halted and helped with oral or topical medication or something like PRP (platelet-rich plasma). With this treatment, explains Dr. Green, a doctor injects concentrated blood plasma (created with your own blood but containing up to five times more platelets than it normally does) into your scalp. This can improve cell reproduction and blood vessel formation while also healing and stimulating hair follicles. 

While a professional can help you determine the best course of action, you can also do your part at home to stem the tide of shedding hair. Here are a few things everyone can try:

  • Keep stress in check. “The first step is to know you are stressed,” says James. “Then take action: Meditate. Take a walk outside. Turn off the phone. If you need to, seek professional guidance.” 
  • Make sure you’re getting the right vitamins and minerals. In addition to incorporating more of the good stuff in your meals, supplements can also work wonders. Zinc and biotin (one of the B complex vitamins) are two dermatologist and trichologist favorites since they help with follicle health and hair growth and strength, respectively. HUM’s Hair Sweet Hair contains both of these, as well as folic acid, fo-ti, B12, and PABA. (Bonus: These yummy gummies are also vegan.) 
  • Be kind to hair when styling it. “Our hair is a fiber made of protein and can only take so much heat before it burns and breaks off,” says James. “The key is to take organized sections when using a heated tool and not have the heat setting on too high.” If hair is fragile, she also recommends staying away from brushes with metal centers and plastic bristles and using wooden brushes with boar bristles instead.
  • Keep hair hydrated. Your choice of product will depend on your specific type of hair, but making sure that hair isn’t overly dry is key to maintaining cuticle health, says James. While B vitamins are a boon when consumed, there are no scientific studies that prove biotin is as effective when applied topically. That said, hair experts swear by certain biotin-infused shampoos and conditioners for keeping hair nourished and follicles healthy. 

Now take a deep breath. If you are experiencing any form of hair loss, it can feel devastating, but you have options. Finding a targeted treatment that’s right for you can change everything—and lead to the healthiest, fullest, most gorgeous hair you’ve ever had.

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