1 00:00:02,040 --> 00:00:10,040 Speaker 1: Welcome to brain stuff from how stuff works. Hi, I'm 2 00:00:10,119 --> 00:00:13,160 Speaker 1: Christian Saga and this is brain stuff. Have you ever 3 00:00:13,200 --> 00:00:16,119 Speaker 1: heard that if your maternal grandfather went bald that you 4 00:00:16,200 --> 00:00:18,799 Speaker 1: will to? Or what about the one we're getting? A 5 00:00:18,880 --> 00:00:21,439 Speaker 1: scalp massage will send more blood to your head and 6 00:00:21,520 --> 00:00:24,840 Speaker 1: cause your hair to grow back. Some people also claim 7 00:00:24,920 --> 00:00:27,040 Speaker 1: that if you shave your hair, it will grow back 8 00:00:27,200 --> 00:00:30,280 Speaker 1: even fullier than before. Sorry to break it to you, 9 00:00:30,320 --> 00:00:33,760 Speaker 1: but all of these are bogus myths. As long as 10 00:00:33,800 --> 00:00:36,120 Speaker 1: men have been losing their hair, they've been trying to 11 00:00:36,159 --> 00:00:39,480 Speaker 1: figure out what causes baldness and how they can cure 12 00:00:39,520 --> 00:00:43,559 Speaker 1: this sign of aging. In fact, it's estimated that forty 13 00:00:43,760 --> 00:00:48,159 Speaker 1: million Americans are losing their hair, and that's men and women, 14 00:00:48,600 --> 00:00:51,240 Speaker 1: and all of those people are spending more than one 15 00:00:51,440 --> 00:00:55,320 Speaker 1: billion dollars a year on everything from hair transplants to 16 00:00:55,480 --> 00:00:59,480 Speaker 1: two pays and spray on hair. Now, hair, real hair 17 00:01:00,160 --> 00:01:02,320 Speaker 1: is just under the skin on our heads from the 18 00:01:02,360 --> 00:01:06,440 Speaker 1: close to one hundred thousand follicles there. This growth happens 19 00:01:06,480 --> 00:01:10,440 Speaker 1: in three phases, the antigen phase where it's growing, the 20 00:01:10,560 --> 00:01:14,160 Speaker 1: catagen phase in between, and the telligen phase where it 21 00:01:14,200 --> 00:01:18,200 Speaker 1: falls out and hair falling out is totally normal. We 22 00:01:18,200 --> 00:01:22,080 Speaker 1: should lose fifty to one hundred hairs every day as 23 00:01:22,160 --> 00:01:26,040 Speaker 1: part of the intelligence cycle. But if more hair falls 24 00:01:26,080 --> 00:01:29,800 Speaker 1: out then is replaced, you are probably balding. If the 25 00:01:29,840 --> 00:01:32,360 Speaker 1: hair that grows back is thinner than what fell out, 26 00:01:32,640 --> 00:01:36,400 Speaker 1: you're probably balding. And if it starts falling out in clumps, 27 00:01:36,600 --> 00:01:40,640 Speaker 1: oh yeah, you are balding. But hey, take comfort that 28 00:01:40,760 --> 00:01:43,880 Speaker 1: you are not alone. My friends. By age thirty, a 29 00:01:43,959 --> 00:01:47,120 Speaker 1: quarter of all men have already started to lose their hair. 30 00:01:47,680 --> 00:01:50,280 Speaker 1: What's weird is why do humans go bald in the 31 00:01:50,360 --> 00:01:54,600 Speaker 1: first place. Baldness is actually pretty rare in other animals, 32 00:01:54,640 --> 00:01:58,080 Speaker 1: and hair serves a lot of important purposes. It protects 33 00:01:58,080 --> 00:02:00,880 Speaker 1: our heads from the sun, maintain as our body heat 34 00:02:00,920 --> 00:02:05,040 Speaker 1: when we're cold, and may even attract mate. Some researchers 35 00:02:05,080 --> 00:02:08,000 Speaker 1: think it suggests a dominant status or a sign of 36 00:02:08,080 --> 00:02:11,920 Speaker 1: maturity in different societies. In fact, a paper from the 37 00:02:12,000 --> 00:02:17,320 Speaker 1: journal Social Psychological and Personality Science found evidence that women 38 00:02:17,440 --> 00:02:21,680 Speaker 1: find completely bald men more attractive than partially bald ones. 39 00:02:22,200 --> 00:02:25,520 Speaker 1: The study also found that baldness was highly associated with 40 00:02:25,600 --> 00:02:29,840 Speaker 1: two traits, dominance and strength. So if you're starting to 41 00:02:29,919 --> 00:02:33,240 Speaker 1: lose your hair, maybe you should take action, shave it 42 00:02:33,240 --> 00:02:36,239 Speaker 1: all off and show the world what a tough, assertive 43 00:02:36,240 --> 00:02:40,440 Speaker 1: man you are. To understand baldness a little better, let's 44 00:02:40,480 --> 00:02:43,840 Speaker 1: look at the different types that occur. First. The most 45 00:02:43,960 --> 00:02:49,080 Speaker 1: common type is called androgenetic alopecia, otherwise known as male 46 00:02:49,120 --> 00:02:54,320 Speaker 1: pattern baldness. It's related to our inherited genetic predisposition from 47 00:02:54,400 --> 00:02:57,680 Speaker 1: both of our parents. This affects how sensitive we are 48 00:02:57,760 --> 00:03:02,520 Speaker 1: to a hormone called die high drow testosserone hereafter referred 49 00:03:02,560 --> 00:03:07,280 Speaker 1: to as d HT. For most guys, five percent of 50 00:03:07,320 --> 00:03:11,400 Speaker 1: their testosterone is converted into d h T. If you're 51 00:03:11,440 --> 00:03:14,359 Speaker 1: sensitive to d h T, it acts like a toxin 52 00:03:14,440 --> 00:03:19,239 Speaker 1: on your hair follicles, producing thinner, weaker, almost colorless hair 53 00:03:19,440 --> 00:03:24,600 Speaker 1: until hair production in the follicle simply stops. Researchers have 54 00:03:24,720 --> 00:03:28,120 Speaker 1: also found that male pattern baldness also causes men to 55 00:03:28,240 --> 00:03:32,639 Speaker 1: have an abnormal amount of a protein lipid called prostaglandin 56 00:03:32,880 --> 00:03:38,119 Speaker 1: D two. Some dermatologists even think that men could regrow 57 00:03:38,160 --> 00:03:42,320 Speaker 1: their hair if this inhibiting protein were removed. Other types 58 00:03:42,360 --> 00:03:45,480 Speaker 1: of baldness include the female pattern baldness that occurs in 59 00:03:45,600 --> 00:03:51,400 Speaker 1: some women post menopause, an autoimmune disorder called alopecia ariata 60 00:03:51,640 --> 00:03:55,440 Speaker 1: and a condition called telligent effluvium that makes your hair 61 00:03:55,520 --> 00:03:59,280 Speaker 1: fall out faster than normal. People can also have brittle 62 00:03:59,320 --> 00:04:03,720 Speaker 1: hair from air shaft defects, or in rare cases, they 63 00:04:03,760 --> 00:04:07,480 Speaker 1: may even pull out their own hair compulsively if they 64 00:04:07,480 --> 00:04:11,200 Speaker 1: have a disorder called trick atilla mania. You think that 65 00:04:11,280 --> 00:04:14,480 Speaker 1: sounds scary. You can also lose your hair from illnesses, 66 00:04:14,880 --> 00:04:21,440 Speaker 1: fungal infections, burns, chemical applications, medications, and of course, cancer 67 00:04:21,480 --> 00:04:25,760 Speaker 1: treatments like chemotherapy. Smoking is also reported to increase the 68 00:04:25,839 --> 00:04:29,320 Speaker 1: risk of baldness. You should definitely see your doctor if 69 00:04:29,400 --> 00:04:31,960 Speaker 1: your hair starts falling out in clumps or if you 70 00:04:31,960 --> 00:04:40,280 Speaker 1: get a burning, itching irritation on your scouting. Check out 71 00:04:40,320 --> 00:04:42,360 Speaker 1: the brain stuff channel on YouTube, and for more on 72 00:04:42,400 --> 00:04:45,120 Speaker 1: this and thousands of other topics, visit how stuff works 73 00:04:45,200 --> 00:04:59,240 Speaker 1: dot com.