Women and Hair Loss: Causes

Medically Reviewed by Poonam Sachdev on August 27, 2023
9 min read

Female hair loss happens when a woman, or anyone who was identified as female at birth, loses more hair than normal. About half of all women will have hair loss at some point in life. Most start to notice it in their 50s or 60s, but it can happen at any age and for a variety of reasons. 

To understand why it happens, it's important to know how hair grows. Hair growth starts when new cells form within your follicles, the pores in your skin from which hair grows. These new cells clump together and start to become hard, forming a strand of hair. Hair grows in three cycles, or phases:

  • Anagen phase. About 90% of the hair on your head is in this active growth phase at any time, which can last 2-8 years. Hair grows about 6 inches a year for most people.
  • Catagen phase. This short transition phase usually lasts 2-4 weeks. Hair stops growing and separates from its blood supply.  
  • Telogen phase. During this cycle, which lasts 2-4 months, the hair rests. Eventually, it sheds and the growth cycle begins again. 

Because hair is constantly falling out and growing, hair loss often goes unnoticed. You're more likely to notice it when a lot of hair enters the resting phase at the same time or if hair roots become damaged during the growth process.

Things that interfere with the growth cycle -- like medications, illnesses, infections, or chemicals -- have the potential to stop hair from being formed the right way. Beyond that, age, hormones, stress, and even the way you style your hair can lead to hair loss.

Most people lose anywhere from 50 to 100 strands of hair each day, according to the American Academy of Dermatology. On days you wash your hair, you might lose up to 250 strands. 

But if you lose a lot more than that, you may have noticeable hair loss. 

Symptoms of hair loss include:

  • When you comb or brush your hair, more than normal is left in the comb.
  • You see lots of hair left on your pillows, towels, or clothes, or in the shower drain.
  • Your hair looks thinner.
  • Patches of scalp are visible.

While male hair loss tends to affect the forehead or the crown of the head, female hair loss often leads to thinning on the top third to half of the scalp. Your part may gradually become wider, you might see more of your scalp when your hair is pulled back, or your ponytail could be less full.


The most common cause of female hair loss worldwide is female pattern baldness, which is also called androgenetic alopecia . This type of hair loss has a strong genetic component and can be inherited from either your mother or father. It affects about 30 million American women. In men, it's called male pattern baldness. 

It usually happens when you're in your late 50s or 60s. But you may start to notice it as early as your late teens -- and the earlier it starts, the more serious it tends to be. Hormone changes during menopause can also contribute to this type of baldness. 

With this type of hair loss, your follicles gradually shrink and the growth cycle is shortened. You shed hair normally. But new hairs grow back finer and thinner. After a while, some follicles may stop producing hair.  

You're unlikely to lose all of your hair with female pattern baldness. But without treatment, symptoms may get worse over time.

Other main categories of hair loss include:

Anagen effluvium

This is the name for hair loss caused by medications that harm your hair follicles. Radiation and chemotherapy treatments for cancer can be toxic to follicles, causing your hair to fall out within the first few weeks after you start treatment. Hair regrowth usually begins within a few months after you finish treatment.

Telogen effluvium

You get this form of hair loss when lots of follicles get to the telogen phase, or resting period, but don't start the active growth phase again. So when hairs are shed, they're not replaced. It can result from:

  • Some illnesses
  • Physical or emotional stress
  • A diet low in certain vitamins or minerals
  • Some medications
  • Hormones, such as from pregnancy

It doesn't usually cause you to lose all your hair. It's most often temporary, but sometimes it can last for months or years.

If your hair loss is sudden, it's likely caused by something other than your genes, like a medical condition.

Many conditions can bring on hair loss. Some of the most common are pregnancy, thyroid disorders, and anemia. Others include:

  • Ringworm, which spreads from person to person and can cause bald spots
  • Other skin conditions such as psoriasis and seborrheic dermatitis
  • Scalp infections
  • Sexually transmitted infections
  • High fever
  • An autoimmune disease called alopecia areata, in which your own immune system attacks your follicles, leaving round bald patches
  • Scarring alopecia, most often seen in Black women, in which hair starts falling out from the middle of the scalp and fans out, leaving areas of the scalp smooth and shiny
  • Diabetes

Sometimes hair loss is a sign of a condition called hyperandrogenism, which happens when your body makes too many androgens (male hormones). In women and others with female reproductive organs, its most common cause is polycystic ovary syndrome (PCOS). Along with hair loss, other signs of PCOS include weight gain, acne, and irregular periods. It's one of the most common causes of infertility.

Certain medications can lead to hair loss in some people, too. They include birth control pills, blood thinners, and some steroids.

You can have hair loss as a result of physical stress, like when you give birth or have surgery, or intense emotional stress, like a death in the family, divorce, or unemployment.  Hair loss can happen a couple of weeks to 6 months after any stressful experience.

This type of hair loss is usually temporary. Once the stress goes away, your hair may get back to normal in 6-9 months.


Sometimes, people react to stress by plucking hairs from their head, eyebrows, and other places on their body. This disorder is called trichotillomania. It’s a way for some people to ease tension, frustration, and other uncomfortable feelings. If you're embarrassed by a need to pull your hair or can't stop pulling it, talk to your doctor. Symptoms can get worse over time. Once you stop plucking hairs, they'll probably regrow. 


If you lose more than 15 pounds in a short time, you might lose some of your hair as your body reacts to the shock. Other reasons for hair loss include:

  • A shortage of iron, protein, or other nutrients
  • Too much vitamin A (usually from supplements)
  • A shortage of vitamin D (which you can correct by taking supplements) 
  • Anorexia (severely restricting yourself from food) or bulimia (throwing up on purpose after eating)

Several types of hormonal changes can lead to hair loss. They include:

Menopause. You can lose hair during menopause as your estrogen and progesterone levels drop. Also, because hair follicles shrink during this time, your hair might be thinner, fall out easier, and grow more slowly. 

 If you're going through menopause, talk to your doctor about ways to maintain or regrow your hair.

Pregnancy and childbirth. Pregnancy, and especially giving birth, can lead to hair loss. You're most likely to see hair loss about 3 months after giving birth. That's because your estrogen levels drop after childbirth. Your hair may fall out in clumps. If you're losing hair while pregnant, ask your doctor if you might have a dietary deficiency. 

Hair usually regrows when your hormones get back to normal. Your hair can regain its usual fullness 6 to 9 months after childbirth. 

Age. Hormonal changes as you age can cause hair loss. Hair growth naturally slows with age, so you may notice thinning. Some follicles eventually stop growing hair. If you think you have age-related hair loss, talk to your doctor about treatment early on.


Anyone can have androgenetic alopecia (pattern baldness). These hair changes can make it hard to maintain how you want to look, especially if you're transgender or nonbinary (which means you don't identify as fully male or female). You may want to shift where hair grows (or doesn't) to reflect your affirmed gender. 

Taking hormones can change hair growth all over your body. Masculinizing hormone therapy (taking testosterone) may cause hair loss within a year, and the effects aren't reversible if you stop hormone treatment.

Some people who take feminizing hormones, like estrogen or antiandrogens, notice hair growth on their scalps (but the growth may not be significant, so you may need other treatments for hair loss). Scalp hair loss may slow down within 1-3 months, and you may have less facial and body hair after 6-12 months of treatment. Overall results could take 1-2 years.



Traction alopecia is a type of hair loss that's brought on by the way you style your hair. Hairstyles like cornrows, braids, or tight ponytails can cause it. Some signs of traction alopecia include hair loss in patches where the hair was pulled and shorter strands of hair near the forehead.

Other styling habits that can lead to breakage and thinning hair include:

  • High heat from blow dryers or flat irons
  • Harsh chemicals from bleach, perms, or other products
  • Tightly pulled hair from clips, bands, or pins
  • Over-shampooing or brushing and combing too much, especially when your hair is wet

With most of these issues, your hair can grow back. But if your follicles become damaged, the hair loss may be permanent. See your dermatologist if you notice this type of hair loss. The sooner you start treatment, the better the chances for hair regrowth. 

When you see a doctor to see what's causing your hair loss, they’ll probably start with a physical exam and ask about your diet, family history, and medical history. They may ask whether any of your relatives have hair loss.

They can also do tests such as:

Blood tests.  This helps them look for conditions like thyroid problems or low iron.

Light microscopy. Your doctor may use a lighted microscope to look for any hair shaft disorders.

Pull test. For this test, they gently pull on a chunk of your hair to see how many strands come out.

Scalp exam. Looking at your scalp lets your doctor check for any infections or swelling and see where your hair’s falling out. 

Biopsy. Your doctor gently scrapes skin samples from your scalp and sends them to a lab for testing.

The treatment for hair loss depends on what's causing it. If a medical condition is the cause, treating that condition should help with the hair loss. If it's caused by a medication, your doctor can change your drug or the dosage. 

Treatments may include:

Medications. Minoxidil (Rogaine) is a topical medication (the type you apply to your scalp) approved by the FDA for female pattern hair loss. It's is available over the counter as 2% and 5% solutions. It takes about 6-12 months of this once-daily use foam treatment to see results. 

The medication works by prolonging the growth phase of hair, giving your hair more time to grow out. 

If you're pregnant, planning to become pregnant, or breastfeeding, ask your doctor before taking minoxidil. It may be harmful to your unborn baby and can pass through breast milk to a nursing infant.

Spironolactone is another medication your doctor may prescribe for hair regrowth and to keep hair loss from getting worse. It stops the action of male hormones called androgens.

Supplements. If you have a deficiency, your doctor may suggest multivitamins or supplements like iron and biotin. Don't take any supplement before checking with your doctor. They may interact with other medications or supplements you take.

Hair transplants. This is a procedure in which your doctor removes hair from a part of your scalp where hair growth is full and implants it into an area where hair is thinning.

Laser devices. The FDA has approved a few laser treatment devices to treat hair loss at home. They work by stimulating hair growth. But we need more studies into their safety and effectiveness for long-term use.

All treatments work best when you start them early. If you notice hair loss, talk to your doctor as soon as you can.