If you notice lots of hair coming out in the shower or hairbrush, you’re probably wondering why your hair is falling out. There are many possible causes of hair loss, and it’s important to determine the one that’s affecting you so that you can treat the right problem.
Hair loss, or alopecia, is when your hair starts to thin, gradually shed, or fall out in clumps. Sudden hair loss can be temporary due to stressors, hormonal changes, medications, and other environmental factors. However, hair loss can also be permanent depending on the cause and how it affects the hair growth cycle. Learn more about why your hair is falling out, including causes, treatments, and when to contact a medical provider.
Typical hair growth always involves shedding old hair as you grow new hair in three cycles:
Anagen (growth phase): Hair grows in the follicle and pushes through your scalp. Catagen (transitional phase): The hair follicle starts to shrink, and hair growth slows down. Hair then separates from the follicle. Telogen (resting stage): The hair follicle becomes dormant and stops growing hair, causing you to shed hair.
People with normal hair growth usually lose 50 to 100 hairs a day. However, something isn’t quite right if your hair is thinning or falling out in clumps. Here’s how health conditions, stress, and hormonal changes can make your hair fall out—plus what you can do to regrow your hair.
Hereditary hair loss, or androgenetic alopecia, is hair loss caused by genetics or hormonal imbalances that affect androgen hormones (typically testosterone). Anyone can experience hereditary hair loss, but it typically affects males and is more commonly called male pattern baldness.
In males, hair starts thinning near the top of the head and forms a receding hairline (creating an “M” shape). Eventually, you can go completely bald. In females, the hair becomes thin all over without a receding hairline.
Treatment
There is no cure for hereditary hair loss, but treatment may help slow down hair loss or regrow hair. Hereditary hair loss treatments include:
Rogaine (minoxidil): An FDA-approved topical drug applied to the scalp to treat hereditary hair loss by helping to widen blood vessels to help improve hair follicle health and promote the growth cycle.
Propecia (finasteride): A 5 alpha-reductase type 2 inhibitor that prevents testosterone from turning into dihydrotestosterone (DHT), a hormone that can promote hair loss. This medication is taken orally and is FDA-approved to treat hereditary hair loss.
Red light therapy: This treatment uses a laser to trigger hair growth at the follicle to help treat male and female pattern baldness.
Spironolactone: A medication that helps block DHT and keep testosterone from affecting the androgen receptors that can lead to hair loss. This oral medication is usually used to treat female pattern baldness.
Hair transplant: This surgery involves implanting healthy hair follicles into areas of thinning hair. The transplanted hair is often taken from the sides or back of the head.
Hair naturally starts to thin, and growth begins to slow as you age. Age-related hair loss differs from hair loss caused by an increase in androgens because hormones do not influence it. Instead, aging causes your hair follicles to stop growing hair eventually. Going gray also changes the structure of your hair as it loses pigment that gives you hair color. The result is graying hair that eventually turns into fine, white hair.
Age-related hair loss is inevitable, but if you catch hair loss as it starts, treatments like minoxidil can help regrow hair.
Alopecia areata is a condition that causes the immune system to attack healthy hair follicles, leading hair to fall out. Types of alopecia areata include:
Patchy alopecia areata: The most common type where people lose small patches of hair on the scalp or body. Hair may grow back on its own, while others may need treatment. Alopecia totalis: Complete or near-complete hair loss on the scalp.Alopecia universalis: A rare type where people lose all of the hair on the scalp, face, and body. Scarring alopecia: Complete destruction of the hair follicles that causes scarring. Hair cannot regrow.
Treatment
Some people with alopecia may have hair that naturally grows back without treatment. More severe cases may need treatment or have permanent hair loss. Treatments for alopecia may include:
MinoxidilTopical corticosteroidsCorticosteroid injectionsAnthralinBimatoprost (a medication to help grow eyelashes)Contact immunotherapyMethotrexateJAK inhibitors
Chemotherapy can damage hair follicles, causing the hair to fall out on the head and body. How much hair someone loses during chemo depends on the person and the drug used. Not everyone will lose their hair during treatment, while others may experience hair thinning or complete hair loss. Hair loss may affect the scalp, pubic hair, arm and leg hair, eyebrows, and eyelashes. The scalp may also become itchy and sore.
Radiation therapy can also cause hair loss by damaging the hair follicles. The radiation dose can determine how much hair is lost or how permanent the loss is. Typically, hair loss starts a few weeks after treatment. Hair usually begins to grow back a few months after treatment. However, regrowth depends on hair follicle damage.
Treatment
Hair loss from cancer treatments is typically unavoidable. Still, your healthcare team may suggest using a cooling cap to help reduce your risk of hair loss. Other ways to help manage hair loss from cancer treatment include:
Avoiding styles that pull the hairGently coming the hair to avoid further loss and irritationCovering the head with scarves or turbansCutting the hair shorterWearing a wig
Stress can cause significant hair shedding, known as telogen effluvium. If your hair starts falling out months after a stressful situation, it is likely stress that’s to blame. Life events that can cause hair shedding include:
Giving birth
Experiencing high-stress situations like a sick relative, divorce, or losing a job
Having surgery
Losing more than 20 pounds
Recovering from illness (often with a high fever)
Stopping hormonal birth control pills
Treatment
The best way to treat stress-related hair loss is to manage stress. Typically stress-related hair loss stops after six to nine months, and hair returns to its usual thickness. If someone remains stressed, hair shedding may continue. Some ways to help manage stress include:
Deep breathing exercises
Getting enough sleep
Eating a balanced and nutritious diet
Exercising regularly
Meditating
Speaking with a mental health professional
Trichotillomania is an obsessive-compulsive disorder (OCD) that causes people to pull out their hair. People with hair-pulling disorder can damage the hair follicles and skin, causing hair loss.
Trichotillomania is often a coping mechanism for stress and anxiety that becomes a habit. Children are more likely to have trichotillomania, but it usually goes away without treatment. However, those with more severe trichotillomania may need help managing stress and cognitive behavioral therapy (CBT) to stop hair pulling.
Hair loss during pregnancy is not common, but it is possible. During pregnancy, people are more likely to have conditions that cause hair loss, like hyperthyroidism, hypothyroidism, and iron-deficiency anemia. Treating these conditions can help hair thickness return.
Postpartum hormonal changes and stressors are more likely to cause hair to fall out. After giving birth, a drop in estrogen levels can cause hair to start excessively shedding. The stress and trauma of birth can also cause hair shedding. Postpartum hair loss is typically the most noticeable after four months, but hair often grows back to its usual thickness in a year.
Constantly pulling the hair into tight styles can lead to hair loss called traction alopecia. This is when tight braids or ponytails pull the hair out and damage the hair follicle. Continuously coloring, perming, chemically relaxing, or heat styling can also damage hair and lead to hair thinning or loss. People may also lose hair when clothing rubs against the skin, which is known as frictional alopecia. This is more common on the legs.
How To Prevent Hair Damage
Traction alopecia is permanent, but it can be prevented by avoiding tight hairstyles that pull at the hair. Other ways to help prevent hair damage hair loss include:
Avoid weaves or hair extensions if possibleBrush hair when it is wet to prevent damageDo not get hair colored, permed, or relaxed too close together (wait at least two weeks between)Follow up shampooing with conditionerWait eight to 10 weeks between coloring touchups Wrap hair in a towel or air dry (avoid rubbing hair with a towel)Wear hair loosely pulled back
Hormonal imbalances related to polycystic ovary syndrome (PCOS) and birth control can lead to hair loss. PCOS hair loss is caused by the ovaries overproducing extremely high levels of androgens, causing hair loss on the temples and front of the scalp. Conversely, this hormone change may also cause excessive hair growth on the face and chest. People with PCOS hair loss typically take the oral medication spironolactone to help regrowth. Hormonal birth control may also be prescribed to help lower testosterone levels causing hair loss.
While not as common, people who stop taking birth control pills may experience temporary hormonal imbalances that thin hair. People going through menopause may also start to experience hair thinning as the body naturally drops estrogen levels.
The thyroid gland in your neck makes hormones necessary to regulate breathing, heart rate, mood, and digestion. When the thyroid doesn’t work correctly, it can cause hormonal imbalances that affect the entire body. People with thyroid disease may experience hair thinning, fine hair, and thinning eyebrows.
Both hyperthyroidism (an overactive thyroid) and hypothyroidism (an underactive thyroid) can cause hair thinning. This hair loss is typically temporary, and treating thyroid dysfunction can help regrowth. However, some thyroid medications can also cause hair loss.
STIs like syphilis can cause you to lose hair in patches on the scalp, eyebrows, and face. Treating syphilis with antibiotics should stop any additional hair loss. Hair should grow back after syphilis is treated.
Human immunodeficiency virus (HIV) can also indirectly cause hair loss. People with HIV are more at risk of iron-deficiency anemia and malnutrition, which can lead to hair loss.
Your body needs the right amount of vitamins and minerals to help healthy cells grow and function so that nutrient deficiencies can lead to hair loss over time. Eating a nutritious diet can help your body replenish the nutrients needed to keep your hair and body healthy.
Common nutrient deficiencies linked to hair loss include:
Biotin: A B vitamin that helps turn food into energy. Biotin is found in organ meats, eggs, fish, seeds, nuts, and sweet potatoes.
Iron: A mineral that helps make hemoglobin to move oxygen in red blood cells and hormones. Iron is found in meat, seafood, poultry, lentils, spinach, kidney beans, nuts, and iron-fortified grains.
Protein: A nutrient that helps grow and repair cells. Protein sources include animal products like meat, milk, eggs, and fish. Plant sources include beans, soy, legumes, and quinoa.
Zinc: A mineral that supports the immune system and helps make DNA and proteins. Zinc is found in oysters, meat, crab, lobsters, and zinc-fortified cereals.
Someone poisoned with arsenic, thallium, mercury, boric acid, and lithium can lose hair as a side effect. Ingesting large amounts of warfarin, an ingredient in rat poison, can also lead to hair loss. Taking toxic amounts of vitamin A and selenium can also lead to hair loss.
The only way to treat poison-induced hair loss is to diagnose what poison you have been exposed to. Hair typically regrows after someone stops poison exposure.
Some medications may cause your hair to fall out. Medications that may lead to hair loss and thinning include:
Antidepressants
Beta-blockers
Blood-pressure drugs
Blood thinners
Calcium channel blockers
Lithium, a mood stabilizer
Nonsteroidal anti-inflammatory drugs (NSAIDs), like ibuprofen
Retinoids, to treat skin conditions
If you are taking a new medication and notice your hair is falling out or thinning, reach out to your healthcare provider.
It’s a good idea to check with a healthcare provider if your hair seems to be falling out more than normal. Some hair naturally falls out daily, but excessive amounts may indicate a medical problem. There are a variety of treatment options that may be able to restore hair growth depending on the cause of your hair loss.
Hair loss can affect people differently depending on genetics, hormonal changes, or health conditions. Regardless of the cause, treatment to regrow hair is typically more effective if you catch hair loss early. Once the hair follicle is permanently damaged, hair can not grow back.
If your hair starts to thin or fall out in clumps, call your healthcare provider or dermatologist. They can help you figure out what is causing hair loss and how to help treat the root issue.
