Male Pattern Baldness Causes

While doctors don’t perfectly understand what causes baldness, they do know that it occurs as hair follicles on the scalp shrink over time. The result is shorter, thinner hair–and eventually, no hair at all.

The typical hair follicle will grow hair for two to six years, a stage called “anagen.” Eventually the hair falls out, and the follicle takes a break in a stage called “telogen.” The average person loses 50 to 100 hairs a day in this manner, which barely makes a dent in the estimated 100,000 hairs in the scalp (Mayo Clinic, 2010). A shortening of the growth cycle is commonly what causes baldness, along with a tendency for hairs to become thinner and more superficially planted in the scalp.

Causes of Baldness: Aging

Aging and baldness are inextricably linked, as most men begin to experience some baldness around middle age. Genetics and hormones are also key factors in what causes baldness, affecting when you will lose hair and how much. According to the U.S. National Library of Medicine (2011), 50 percent of men over the age of 50 have experienced some degree of hair loss.

Causes of Baldness: Hormonal Changes

Hormonal changes can be a cause of baldness, but hormonal hair loss may be temporary, rather than a sign of male pattern baldness. An underactive thyroid gland or an overproduction of testosterone affect hormone levels in men and may result in balding.

Other Causes of Baldness

While aging coupled with a genetic predisposition are the most common hair loss causes, other factors can contribute to hair loss and may add to or worsen male pattern baldness. The following may cause baldness:

  • Disease, particularly diabetes
  • Hair treatments that cause hair to break or fall out
  • Medications, in particular those for arthritis, depression, gout and heart problems
  • Poor diet, especially an iron deficiency
  • Scalp infection
  • Trichtotillomania, a hair-pulling mental disorder.


Mayo Clinic Staff. (2010). Hair loss. Retrieved February 23, 2011, from

Medline Plus. (2009). Male pattern baldness. Retrieved February 23, 2011, from

U.S. National Library of Medicine: Genetics Home Reference. (2011). Androgenetic alopecia. Retrieved February 23, 2011, from