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

Thinning hair, shedding hair, and hair loss affect all individuals, and it's no more or less demoralizing for anyone. There are different reasons behind hair loss—causes range from a vitamin deficiency to taking too much vitamin A to chronic underlying health conditions.

Luckily, there are many ways to treat hair loss, depending on the cause. Here are 18 reasons why you might be seeing less hair on your head—and what you can do about it.

Age

It's not uncommon for people to see hair loss or thinning of the hair as they get older.

If you have age-related hair loss, you can use cosmetic approaches such as hair coverings or hairstyles to cover up thin spots.

There are also plenty of tricks to prevent hair breakage and ways to keep your hair looking shiny and healthy as you age. However, things to avoid include practices such as:

• Not using hair care products designed for your hair type
• Overusing heat tools like blow dryers and curling irons
• Tugging while you comb or brush your hair
• Wearing hairstyles that pull on your hair

Alopecia Areata

Alopecia areata, a common autoimmune skin disease, causes hair loss on the scalp and other places on the body. People of any age, sex, or ethnic group can develop the condition. There are different types of alopecia areata—and all will result in some form of hair loss.

There's no way to predict how much or if the hair will return. However, there are various treatment options for alopecia areata, like topical treatments, oral or injectable medications, and ultraviolet light therapy.

Anabolic Steroids

If you take anabolic steroids—the type abused by some athletes to bulk up muscle—you could lose your hair. Steroids are linked to endocrine regulation, which is responsible for hormones that help the body's functioning. When a person takes steroids, the substances can affect the hormones for hair growth regulation.

Changing Hormones

Researchers explained that starting or stopping birth control pills and enduring menopause may lead to hair loss. That's because of the change in the hormonal balance that occurs during those events. 

Talk to a healthcare provider about other birth control types if a new prescription leads to side effects like hair loss.

Chemotherapy

Some drugs used to beat cancer can cause your hair to fall out. However, your hair will grow back once chemotherapy stops. It can come back with a different texture—perhaps curly when it was straight previously—or a different color.

Compulsive Hair Pulling

Trichotillomania is an impulsive control disorder that causes people to pull their hair out compulsively. The condition often begins before age 17 and is four times as common in females than in males.

The constant playing and pulling can strip your head of its hair. However, there are treatments that may be helpful for trichotillomania. Some antidepressants may be effective, and behavioral modification therapy is another option.

Female and Male-Pattern Baldness

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

There's also hormone-related hair loss for females, or female–pattern baldness. That hair loss occurs when the hair follicle shrinks so much over time that it doesn't grow new hair.

The symptoms of female–pattern baldness include widening the center hair part and, sometimes, coarser hair on the face. Often, that type of hair loss can be genetic.

Rogaine (minoxidil) is the only FDA–approved treatment for female– and male–pattern hair loss. Rogaine is available over-the-counter but talk to a healthcare provider before you use it. Like all medications, Rogaine can cause unwanted side effects.

If that doesn't work, a healthcare provider may prescribe oral medications, such as Propecia (finasteride), which can halt hair loss. Surgeries to transplant or graft hair are also options.

Low Iron Levels

Iron deficiency is a potential cause of unwanted hair loss. Iron-deficiency anemia occurs when you don't have enough iron in your body. The symptoms include fatigue, tiredness, shortness of breath, or chest pain. 

To help remedy an iron deficiency, a healthcare provider might suggest iron supplements or other healthy lifestyle choices. Those may include increasing your intake of both iron- and vitamin-C-rich foods.

Lupus

Lupus is an autoimmune disease in which the immune system attacks the body's healthy cells and tissues. It affects the joints, skin, kidneys, heart, lungs, blood vessels, and brain.

Hair loss is a common side effect of lupus. With lupus, scarring on the scalp during hair loss may inhibit hair from growing back in some cases.

If you are experiencing hair loss, it's always wise to speak with a healthcare provider before you try any treatments (like Rogaine) on your own.

Medications

Different medication classes may promote hair loss. They include medications such as:

• Antidepressants
• Blood thinners and blood-pressure drugs
• Methotrexate, for rheumatic conditions and some skin conditions
• Lithium, for bipolar disorder
• Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen

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

Over-Styling

Vigorous styling and hair treatments can cause your hair to fall out. Examples of extreme styling include:

• Chemical relaxers to straighten your hair
• Corn rows
• Hair weaves
• Hot-oil treatments
• Tight braids
• Any kind of harsh chemical or high heat

Because those practices affect the hair root, your hair might not grow back.

In addition to avoiding those styles and treatments, use conditioner after shampooing and letting your hair air dry. Additionally, limit the time the curling iron comes in contact with your hair, and use heat-driven products no more than once a week.

Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a condition based on a hormone imbalance. The hormone imbalance is partially due to excess androgen, a sex hormone. This excess can lead to physical side effects, including hair loss in the form of hair thinning.

Because androgen is overrepresented in cases of PCOS, those people may also experience more hair on the face and body. Other symptoms of PCOS include:

• Changes in the menstrual cycle
• Higher diabetes risk
• Infertility
  
• Ovarian cysts
• Weight gain
  

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

Pregnancy

Pregnancy is one type of physical stress that can cause hair loss along with hormones. Pregnancy-related hair loss is seen more commonly after your baby has been delivered rather than during pregnancy. If you experience hair loss after pregnancy, rest assured that your hair will grow back. It just may take some time—from a few months to a few years.

Protein Deficiency

Having too little protein in your diet can lead to unwanted hair loss. It may also be why, anecdotally speaking, people who are dieting may report some hair loss.

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

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.

While limiting stress can help prevent hair loss—that's not always easy. If you experience hair loss, check in with a healthcare provider. If a healthcare provider determines that your hair loss is stress-related, they may recommend minoxidil.

A Thyroid Condition

Thyroid conditions—like hyperthyroidism and hypothyroidism—can cause various hair issues. Those include:

• Less hair on other body parts
• Soft and delicate hair with lots of shedding
• Thinning or missing eyebrows, mainly on the outer edge of the eyebrow
• Thinning hair

The best bet is to speak with a healthcare provider about treatment possibilities. Usually, treating the underlying cause first is essential for treating any other associated issues.

Too Much Vitamin A

Deficiencies of vitamins, like biotin and vitamins D and B7, can cause hair loss. However, overdoing vitamin A-containing supplements or medications can also trigger hair loss.

The daily recommended amount for vitamin A is 5,000 International Units (IU) for adults and children over the age of four years. Supplements can contain 2,500 to 10,000 IU. Any more than that, you could risk some strands falling out.

The good news is too much vitamin A is also a reversible cause of hair loss. Once the excess vitamin A is halted, hair should start growing normally again.

Weight Loss

Weight loss can result in thinning hair. That can happen even if the weight loss is ultimately good for you. Weight loss can stress your body unnecessarily or may result in vitamin or mineral deficiencies.

Also, loss of hair and noticeable weight loss may also be symptoms of an eating disorder such as anorexia or bulimia.

Hair loss following weight loss can stop after weight normalizes and the body's nutritional needs are restored.

A Quick Review

The thinning or shedding of your hair can be unnerving and disheartening. Some of the reasons for hair loss include age, stress, pregnancy, and medications. If you are experiencing hair loss, consult a healthcare provider to determine the cause.