The Common Causes of Excessive Hair Loss in Men

Man looking at hair loss in mirror.


If you're starting to go bald, it could feel like you're losing a piece of your identity. Understanding the cause of your excessive hair loss can help you decide if treatment options are right for you or if your hair will grow back. Here are some common causes of hair loss in men.

Surgery or Illness

If you recently underwent a major surgery or are recovering from a serious illness, hair loss is normal. Many people experience dramatic levels of hair loss some weeks after major surgery or after an illness. While the level of hair loss may appear excessive, it is really no more than a reaction to a specific event and hair will return to normal after a period of time.


Some anticoagulants and many chemotherapy drugs used in cancer treatments are well known for causing hair loss. Hair usually returns once the medication stops. Some anti-depressants also may result in hair loss and too much vitamin A can have the same effect.

Hormonal Imbalances

Testosterone is a hormone that all men have heard of. It's responsible for deeper voices, muscular growth, and sex drive, among other things. When your body converts testosterone to the less useful dihydrotestosterone (DHT), you can experience hair loss. DHT attacks and shrinks hair follicles and may result in hair thinning or hair loss.

Thyroid Issues

Patients with hyperthyroidism or hypothyroidism often experience hair loss due to a speeding up of the conversion of testosterone to DHT. Even people who are undergoing thyroid treatment are not immune from the hair loss associated with their condition.


If you've been under a lot of pressure at work or at home, you might be able to blame your hair loss on stress. Excessive physical or emotional stress can cause hair to stop growing normally, falling out two or three months later. Luckily, hair loss due to stress is usually not permanent.


Alopecia areata is a condition that is also caused by stress. It causes hair to fall out in round patches on the scalp and elsewhere on the body due to your immune system attacking hair follicles. About five percent of people with alopecia will lose hair on their entire scalp. Typically, hair grows back, but it's common for hair loss to reoccur.

Certain fungal infections can all result in hair loss. Losing your hair may also signal some underlying problem like diabetes or lupus. As it is not always possible to assess the cause of rapid or excessive hair loss, it is always worth seeking medical advice to diagnose the cause of your hair loss.

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Article Sources

  • American Academy of Dermatology. Alopecia Areata: Overview.