19 Causes of Hair Loss—And What You Can Do About It

Too Much Vitamin A

Deficiencies of vitamins can cause hair loss (e.g., vitamins D & B7, biotin). However, overdoing vitamin A-containing supplements or medications can trigger hair loss as well, according to the American Academy of Dermatology. The Food and Drug Administration (FDA) recommends a Daily Value for vitamin A of 5,000 International Units (IU) per day for adults and kids over age 4; supplements can contain 2,500 to 10,000 IU. So any more than that and you could risk some strands falling out.

The good news: This is also a reversible cause of hair loss, and once the excess vitamin A is halted, hair should start growing normally again.

Stress or Illness

Stress or illness can cause hair loss—it's a process known as telogen effluvium, or the excessive shedding of hair induced by stress, Michelle Henry, MD, a dermatologist based in New York, previously told Health.

"Our bodies perceive mental stress the same way it perceives physical stress, and any dramatic stressor on the body can cause hair growth to become arrested," Dr. Henry said. "And when hair growth is arrested, it sheds." Specifically, when the body is stressed it releases the hormone cortisol, which can then affect the hair follicle and result in shedding or hair loss. That shedding typically occurs at least three months following a stressful event, Angelo Landriscina, MD, a Washington, DC-based dermatologist, previously told Health.

While preventing stress can help prevent stress-induced hair loss—that's not always easy. If you experience hair loss of any kind, check in with your health care provider. According to a 2017 review article in American Family Physician, if they determine that your hair loss is stress-related, they may recommend a treatment called minoxidil, a vasodilator that improves circulation around the hair bulb at the base of the hair follicle, to help grow hair back that you've lost. Also important: having patience and allowing time for hair regrowth.

Pregnancy

Pregnancy is one example of the type of physical stress that can cause hair loss (that and hormones). Pregnancy-related hair loss is seen more commonly after your baby has been delivered rather than during pregnancy. "Giving birth is pretty traumatic," explained Marc Glashofer MD, a dermatologist who sees patients at Schweiger Dermatology Group.

If you do experience hair loss after pregnancy, rest assured that your hair will grow back in a couple of months. "It's a normal thing and it will work its way out," Dr. Glashofer said.

Protein Deficiency

According to the American Academy of Dermatology, having too little protein in your diet can potentially lead to unwanted hair loss. It may also be a reason why, anecdotally speaking, people who are dieting may report some hair loss.

You can easily add more protein into your diet by incorporating more eggs, chicken, beans, and yogurt into your daily meal plan.

Female and Male–Pattern Baldness

You might already know about male–pattern baldness, a type of hair loss caused by a combo of genes and male sex hormones that usually makes the hair on a man's head recede at the temples, leaving an M–shaped hairline.

But hormone-related hairloss for females—or female–pattern baldness—is also a thing, according to the US National Institute of Health. This type of hair loss occurs (in both men and women) when the hair follicle shrinks so much over time that it doesn't grow new hair. In women, the symptoms of female–pattern baldness includes a widening of the center hair part, and, sometimes, coarser hair on the face.

The only FDA–approved treatment for female– and male–pattern hair is minoxidil (Rogaine), but if that doesn't work, your healthcare provider may prescribe oral medications such as finasteride (Propecia) that can halt hair loss or even cause some to grow; surgery to transplant or graft hair is also an option.

Genetics

"If you come from a family where women started to have hair loss at a certain age, then you might be more prone to it," said Dr. Glashofer. This would likely manifest as female–pattern baldness, with a widening hair part may widen and noticeable thinning of hair.

Women may benefit from minoxidil (Rogaine) to help grow hair, or at least, maintain the hair you have, Dr. Glashofer said. Rogaine is available over-the-counter and is approved for women with this type of hair loss. Talk to your healthcare provider before you use it—this medication, like all medications, can cause unwanted side effects.

Changing Hormones

The authors of a 2022 Journal of Cosmetic Dermatology research article explained that the change in hormonal balance that occurs when stopping or starting birth control pills, or around menopause may lead to hair loss. "The androgen (male hormone) receptors on the scalp become activated," explained Mark Hammonds, MD, a dermatologist with Scott & White Clinic in Round Rock, Texas. "The hair follicles will miniaturize and then you start to lose more hair," Dr. Hammonds said.

If a new Rx is a problem, talk to your healthcare provider about other birth control types. Stopping oral contraceptives can also sometimes cause hair loss, but this is temporary, said Dr. Hammonds.

Low Iron Levels

The American Academy of Dermatology lists iron deficiency as a potential cause of unwanted hair loss.

According to the National Heart, Lung, and Blood Institute (NHLBI), iron-deficiency anemia occurs when you don't have enough iron in your body—the symptoms of which include fatigue, tiredness, shortness of breath, or chest pain. To help remedy this, your healthcare provider might suggest iron supplements or other healthy lifestyle choices, like increasing your intake of both iron- and vitamin-C rich foods.

A Thyroid Condition

Thyroid conditions—like hyperthyroidism and hypothyroidism—can cause a range of hair issues. According to the American Academy of Dermatology, those include: thinning or missing eyebrows (mainly on the outer edge of the eyebrow), soft and fine hair with lots of shedding, thinning hair, and less hair on other body parts.

If you have experienced hair loss with a thyroid issue, the best bet is to speak with your healthcare provider about treatment possibilities—usually, treating the underlying cause first is essential to treating any other associated issues.

Alopecia Areata

Alopecia areata, a common autoimmune skin disease, causes hair loss on the scalp and other places on the body, according to the National Alopecia Areata Foundation (NAAF).

The NAAF says that the disease affects about 6.8 million people in the US, and people of all ages, sexes, and ethnicity groups can develop the condition.

There are different types of alopecia areata—and all will result in some form of hair loss, but there's no way to predict how much, or if it will return.

There are a variety of treatment options for alopecia areata, per the NAAF. Those include topical treatments, along with oral or injectable medications.

Lupus

Lupus is an autoimmune disease in which the immune system attacks the body's own healthy cells and tissues—including joints, skin, kidneys, heart, lungs, blood vessels, and brain— according to the US National Library of Medicine's MedlinePlus resource.

Hair loss is a common side effect of both lupus and the medications used to treat lupus, per the Lupus Foundation of America (LFA). Sometimes, with lupus, scarring on the scalp in the area of hair loss may inhibit hair from growing back; hair loss as a result of medication, however, may grow back when treatment is complete and medication stops.

That said, the LFA said that if you are experiencing hair loss, it's always wise to speak with your doctor before you try any treatments (like Rogaine, which is meant to treat a different type of hair loss) on your own.

Weight Loss

According to the American Academy of Dermatology, weight loss can result in thinning hair. This can happen even if the weight loss is ultimately good for you. The weight loss can put unnecessary stress your body, or may result in vitamin or mineral deficiencies. Loss of hair along with noticeable weight loss may also be a symptom of an eating disorder such as anorexia or bulimia.

This type of hair loss, too, will stop after weight normalizes and the body's nutritional needs are restored. "Sudden weight loss seems to shock the system and you'll have a six-month period of hair loss and then it corrects itself," said Dr. Hammonds.

Chemotherapy

Some of the drugs used to beat back cancer unfortunately can also cause your hair to fall out. "Chemotherapy is like a nuclear bomb," said Dr. Glashofer. "It destroys rapidly dividing cells. That means cancer cells, but also rapidly dividing cells like hair," Dr. Glashofer explained.

According to a 2022 research article published in Supportive Care in Cancer, once chemotherapy is stopped, your hair will grow back although often it will come back with a different texture (perhaps curly when before it was straight) or a different color. Researchers are working on more targeted drugs to treat cancer that could bypass this and other side effects.

Polycystic Ovary Syndrome

According to the 2022 research article from the Journal of Cosmetic Dermatology, polycystic ovary syndrome (PCOS) is a condition that causes hormone imbalance. An excess of androgens can lead to ovarian cysts, weight gain, a higher risk of diabetes, changes in the menstrual cycle, infertility, as well as hair thinning. Because male hormones are overrepresented in PCOS, women may also experience more hair on the face and body.

Treating PCOS can correct the hormone imbalance and help reverse some of these changes. Treatments include diet, exercise, and potentially birth control pills, as well as specific treatment to address infertility or diabetes risk.

Medication

According to a 2006 review article published in Current Drug Safety, many medication classes may promote hair loss. More common among them are certain blood thinners and the blood-pressure drugs known as beta-blockers. Other drugs that might cause hair loss include methotrexate (used to treat rheumatic conditions and some skin conditions), lithium (for bipolar disorder), nonsteroidal anti-inflammatory drugs (NSAIDs) including ibuprofen, and possibly antidepressants.

If your healthcare provider determines that one or more of your medications is causing hair loss, talk with them about either lowering the dose or switching to another medicine.

Over-Styling

According to the American Academy of Dermatology, vigorous styling and hair treatments can cause your hair to fall out. Examples of extreme styling include tight braids, hair weaves or corn rows, as well as chemical relaxers to straighten your hair, hot-oil treatments or any kind of harsh chemical or high heat. Because these practices can actually affect the hair root, your hair might not grow back.

In addition to avoiding these styles and treatments, the American Academy of Dermatology recommends using conditioner after every shampoo, letting your hair air dry, limiting the amount of time the curling iron comes in contact with your hair and using heat-driven products no more than once a week.

Compulsively Hair Pulling

Trichotillomania, classified as an "impulse control disorder," causes people to compulsively pull their hair out. "It's sort of like a tic, the person is constantly playing and pulling their hair," Dr. Glashofer said. Unfortunately, this constant playing and pulling can actually strip your head of its natural protection: hair, according to a 2021 review article published in Psychiatry Online. Trichotillomania often begins before the age of 17 and is four times as common in women as in men.

Some antidepressants may be effective as treatment, and behavioral modification therapy is another option, according to the 2022 Psychiatry Online review article.

Age

It's not uncommon to see hair loss or thinning of the hair in women as they enter their 50s and 60s, said Dr. Glashofer.

Experts don't recommend that this condition be treated, said Dr. Hammonds. That leaves women with cosmetic approaches such as scarves, wigs and hair styled so as to cover up thin spots. That said, there are also plenty of tricks to prevent hair breakage and ways to keep your hair looking shiny and healthy in your 50s and beyond, such as moisturizers and avoiding over-styling.

Anabolic Steroids

If you take anabolic steroids—the type abused by some athletes to bulk up muscle—you could lose your hair. Anabolic steroids can have the same impact on the body as polycystic ovary disease (PCOS), because the mechanism is the same, said Dr. Hammonds. Hair loss should improve after going off the drug.