Mental Floss 2016-10-25T14:11:58+00:00 2014-01-09T14:30:00+00:00 2014-01-09T14:30:01+00:00 What Causes Baldness? DeAnna Kerley

If you’ve got a receding hairline, don’t be so quick to blame it on your baseball caps or your grandpa.

Studies show that genetic factors mostly determine a person’s predisposition for hair loss. Humans have 46 chromosomes of DNA, and two of these chromosomes determine the sex of a person: the X chromosome and the Y chromosome. Women have two X chromosomes, while a man has an X chromosome and a Y chromosome. These chromosomes are passed from the parents to their child. The gene affecting hair loss is located on the X chromosome.

Since a male child can only inherit an X chromosome from his mother, it is often said that a man can determine the likelihood of becoming bald by looking at his mother’s father. If a man’s maternal grandfather expresses hair loss, then that man may also experience hair loss within his lifetime.

But it is possible to have a grandpa with a full head of hair and still become bald. This is because hair loss is only partially hereditary; a man may only have a 50/50 chance of inheriting baldness from his mother, since his mother has two X chromosomes. Additionally, a joint 2008 study conducted by McGill University, King's College London and GlaxoSmithKline Inc. pinpointed a small area on Chromosome 20 called 20p11 that is associated with male pattern baldness. Research is still being done as to the “why”, but so far it is known that men with this particular genetic variant are seven times more likely to lose their locks than those who do not carry it.

Still, genetics are not the only piece of the puzzle. Diet, exercise, and stress levels can also cause baldness. And while some may view baldness as a mark of distinction and maturity, others have tried all sorts of homemade remedies to stimulate hair growth. In ancient Egypt, doctors recommended mixtures of fats from hippos, crocodiles, tomcats, snakes, and ibex. One medical text even suggests boiling porcupine hair in water and applying it to the scalp for four days.

In the United States during the 19th century, salesmen and sideshow performers marketed phony concoctions of snake oils that supposedly reversed hair loss. Later in the 20th century, manufacturers developed a Thermocap device that worked to stimulate hair follicles. Unfortunately, the few individuals who wore the Thermocaps looked like characters from Coneheads. Much like Viagra, Minoxidil (the active ingredient in Rogaine) was originally intended as a possible treatment for high blood pressure. When the hair growth side effect was discovered, Big Pharma changed its marketing strategy.

January 9, 2014 - 9:30am