Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff. Lauren Boga Bob here with another classic episode for you. Former host Christian Sager is explaining what's too many folks a pressing consideration as they get older. Why do some people go bald? Hi? I'm Christian Sager and this is brain stuff. Have you ever heard that if your maternal grandfather went bald, that you will to? Or what about
the one we're getting? A scalp massage will send more blood to your head and cause your hair to grow back. Some people also claim that if you shave your hair, it will grow back even fullier than before. Sorry to break it to you, but all of these are bogus myths. As long as men have been losing their hair, they've been trying to figure out what causes baldness and how
they can cure this sign of aging. In fact, it's estimated that forty million Americans are losing their hair, and that's men and women, and all of those people are spending more than one billion dollars a year on everything from hair transplants to two pays and spray on hair. Now hair, real hair grows just under the skin on our heads from the close to one hundred thousand follicles there.
This growth happens in three phases, the antigen phase where it's growing, the catagen phase in between, and the telligen phase where it falls out. And hair falling out is totally normal. We should lose fifty to one hundred hairs every day as part of the intelligence cycle. But if more hair falls out then is replaced, you are probably balding. If the hair that grows back is thinner than what fell out, you're probably balding. And if it starts falling
out in clumps, oh yeah, you are balding. But hey, take comfort that you are not alone. My friends, by age thirty, a quarter of all men have already started to lose their hair. What's weird is why do humans go bald in the first place. Baldness is actually pretty rare in other animals, and hair serves a lot of important purposes. It protects our heads from the sun, maintains our body heat when we're cold, and may even attract mate. Some researchers think it suggests a dominant status or a
sign of maturity in different societies. In fact, a paper from the journal Social Psychological and Personality Science found evidence that women find completely bald men more attractive than partially bald ones. The study also found that baldness was highly associated with two traits, dominance and strength. So if you're starting to lose your hair, maybe you should take action, shave it all off and show the world what a tough, assertive man you are. To understand baldness a little better,
let's look at the different types that occur. First. The most common type is called and dro genetic alopecia, otherwise known as male pattern baldness. It's related to our inherited genetic predisposition from both of our parents. This affects how sensitive we are to a hormone called die hydro testosserone,
hereafter referred to as d HT. For most guys, five percent of their testosterone is converted into d h T. If you're sensitive to d h T, it acts like a toxin on your hair follicles, producing thinner, weaker, almost colorless hair until hair production in the follicle simply stops.
Researchers have also found that male pattern baldness also causes men to have an abnormal amount of a protein lipid called prostaglandin D two Some dermatologists even think that men could regrow their hair if this inhibiting protein were removed. Other types of baldness include the female pattern baldness that occurs in some women post menopause, an autoimmune disorder called alopecia ariata, and a condition called telligent effluvium that makes
your hair fall out faster than normal. People can also have brittle hair from hair shaft defects, or in rare cases, they may even pull out their own hair compulsively if they have a disorder called trick atilla mania. You think that sounds scary. You can also lose your hair from illnesses, fungal infections, burns, chemical applications, medications, and of course, cancer treatments like chemotherapy. Smoking is also reported to increase the
risk of baldness. You should definitely see your doctor if your hair starts falling out in clumps or if you get a burning, itching irritation on your scout. Today's episode was written by Christian and produced by Tyler Clang. If you miss Christian, check out his new podcast dissecting pop culture. It's called super Context and it's available wherever you get your podcasts. And of course For more on this and lots of other Harry topics, visit our home planet, how stuff Works dot com.