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Hank delves into the details about that very popular substance: caffeine. Like SciShow on Facebook: http://www.facebook.com/scishow Follow SciShow on Twitter: http://www.twitter.com/scishow SOURCES http://coffeefaq.com/site/node/17 http://www.ncpa.org/sub/dpd/index.php?Article_ID=13971 http://www.wisegeek.com/what-are-natural-sources-of-caffeine.htm http://www.wisegeek.com/what-is-kola-nut.htm http://www.independent.co.uk/news/science/under-the-microscope-how-does-caffeine-work-1993056.html http://chemistry.about.com/od/moleculescompounds/a/caffeine.htm http://en.wikipedia.org/wiki/Caffeine http://en.wikipedia.org/wiki/Kola_nut http://www.erowid.org/chemicals/caffeine/caffeine_info1.shtml#2 http://coffeefaq.com/site/node/12
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Text Comments (4127)
Avn Fella (7 days ago)
Yerba mate and Guarana are species from South America not Africa
bhawana sharma (12 days ago)
whats the effect of caffeine on the antibody in humans body
bhawana sharma (12 days ago)
whats the effect of caffeine on the antibodies and how its efect the structure of antibody
Alexander Henry (23 days ago)
Actually, caffeine is addictive - by a very similar mechanism to cocaine. Caffeine indirectly causes the release of dopamine, a neurotransmitter which serves several purposes in the brain, including enhancing focus and as a reward for good behaviors (meaning that, working together with the neurotransmitter glutamate, dopamine helps your mind learn what behaviors are beneficial to you). By raising dopamine levels, drugs essentially mimic behaviors like eating or having sex, but to a far greater degree, hence why they are so pleasurable, and why people become addicted to them. Caffeine causes dopamine release, so it, like cocaine, is addictive. However, so are sugar, food and sex. The thing is, caffeine does not cause as much dopamine to be released - so it isn't anywhere near as addictive. But caffeine is indeed addictive, like cocaine. The mechanism by which opiate addiction occurs is different. While opiates do cause dopamine release, their primary mechanism of action is through decreased norepinephrine release in the locus coeruleus, part of the brainstem. Norepinephrine is a neurotransmitter which leads to alertness and stimulates many of your body's systems, such as your respiratory and circulatory systems. Taking a large amount of an opiate will decrease the norepinephrine in your brainstem, leading you to feel drowsy, relaxed, and can lead to overdose primarily by respiratory depression. When you keep taking the opiate, your brain raises its levels of norepinephrine to counteract the drug. When you stop taking the drug, your levels of norepinephrine are then too high, leading to physical withdrawals - including insomnia, restless leg syndrome, diarrhea, muscle aches, etc. Alcohol and benzopdiazepenes, such as Xanax, have perhaps the most dangerous physical addiction. They increase the GABA in your brain, making you feel relaxed, reducing anxiety, allowing you to overcome your inhibitions. GABA essentially counteracts the over-stimulation of your nervous system. Your brain adjusts to the presence of the drug by over time reducing its normal level of GABA. Then, when an addict stops drinking alcohol or taking a benzo, the levels of GABA are too low in their brain, leading to extreme over-stimulation of their nervous system, which can lead to delerium tremens (shaking, hallucinations, confusion), and even seizures. So caffeine and cocaine are both addictive, although both are primarily psychologically addictive. Due to dopamine-glutamate feedback, you train your mind to associate caffeine/cocaine with survival (your brain thinks you need it to live), so you compulsively seek it and take it. Caffeine is of course far less extreme than cocaine, but it is essentially the same. Heroin, alcohol and benzodiazepenes, and various other drugs, act through different mechanisms. Most do indirectly cause dopamine increase, which can lead to psychological addiction. However, these drugs also act on other neurotransmitters - heroin on opioid receptors and thus norepinephrine, alcohol and benzos on GABA - so they have far more intense physical withdrawals. The question for mainly dopaminergic drugs like caffeine and cocaine is, where do you draw the line between addictive and not addictive? Eating food causes a dopamine spike; so does having sex. Yet most people wouldn't consider these addictive - although, clearly, some people still do them compulsively. Yet everyone considers cocaine addictive, although it really is no different - just causes a lot larger of a dopamine release. Caffeine, I'd assume, is somewhere between eating food and taking cocaine, although I'm not sure where it is (in terms of how much dopamine it causes your brain to release). So the designation of something as addictive is rather arbitrary and non-scientific. But the fact that people are willing to pay 4 or 5 dollars for a Starbucks coffee that they don't NEED (unlike food, which is a biological necessity) every single day, suggests to me that caffeine is indeed addictive. At least, I would personally call caffeine addictive - of course, as I just mentioned, the line between addictive and not addictive is very arbitrary, so I understand that some people might disagree.
Yuki Yoshida (1 month ago)
Although, if you chug down those 5 hour energy drinks several times a day, everyday, I’ve seen people close to me be put in the emergency room because of it... Don’t overdo it guys.
rockerteen8300 (1 month ago)
I would rather go through narcotic withdrawals than caffeine withdrawals, that headache is the worst thing you’ll ever feel, it’s like someone hit you in the head with a sledgehammer.
Shea Alexanderson (1 month ago)
who else watched this specifically because they were consuming caffeine right then?
VILMOSPRO *X* (1 month ago)
No effect after 2 hours... 400ml of mild coffe
Theirly (1 month ago)
My psychiatrist put me on a low caffeine diet. It has been two days and now I feel dead inside.
Omar Jamal (1 month ago)
caffeine does not have a taste
Skin Bear (2 months ago)
weird, I drink two cups of black coffee each work day (4 days a week) and am fine the rest of the day, if I dont drink any caffeine, I just yawn a ton through the entire morning. but on days I dont drink any, and where I can sleep longer, I feel fine, no head aches or "withdrawal" symptoms.
Yiling Cao (2 months ago)
coke is poison, coffee has millions of benefits
dekrome mohamed (2 months ago)
u look l'île u on cocaïne
rightsdeup crocodile (2 months ago)
Sponsored by coke
Terilee Bruyere (3 months ago)
Caffeine helps clear my brain fogginess which are caused by lesions, and helps regulate my randomly low blood pressure (caused by basically the same reason as the fogginess). It may not be the best solution, but it works for now.
Rand Zopyr (3 months ago)
According to my psychologist I have a caffeine addiction - I'm up to 2 or so strong pots per day (I think that puts me close to 2 grams per day of caffeine). So while caffeine is not a mentally addictive substance, it can create a strong physical dependence/addiction. And in people more prone to addiction, it can be addictive.
NeeksArt (3 months ago)
Caffeine makes me tired. Why?
Doom Hunta (3 months ago)
Caffeine=streams of money going right to your bank account
JOSHUA Montoya (3 months ago)
My mother is addicted to coca cola . I wish you could do a video on Coke
Luc Barenghien (3 months ago)
Hello John Green!!
llFike (3 months ago)
What about gastritis?
Kek (3 months ago)
'This machine operates without caffeine' *has a coke at the end*
Seth R.C (3 months ago)
I'm totally willing to admit my dependence- but if it helps me achieve my goals, I'm not worried. Im only taking like max 150-200 mg a day anyway.
Assila 97 (4 months ago)
Without coffee I would never be able to ace my exams. I owe coffee everything
S ? (4 months ago)
Is it weird that caffeine doesn’t effect me? And I’m not really a coffee drinker so I was pretty disappointed when I had coffee for the first time lol
ArceusThe Artist (4 months ago)
Am I the only one who doesn't like coffee so much( I rarely even drink it)
won kim (4 months ago)
Umm... Ok,Hank.
Aaron Wilson (4 months ago)
How much caffeine can one take in a short amount of time without dyeing?
Rhys Logan (4 months ago)
Poppycock! Caffeine is most definitely addictive, withdrawal is not nearly as bad as alcohol, opiates or cocaine perhaps but for me personally it is nearly a week of headaches, muscle pains and lethargy, not to mention extreme depression and lack of motivation that can nearly push me towards suicidal ideation
Rhys Logan (4 months ago)
In my experience it's even worse than nicotine withdrawal
Timothy Cousineau (4 months ago)
I take caffeine pills daily. around 150 mg caffeine each morning, it provides a nice buzz.
Samantha C (4 months ago)
I was diagnosed with caffeine addiction ((yep, it’s a real mental disorder)) and I was drinking over 1000 mg a day of caffeine. I had migraines, insomnia, stomach ulcers and heart problems because of my four energy drinks a day ritual. I tried to go cold turkey and let me tell you, very very bad idea. My already almost non existent appetite decreased even more and I was no longer eating, I was unable to get out of bed or function and got very depressed. It got so bad I passed out in the middle of class due to fatigue and had to go home for two days. I started up caffeine again after that and was back into a normal routine. I then weened off the heavy caffeinating and drink only 400 mg a day. Weening is the way to go, and caffeine addiction is certainly very real and serious, especially for people with depression or decreased levels of dopamine. Your body itself also becomes dependent on it, hence why people who go cold turkey can experience physical exhaustion and very slow response to things.
Juan Milano (4 months ago)
Vamsi Mohana (4 months ago)
I'm drinking Pepsi right now............. CAFFEINE!
Keith Callaway (4 months ago)
Yea drink some water so your body get your electrolytes back half the time I'm on caffine but sense summer is coming hopefully I go back to work so after I'm done usually I drank water more than anything right now caffine is just a plus and also a treat.
Francis George (4 months ago)
Caffeine may not produce a strong desire, like nicotine, but the physical effects aren't slight. The headache is worse than a migraine for big coffee drinkers. I gave up at 4:30pm, and by 11am the next day I was in a lot of pain, and by 2pm it was unbearable and I downed 3 double espressos and 6 ibuprofens, and had to sit in the shower for 40 minutes as they took effect. And the tiredness from caffeine withdrawal is horrendous. My brother had blackouts. All in all, it's functionally addictive. The good news is that it tapers well, unlike alcohol and other GABA or serotonin drugs, so there's no need for all that nonsense to give it up. Just don't go cold-turkey.
Jesse Pinkman (4 months ago)
Caffeine in almost all drinks these days is synthetic and made in china. I wonder why he didn't mention that.
Sponsored by CocaCola.
Bmayo27 (4 months ago)
I love your channel / content. Honestly, I am SHOCKED you’re not a caffeine addict. Congrats on you!
I_M Ali (5 months ago)
A legal drug.
William Smith (5 months ago)
Actually nicotine and caffeine has similar addiction propertys. Caffeine is addictive as well, but not addictive like heroin.
William Smith (5 months ago)
It requires adderal
Connor McGregor (5 months ago)
heavy caffeine use withdrawl can last a month or more
Agustín Auditore (5 months ago)
This video was sponsored by Coke!
Nazar Derkach (5 months ago)
As a child, I thought that caffeine works by ramping up the heart , and pumping more blood (and oxygen) to the brain.
xm377Moyocoyatzin (5 months ago)
Why, hello there young Hank.
108johnny (5 months ago)
It is by will alone that I set my mind in motion. It is by the juice of the bean that thoughts acquire speed, the hands acquire shakes, shakes become a warning. It is by will alone that I set my mind in motion.
Suharto Gutur (5 months ago)
Dude, the moment you said that machine does not require coffee just made my day. I love you for that! The whole grneral coffee craze dives me nuts
star1234922 (6 months ago)
Argument from adverse consequences logical fallacy
Mikayla Stewart (6 months ago)
I love coffee but it doesn't make me alert, in some cases it makes me more tired haha
Nick John (5 months ago)
Mikayla Stewart Interesting. Some people report the same thing. Woah maybe this could be my thesis.
Michael Skinner (6 months ago)
~ O.o
Grant Talkington (6 months ago)
Do a video on the physics of circular breathing!!!
vaiyt (6 months ago)
Guarana is native to south *america* ...
DanTheMan1985ful (6 months ago)
Well for those of you that still drink Caffeine on a regular basis... There is NO other beverage on earth known to man that is more good for you than water. Water is the ONLY beverage that is good for the human body. In fact 2/3 of the human body IS water. Anything that has Sugar, Caffeine, Aspartame, Sucralose, Saccharine, High Fructose Corn Syrup, Sodium, Sodium Citrate, EDTA, Sodium Acetate, or Phosphoric Acid does damage to the body especially your Liver and Kidneys
Strangleyourfriend (6 months ago)
Oh man I've poured in a total of 540 ml caffeine today. Seems like the oncoming night shift will be full of energy then. Only to not have a single drop the next 3 weeks then on it again.
steph steph (6 months ago)
diet coke... "other Coke"... 😉
Mitchell Mammel (6 months ago)
I prefer meth to keep me away
MrFreeman012 (7 months ago)
Adenosine is pretty nice. Caffeine is not so nice. I'm not a stimulant guy. "Threat to society" psh. I scoff at that.
Brooks Butler (7 months ago)
I love this old school scishow
ES50678 (7 months ago)
what about adderall? I've been prescribed it for my adhd and would love to learn more about it from scishow!
Melanie Sutton (7 months ago)
Ever thought of doing a show on sugar withdrawal
Sarah (7 months ago)
"Dedicated Habit" is such an accurate description. "This channel is awesome" is also an accurate description, thank you for what you do!
r3wturb0x (7 months ago)
Video brought to you by big coffee
Mel Stricker (7 months ago)
What was not discussed was why some people are totally unaffected by caffeine. I can drink a pot of very strong coffee and many espresso shots and then go right to sleep. Would have been nice to know since he was talking about how caffeine stimulates the brain (OK, no wisecracks from anyone)
Jack DeLise (7 months ago)
I freebase coffee 7 times a day
StopDropandLOL (7 months ago)
The DSM 5 includes caffeine withdrawal as a syndrome in its latest iteration. After consuming a large amount of it for many years, I quit cold turkey and had negative effects for approximately 2 months after. Incredible anxiety, like anxiety I've never experienced before in my life and that was every waking moment. I couldn't eat, I lost 40lbs in that period (weight I obviously had to lose anyway, but still). I realize this video is out of date now but Caffeine Withdrawal is seriously no joke.
Ps4 all the way (7 months ago)
People have died by drinking to much caffeine
juncedan (7 months ago)
Un anuncio de Coca-Cola para nerds. Brillante, Hank ¿Quién te lo iba a decir?
J3LL1 DR4GON (7 months ago)
Coffee has no effect on me and I rarely ever drink it. Same with soda.
Chriscom28 (7 months ago)
The least time I checked the caffeine in Coca Cola is listed as a flavour. It seems odd to use a stimulant drug as a flavour additive, but that's what I read years ago.
Chriscom28 (7 months ago)
3:47 I actually thought one gram was the LD-50, not 7 grams.
Chriscom28 (7 months ago)
1:19 Yerba matte only contains metabolites. No caffeine. And don't get me started on chocolate.
Chriscom28 (7 months ago)
Probably comes from this silly idea that anything stimulating is because of caffeine. I even found one person who thought tobacco had caffeine in it.😅 I have heart issues so I prefer low caffeine cocaine.😄
Victor Kidd (7 months ago)
Alright, I'm gonna get some coffee now.. bye!
Amber Smith (7 months ago)
caffeine dosnet do anything for me xD
Geoffrey Gore (7 months ago)
So was this episode sponsored by Coca-Cola? That last bit with the perfectly turned can seems awfully well-planned....
lamsorz (7 months ago)
sponsored by Coca Cola TM
MrMeow Catty (7 months ago)
What if Caffeine completely fails from the very start to give you that wakey wakey stimulation at all what so ever, from the very first cup of the day, even if you don't drink it much at all?
Kyech K (7 months ago)
Lol that Ad!!
if caffein is legal why isn't cocaine? the government is trying to control us
ViraIshnia (7 months ago)
Anyone else get a headache from that background?
Nick John (5 months ago)
ViraIshnia Do you have epilepsy? Better check with Eeg scan. Better safe than sorry.
Matija Kruhoberec (7 months ago)
2018? Anyone?
mynamewhatis (7 months ago)
Cocaine actually isn't technically addictive either
Rick Eisner (8 months ago)
For the Psychological well being of my coworkers. Caffeine and NIcotine are necessary.
guitarherochampion92 (8 months ago)
Love the Taco John's cup in the lower left side of the table 😂 They got some great burritos for a fast food chain place
A Tr (8 months ago)
When I drink caffeinated beverages, I drink it for the sugar.
Pixx (8 months ago)
I'm incredibly resistant to caffeine and I hate it so much... 😫 I swear, I can drink a pot of coffee and go right back to sleep 😢
drew rosander (8 months ago)
how fun would it be to split a pint of super pricey vodka and a quarter of benzoyl ecgonine (bLoW) with uncy Hank? #squadgoals
drew rosander (8 months ago)
Amish Cowboy (8 months ago)
This was made on my 8th birthday
You guys should do a video on mitragyna speciosa commonly referred to as kratom. Kratom is in the coffee family and in some ways it's almost the opposite to coffee as it's alkaloids mainly the mitragynine alkaloids which affect the opioid receptors causing a relaxing and pain relieving effect. Kratom is increasingly becoming more popular in the United States as an alternative from dangerous pharmaceutical opiates sparking controversy as it is a great method for getting off opiates since it has many similar effects to opiates albeit much more mild, but without the debilitating health issues caused by pharmaceutical opiates such as liver damage, the high risk for addiction, and possible overdoses. Kratom is just about as addicting as coffee while also having no risk for overdose. Many pharmaceutical companies are trying to lobby against it being legal as they want to continue to capitalize off of their drugs while also producing negative media towards the plant even though several studies from universities such as the University of Florida have proven that this plant is safe and beneficial. Unfortunately our government is controlled by big corporations with lots of money. This will undoubtedly be a major blow to personal liberties, and many who use it as an alternative to stay away from opiates like Oxycontin (I being one myself). Since kratom has come into my life I'm proud to say I've been clean of prescription opiates. I've lost two cousins from Hydrocodone overdose and I know several others who have died from opiates especially heroine. Kratom could be the solution to our heroine epidemic, but unfortunately pharma companies want to keep people hooked on their drugs. You guys can be a voice for change and I do implore to do so. Myself and many others would be incredibly grateful and I really think it would make for an interesting video.
ExclusiveCrazyExpert (8 months ago)
sleepless ....
light564 (9 months ago)
I can happily say when God-made me he broke the mold because every time when I had caffeine which is a long time ago it always put me to sleep. While hot chocolate wakes me up. And I'm talking about the caffeine free one so I stick to non caffeinated drinks at all times
Carl Roy (9 months ago)
When you exceed 100 cups of coffee do you turn into the Flash?
Nick John (5 months ago)
Carl Roy LOL. Futurama reference?
PitchBlack (9 months ago)
ASAP science copied you
rachel (9 months ago)
I think the "friend" he was talking about was John lol
Lucas Lee (9 months ago)
how is caffiene good
Idea 86 (9 months ago)
I want a coke now
Thunder Blyat (9 months ago)
Que the shameless advertising
Dylan Almeida (9 months ago)
Guarana and yerba matte is not from south africa! It's from south America.....
Vyto Vy (9 months ago)
caffeine science explained Covering: dosages, effectiveness and much more! :) https://www.youtube.com/watch?v=LVozzXnzkiE&feature=youtu.be
ItzJeff (9 months ago)
Once I drank a Mountain Dew late and I was up till 3 a clock

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