What Causes Hair Loss?

Many things, from genetics to an underlying health problem, can trigger hair loss in men. Learn about possible hair loss causes so you can take action against thinning hair. 

If you are experiencing hair loss, you may assume that your genes are the cause and that nothing can be done. But many factors can cause too much hair to fall out, including some you might find surprising — all those cheeseburgers and fries, that blood pressure medication your doctor prescribed, or the surgery you had a few months ago.

While some types of hair loss are permanent, others are temporary, and once the cause of the hair loss is treated or removed, hair will grow back.

Genetics and Male Pattern Baldness

For many men, hair loss is genetic. This type of hair loss is called androgenetic alopecia, or as it’s commonly known, male pattern baldness. This can start as early as puberty. "By the age of 25, 25 percent of all men will be affected by male pattern hair loss. By age 40, this figure increases to approximately 50 percent," says Paul J. McAndrews, MD, clinical professor in the department of dermatology at the University of Southern California School of Medicine in Los Angeles.

"Androgenetic alopecia, the most prevalent type of hair loss for which patients seek professional treatment today, is a condition of aging that everyone experiences to some extent," says Dr. McAndrews. A patient’s genetics will determine the severity and extent of hair loss. And don't just blame Dad — male pattern baldness can be inherited from Mom, too.

If your hair loss is genetic, talk to your doctor about treatment options. Prompt treatment can often help prevent more hair loss and sometimes can stimulate new growth.

Hidden Hair Loss Causes

A number of health problems can trigger hair loss, including:

• A thyroid condition
• Insufficient protein in the diet
• Hormone imbalance (such as underactive or overactive thyroid)
• Fungal infection (such as ringworm of the scalp)
• Lupus
• Diabetes
• Undergoing major surgery
• Excessive vitamin A
• Iron deficiency (rare)
• Vitamin D deficiency (a possible cause that is still being researched)

Fortunately, these hair loss causes can generally be treated. Depending on your health issue, keeping hormones in balance, ensuring proper nutrition, taking medications as your doctor recommends, and maintaining tight control of blood glucose levels can help stop hair loss, and hair will usually start to grow back.

Hair Loss as a Medication Side Effect

Some medications can trigger hair loss. Hair loss is a well-known side effect of chemotherapy treatment for cancer. But some common medications may also lead to hair loss, including:

• Anticoagulants that thin the blood
• High blood pressure medication
• Gout medication
• Antidepressants
• Birth control pills

By switching to a different medication under your doctor’s guidance, you can usually stop this kind of hair loss.

Hair Loss Due to Stress and Lifestyle

Your lifestyle, especially one characterized by high stress levels, not getting the proper nutrition, and significant weight loss, can play a major role in your health and in the health of your hair, says Edwin S. Epstein, MD, president of the International Society of Hair Restoration Surgery.

Although experts don't know the exact process, there is a clear relationship between high levels of stress and hair loss. "Somehow stress has an effect on the hair cycle. Typically about 90 percent of hairs are in a growing stage and about 10 percent are in a resting stage, and it's these resting-stage hairs that shed,” explains Dr. Epstein. Stress seems to prompt more of the growing hairs to go into the resting phase and then fall out. The good news is that this type of hair loss is temporary; after the hair falls out, a new hair usually will replace it.

To prevent stress-induced hair loss, maintain a healthy lifestyle with regular exercise and a nutritious diet. See a dermatologist if you have questions or concerns about your hair loss to get the right diagnosis and an effective treatment plan.