Here’s Why Your Hair Is Thinning (or Completely Falling Out), According to Doctors
This article was medically reviewed by Mona Gohara, M.D., a board-certified dermatologist and member of the Prevention Medical Review Board.
Everyone loses hair from time to time. It could happen during your morning shower, while you’re blowing it dry, or when you give it a quick brush—and that’s totally normal.
“On average, we lose 50 to 100 hairs a day,” says Francesca Fusco, M.D., a New York City-based board-certified dermatologist who specializes in hair loss. “That’s just hair going through its cycles, and there will be a new one to replace it.”
But when your hair starts falling out consistently in large amounts, you start noticing bald patches, or your hairline starts to recede in places it didn’t before, you may be dealing with something more serious.
Don’t assume you’re the only one going through this. “Hair loss is extremely common in women. In fact, it’s getting more and more common,” says Gary Goldenberg, M.D., assistant clinical professor of dermatology at the Icahn School of Medicine at Mount Sinai in New York City.
Beyond the physical aspect, it can take a toll on a person emotionally—especially for women, according to a 2015 review of research. Because hair is so closely identified with femininity, it can impact your self-esteem, make you feel depressed, and get in the way of your relationships with other people.
But to fight it, you need to know why your hair is falling out in the first place. Here, dermatologists and other specialists explain why you're losing more hair than usual—and the best treatments to restore its volume and shine.
1. Telogen effluvium
Telogen effluvium is a temporary condition that can occur after pregnancy, major surgery, drastic weight loss, an illness (yes, including COVID-19), or extreme stress, in which you shed large amounts of hair every day, usually when shampooing, styling, or brushing. During telogen effluvium, hair shifts faster than usual from its growing phase into the “resting” phase before moving quickly into the shedding (or telogen) phase. “High stress environments prevent the body from giving hair the TLC that it needs, causing hair to shed and fall out,” Dr. Goldenberg says.
✔️The symptoms: Women with telogen effluvium typically notice hair loss six weeks to three months after a stressful event. At its peak, you may lose handfuls of hair. “It can be very distressing,” Dr. Goldenberg says.
✔️The tests: There are no tests for telogen effluvium, but your doctor may ask you about recent life events and look for small “club-shaped” bulbs on the fallen hair’s roots. The bulbs mean the hair has gone through a complete cycle of growth, suggesting that the cycle may have sped up due to stress.
✔️The treatments: In some cases, such as after pregnancy or major surgery, you may have to bide your time until the hair loss slows. “It usually resolves. But, in some women, it can become more chronic,” says Dr. Goldenberg. Your best bet? Find a way to unwind to lower your stress levels (These science-backed ways to relieve stress are a good place to start.)
Taking a hair growth vitamin or supplement—such as biotin or other forms of vitamin B—may also be helpful, says Dr. Goldenberg. Just check in with your doctor first to make it won’t interfere with any other medications you may be taking.
2. Hereditary hair loss
Genetic hair loss or thinning is known as androgenetic alopecia and is the most common cause of hair loss, according to the American Academy of Dermatology (AAD). The gene can be inherited from either your mother’s or father’s side of the family, though you’re more likely to have it if both of your parents had hair loss.
✔️The symptoms: The condition develops slowly and may start as early as your 20s, and women with this trait tend to develop thinning at the hairline behind the bangs, says Pamela Jakubowicz, MD, a board-certified dermatologist at Montefiore Medical Center in New York City. Another red flag is a widening part, and the hair loss may be diffused, meaning it’s spread across the entire scalp.
✔️The tests: Your dermatologist will examine the pattern of hair loss to determine if it’s hereditary and order blood work to rule out other causes, Dr. Jakubowicz says. A biopsy of your scalp is sometimes done to see if the hair follicles have been replaced with miniaturized follicles, a surefire sign of hereditary hair loss.
✔️The treatments: While there’s no way to completely prevent hereditary hair loss, you can slow the thinning by applying minoxidil (aka Rogaine)—the only FDA-approved ingredient found to improve hair loss—to the scalp twice a day. It works by enhancing the size of the follicles, resulting in bigger strands of hair. (Just note that women should not use minoxidil if they are pregnant or nursing.)
Men may be treated with minoxidil or finasteride (Propecia), an oral medication. “I also recommend a multivitamin with biotin, zinc and copper,” Dr. Goldenberg says. He’s also seen success in his patients with a treatment called platelet rich plasma injections, a procedure in which your blood is drawn and then placed into a machine to separate the red blood cells from plasma. This plasma—which is “rich in platelets that contain growth factors,” per the AAD—is then injected into the hair follicles directly.
3. Alopecia areata
Alopecia areata is an autoimmune disorder in which the immune system attacks hair follicles. It may affect up to nearly 7 million people in the United States and occurs in all genders, ages, and ethnicities. The cause is unknown, but it may be triggered by stress or illness, Dr. Goldenberg says.
✔️The symptoms: The condition can occur in three forms. Alopecia areata commonly causes round, smooth patches of baldness on the scalp, eyebrows, or legs, Dr. Fusco says. Total hair loss on the head is known as alopecia totalis, while hair loss that occurs all over the body is called alopecia universalis. “Some patients have reported that before the bald spot occurred, they felt something in that area—a tingling or an irritation,” Dr. Fusco says.
✔️The tests: Observing the pattern of hair loss can usually determine if you have alopecia areata, as can blood tests. You may also be given a test to measure your hormones to rule out underlying conditions that may cause hair loss.
✔️The treatments: Alopecia areata is usually treated with intralesional corticosteroids, Dr. Fusco says. For more advanced cases, there are also promising clinical studies involving JAK inhibitors like oral tofacitinib (Xeljanz) that has resulted in regrowth for some. Minoxidil (Rogaine) may also help. It’s also important to reduce stress.
4. Traction alopecia
Traction alopecia is a form of hair loss that happens as the result of tight or heavy hairstyles, according to the AAD. It “forcefully pull hairs out of the scalp. This causes inflammation in the hair follicle that ultimately leads to scarring and destruction of the hair follicle,” says Oma N. Agbai, M.D., assistant clinical professor of dermatology at the University of California, Davis School of Medicine.
“It’s very commonly seen in people of African descent that wear tight hairstyles like braids, weaves, and even dreadlocks,” says board-certified dermatologist Ife J. Rodney, M.D., founding director of Eternal Dermatology + Aesthetics in Fulton, MD. “Braids and weaves put direction tension on the scalp and hair follicles. With dreadlocks, even if they’re not done tightly, the weight of them can create tension.”
However, Dr. Rodney says, anyone can experience traction alopecia. “I see a lot of military women that have to wear their hair in tight buns and have traction alopecia,” she says. “Ballet dancers can get it, too.”
✔️The symptoms: Early on, you might see scaling and flaking along the hairline, along with what appears to be small bumps around the hair follicle, Dr. Rodney says, which are the result of inflammation around the hairline. There can also be scalp tenderness. If caught early enough, the hair should grow back, Dr. Rodney says. But if it continues for years, “the hairs won’t grow back.”
✔️The tests: There is no set test for alopecia traction, but your doctor will examine you and may want to get a biopsy to help determine if you have the condition, Dr. Agbai says. “Traction alopecia can look very much like other types of hair loss such as frontal fibrosing alopecia or alopecia areata, and a biopsy can differentiate this from the other types of alopecia and guide treatment,” she says.
✔️The treatments: First, your doctor will urge you to change your hairstyle to something less tight. “Wear your hair down and around your face,” Dr. Rodney says. “If you have braids, you have to ask your hairstylist to make them loose. If you have dreadlocks, you’ll want to keep them on the shorter side so they’re not too heavy on the scalp.” She also recommends loosening your buns or ponytails if you pull your hair back that way.
Your doctor may also recommend using a steroid ointment to treat superficial inflammation around your hair follicles. “We can also do steroid injections—which are not too uncomfortable—to get the medication to the root of the bulb of the hair follicle,” Dr. Rodney says.
Overall, Dr. Rodney recommends being aware of how your scalp feels. “If your hairstyle feels tight or uncomfortable at all, it’s too tight,” she says. “There should be no discomfort at all.”
5. Medication side effects
Certain medications, like some cholesterol-lowering drugs, blood pressure drugs, warfarin (an anti-coagulant), psoriasis medications, anti-seizure medication, and anti-arrythmia drugs all have hair loss as a potential side effect, says women’s health expert Jennifer Wider, MD.
✔️The symptoms: You may find that you start to lose your hair three months or so after you begin a new medication.
✔️The tests: Talk to your doctor about specifics. The type of medication you’re taking will determine what they test for, although your doctor may also look into whether you have an underlying condition, just to be safe.
✔️The treatments: Your doctor may recommend switching to another medication, Dr. Wider says, or supplementing with something else to try to minimize the side effects.
6. Thyroid problems
Thyroid problems are common in women, especially over the age of 50, says Los Angeles-based endocrinologist Theodore C. Friedman, MD, MPH. In fact, 1 in 8 women will develop a thyroid disorder in her lifetime, according to the American Thyroid Association.
Your thyroid—the small, butterfly-shaped gland that sits at the base of your neck—is responsible for producing thyroid hormone, which is responsible for everything from your basal metabolic rate—the rate at which your body uses oxygen and energy to function—to the growth of your hair, skin, and nails.
But when you don’t have the right amount, you may notice changes in bodily functions. When too little is pumped out, you are said to have hypothyroidism, or an underactive thyroid. If your body makes too much of the hormone, you’re said to have hyperthyroidism, or an overactive thyroid.
✔️The symptoms: Hypothyroidism (too little hormone) may cause a host of symptoms, including unexplained weight gain, fatigue, constipation, depression, and difficulty concentrating. Hair, nails, and skin may become more brittle and break more easily. Hyperthyroidism (too much hormone) is less common than hypothyroidism, but may cause inexplicable weight loss, heart palpitations, nervousness, irritability, diarrhea, moist skin, and muscle weakness. Both much or too little thyroid hormone can affect your hair follicles freak out, resulting in hair loss.
✔️The tests: A blood test measures thyroid-stimulating hormone (TSH), which is produced by the pituitary gland in an attempt to coax the thyroid to make thyroid hormone. Excess TSH usually indicates hypothyroidism, while abnormally low levels suggest hyperthyroidism.
✔️The treatments: “Fixing thyroid imbalances is an important part of the treatment,” Dr. Goldenberg says. Thus, your doctor may prescribe a thyroid hormone medication to restore levels to normal. Regular TSH tests might be done to ensure an adequate dosage.
7. Iron deficiency anemia
An iron deficiency seems like an unusual reason for hair loss, but women can “absolutely” have hair loss while struggling with this, Dr. Goldberg says. Women who have heavy periods or don’t eat enough iron-rich foods may be prone to iron deficiency, in which your body doesn’t create enough hemoglobin, a protein that transports oxygen to the tissues in your body. In turn, your red blood cell count drops quickly, zapping your energy. About 10 million people in the United States are iron deficient, per one 2013 review of research, and it’s more common in women than men.
✔️The symptoms: Iron deficiency anemia causes extreme fatigue, weakness, and pale skin. You may have difficulty concentrating and also notice headaches, or cold hands and feet. Any type of exertion may leave you short of breath. Your hair may also start to thin and fall out, Dr. Goldenberg says.
✔️The tests: A blood test to measure ferritin, the protein that stores iron in your body, is usually needed to diagnose iron-deficiency anemia. Your doctor may also check your blood level of hematocrit, which gauges how much of your blood is made up of red blood cells.
✔️The treatments: Eat iron-rich foods such as beef, pork, fish, leafy greens, fortified cereals, and beans—preferably, along with foods rich in vitamin C, which enhances iron absorption. Women need at least 18 milligrams of iron a day and 8 milligrams after menopause. While supplementation may be necessary, you should talk to your doctor about recommended dosage before popping a pill.
8. Polycystic ovary syndrome
As many as five million women in the United States suffer from polycystic ovary syndrome (PCOS). The condition, which can begin as early as age 11, is caused by a hormonal imbalance in which the ovaries produce too many male hormones. PCOS often causes infertility.
✔️The symptoms: PCOS can cause facial hair growth, irregular periods, acne, and cysts on the ovaries. And while you may experience hair loss on your scalp, you may notice more hair elsewhere on the body, Dr. Fusco says.
✔️The tests: Your doctor is likely to do a blood test to look for elevated levels of testosterone and DHEAS (dehydroepiandrosterone), a by-product of testosterone.
✔️The treatments: Most cases of PCOS are treated with birth control pills such as Yasmin, which contains a potent anti-androgen that blocks testosterone. If you can’t use birth control pills, your doctor may prescribe spironolactone (Aldactone), which also blocks male hormones. Losing weight can also help by decreasing the effect of the male hormones.
You may need to be patient while your your hair comes back. “When hormonal conditions like PCOS are treated, it may take several weeks to months for associated hair loss may improve,” says Joshua Zeichner, MD, director of cosmetic and clinical research in dermatology at Mount Sinai Hospital in New York City.
9. Psoriasis, dandruff, and other skin conditions of the scalp
An unhealthy scalp can cause inflammation, and “if the inflammation is deep in the scalp, it can cause hair loss,” Dr. Goldenberg says. Skin conditions that lead to hair loss include seborrheic dermatitis (dandruff), psoriasis, and fungal infections such as ringworm.
✔️The symptoms: Seborrheic dermatitis causes the scalp to shed its skin, so you’ll notice greasy, yellowish scales on your shoulders or in your hair. It may be the result of yeast called Malassezia, hormonal changes, or excess oil in the skin. Scalp psoriasis, an autoimmune condition that causes excessive skin cell turnover, produces a very thick white scale that can bleed if pulled off.
With ringworm, a fungus you contract by touching an infected person or animal, you’ll notice red patches on your scalp, which may be diffused, Dr. Jakubowicz says.
✔️The tests: A physical exam of the scalp will help determine which condition you have. A fungal culture and possibly a biopsy of the scalp may pinpoint ringworm. Just don’t wait on this. “If you already have inflammation, itching, hair breakage or hair loss, see your dermatologist to make sure it’s not a more serious skin condition,” Dr. Goldenberg says.
✔️The treatments: Each condition usually requires a prescription: a medicated shampoo for dandruff, medications or light therapy for psoriasis, and oral antifungals for ringworm.
10. Excessive styling
Too much shampooing, styling, and dying can harm your hair, leading to hair breakage and loss, Dr. Goldenberg says. Often, it’s a combination of treatments—keratin, coloring, and blow-drying, for instance—that does the damage.
✔️The symptoms: If the fallout is occurring from external damage caused by styling, it will simply break, and you won’t see those club-shaped telogen bulbs at the ends.
✔️The tests: Dr. Jakubowicz does a pull test: She takes a small handful of about 50 strands, pulls gently, and checks to see whether the hair that comes out has bulbs on the ends.
✔️The treatments: Avoid using appliances that overheat your hair. Set your hair dryer on cool and low settings and minimize your use of flat and curling irons (say, for special occasions). If you use hair gel or hair spray, don’t wait for it to dry before you comb through it, because the hair will harden and be more likely to break.
If you must dye your hair, consider pivoting just one or two shades from its normal color: The more severe the color change, the more chemicals you require—resulting in excess breakage.
11. A low-protein diet
While it’s rare for people living in developed countries to have a protein deficiency, if you’ve recently become a vegan or vegetarian and haven’t worked enough plant-based proteins into your diet, it’s possible you may not be getting enough of the nutrient.
When this happens your body may ration whatever protein is already in your body by shutting down hair growth, according to the AAD. This typically occurs two to three months after your protein intake dips.
✔️The symptoms: In addition to hair loss, a protein deficiency may cause bloating, brittle nails, fatigue, and weakness. When your hair breaks, you won’t see those club-shaped telogen bulbs at the ends.
✔️The tests: If your doctor is worried a lack of protein may be to blame for your thinning hair, he or she may do a blood draw for a total protein test, which measures of all of the proteins in your blood.
✔️The treatments: Eating more protein will likely stop the hair loss, Dr. Goldenberg says, since a lack of protein is a form of malnutrition, which stresses the body. Meat, eggs, and fish are excellent sources of protein, as are many plant-based foods, including tofu, legumes, nuts, and tempeh.
12. Menopause
Menopause is a normal condition that affects women as they age. By definition, menopause is a point in time 12 months after a woman’s last period, per the National Institute on Aging (NIA). During this time, your body produces less estrogen and progesterone hormones.
✔️The symptoms: Everyone experiences menopause differently, but you may notice symptoms like hot flashes, trouble sleeping, moodiness, irritability, pain during sex, and depression, the NIA says. Hair loss can also be an issue. “During menopause, hair loss occurs because of the changes in hormones,” says Dr. Wider. “When estrogen and progesterone drop, the result is a slow down of hair growth and a thinning of hair in many women.”
✔️The tests: Your doctor may suggest a blood test to check your follicle-stimulating hormone and estradiol levels to rule out any other causes for the changes you’re going through, the NIA says.
✔️The treatments: “It’s important to treat your hair well and gently during this time,” Dr. Wider says. “Avoid extreme heat with hair dryers and ironing tools. Use mild shampoos and conditioners without added chemicals. Keep your body hydrated.” If that doesn’t help, talk to your doctor about medication options.
13. Dramatic weight loss
“Studies have shown that rapid or significant weight loss can trigger hair loss,” Dr. Wider explains, commonly due to the deprivation of certain nutrients, including protein.
✔️The symptoms: You’ll notice if you start to lose weight quickly (typically defined as losing more than 5 percent of your weight in six months to a year). Your pants will be looser and, if you weigh yourself regularly, you’ll see the number on the scale go down. If you’re experiencing hair loss, it can come on suddenly.
✔️The tests: If you’re not trying to lose weight, your doctor may recommend blood tests to see what’s behind your rapid weight loss—which may include things like simply not eating enough, thyroid issues, celiac disease, or even mental health disorders like depression.
✔️The treatments: If you’re trying to lose weight, talk to your doctor about any vitamin deficiencies that could be behind your hair loss. If not, and there is an underlying condition behind your weight loss, know this: “Once a person regains the weight, the hair loss will stop and begin to grow back” after the appropriate treatment is determined, Dr. Wider says
14. Lupus
Lupus is a chronic autoimmune disease in which the body’s immune system attacks its healthy tissues. The condition affects about 1.5 million Americans, according to the Lupus Foundation of America, and tends to strike women during their childbearing years.
✔️The symptoms: Lupus often causes extreme fatigue, headaches, oral ulcers, and painful, swollen joints. Many people develop a butterfly-shaped rash across the bridge of the nose and become more sensitive to the sun. Other symptoms include fever, swelling in the feet and hands and around the eyes, chest pain, and anemia.
Many people with lupus also experience hair loss, which may be mild and occur while shampooing or brushing your hair—or it may be more severe, coming out in patches and accompanied by a rash on the scalp, says Arthur Weinstein, MD, director of the division of rheumatology at the Washington Hospital Center. Because these symptoms occur in many other conditions, lupus is often called the great imitator.
✔️The tests: A rheumatologist will examine joints and other tissues for signs of inflammation, such as heat, pain, swelling, and redness. A blood test to measure levels of anti-nuclear antibodies (ANA) may also indicate lupus. Rheumatologists will also determine if patients have four of 11 diagnostic criteria set by the American College of Rheumatology, though fewer criteria along with a skin biopsy may sometimes indicate lupus, Dr. Weinstein says.
✔️The treatments: See a rheumatologist if your hair loss is accompanied by joint pain, fatigue, or other symptoms of lupus. If you also have a rash on the scalp, you need to see a dermatologist, who is likely to prescribe a topical cream.
15. Chemotherapy
Chemotherapy works to kill cancer cells in your body, but it can also kill off healthy cells in the process, including ones behind hair growth. “Chemotherapeutic agents target rapidly growing cells (like cancer) in order to stop the growth,” Dr. Wider says. “Unfortunately, they also target healthy cells like hair cells and, as a result, a person in chemotherapy can lose their hair.”
✔️The symptoms: You’ll may notice thinning hair and/or hair that falls out in clumps.
✔️The tests: You probably won’t need any, given that hair loss is a common side effect of chemotherapy.
✔️The treatments: There is a fairly new FDA-approved treatment called a cooling cap that can help. Scalp cooling is thought to prevent hair loss by reducing blood flow to hair follicles, per the National Cancer Institute. When the scalp is cooled, blood vessels constrict, and that can limit the amount of chemotherapy drug that reaches hair follicles.
16. Trichotillomania
Trichotillomania is a condition that causes an overwhelming urge to repeatedly pull out your own hair, according to the National Organization for Rare Disorders (NORD), causing hair loss. While this can impact hair all over your body (including eyebrows and eyelashes), hair on the scalp is most commonly affected.
✔️The symptoms: Symptoms generally include constant hair-pulling and an urge to pull your hair. People with the condition also may feel tension before they pull and a release afterward, NORD says. Because the scalp is a main point of pulling, people with trichotillomania may focus on one or two areas, resulting in bald patches. The condition can be very distressing.
✔️The tests: People are usually diagnosed with trichotillomania after a doctor does a clinical evaluation, takes a detailed patient history, and rules out other potential causes of hair loss.
✔️The treatments: Trichotillomania is usually treated with psychotherapy and medication, NORD says. Psychotherapy usually includes cognitive behavior therapy, which tries to identify and alter the thoughts and emotions that causes a person to pull their hair. Several medications, including clomipramine, n-acetyl cysteine, and olanzapine may also help.
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