Hereditary Hair Thinning or Androgenetic Alopecia

Hereditary thinning is known by many different names:

  • androgenetic, or androgen-dependent alopecia
  • common baldness
  • diffuse hair loss
  • male or female pattern baldness

Hereditary thinning is, by far, the most common kind of baldness. About half of all men over the age of 40 experience hair loss due to male pattern baldness. In fact, it is so common that many people think it is a normal part of the aging process.

Although hereditary baldness is not as common among women, as many as 20 million American women and 30 percent of all Caucasian women are affected by female pattern baldness.

Causes of Hereditary Hair Thinning

People who inherit genes for baldness (or thinning) from either parent are likely to experience hair loss or thinning during their adult life.

Androgenetic alopecia is also androgen dependent. Androgens are the hormones that stimulate the development of male sex characteristics. Testosterone is one type of androgen. Androgens induce alopecia by shortening the anagen phase and increasing the number of hairs that are in the telogen phase. Some women with androgenetic alopecia have abnormally elevated levels of androgens in their bodies as a result of underlying ovarian or adrenal gland disorders.

Signs & Symptoms of Hereditary Hair Thinning

Men with androgenetic alopecia typically have a receding hairline and moderate to extensive loss of hair, especially on the front and top of the head. The remaining hair tends to feel a little finer and shorter than normal. Male pattern baldness can start as early as the teenage years.

Women with androgenetic alopecia experience overall thinning of their hair. For example, where there used to be five hairs, there may only be two. Most of the hair that's lost is on the crown of the head or at the hairline. Female pattern baldness usually starts around age 30 and becomes noticeable around age 40.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 02 Feb 2001

Last Modified: 17 Sep 2015